Neonatologia - Neonatal Handbook 2006

Last Updated 08-Feb-2006. Authorised by: Neonatal Handbook Editorial Board. Enquiries: Ellen Bowman & Simon Fraser.

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Disclaimer The neonatal guidelines presented on this site were developed by clinicians primarily for use by medical and nursing personnel working in newborn special care units throughout Victoria. They detail the initial assessment and management of many common (and some rare but important) conditions encountered during the early newborn period. They do not constitute a textbook, rather, they are designed to acquaint the reader rapidly with the clinical problem and provide practical advice regarding assessment and management. These guidelines have been developed, where possible, by achieving consensus between practicing clinicians. They do not however necessarily represent the views of all neonatologists working in Melbourne’s Neonatal Intensive Care Units. The recommendations contained in these guidelines do not indicate an exclusive course of action, or serve as a standard of medical care. Variations, taking individual circumstances into account, may be appropriate. The authors of these guidelines have attempted to ensure the information upon which they are based is accurate and up to date. Users of these guidelines should confirm that the information contained within them, especially drug doses, is correct by way of independent sources. No responsibility is accepted for any inaccuracies or information perceived as misleading.

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Neonatal Handbook Index 1. Abdominal Wall Defects........................................................................................................................... 05 2. Ambiguous Genitalia ................................................................................................................................06 3. Apnoea .......................................................................................................................................................09 4. Bleeding Disorders In The Neonate ........................................................................................................12 5. Blood Gas Interpretation ..........................................................................................................................14 6. Blood Pressure .........................................................................................................................................16 7. Bowel Obstruction ....................................................................................................................................19 8. Breastfeeding Issues ................................................................................................................................21 9. Bronchopulmonary Dysplasia .................................................................................................................26 10. Chickenpox (Varicella Zoster) ...............................................................................................................30 11. Cleft Lip And Palate ................................................................................................................................31 12. Common Limb Problems .......................................................................................................................33 13. Congenital Adrenal Hyperplasia ............................................................................................................35 14. Congenital Diaphragmatic Hernia .........................................................................................................36 15. Congenital Infection …………………………………………………………………………………………….39 A. Toxoplasmosis …………………………………………………………………………………………..39 B. Rubella …………………………………………………………………………………………………… 41 C. Cytomegalovirus (CMV) Infection ……………………………………………………………………42 D. Herpes Simplex Virus (HSV) …………………………………………………..……………………...44 E. Syphilis ……………………………………………………………………………………………………45 16. Cyanosed Infant Assessment …………………………………………………...…………………………….47 17. Developmental Care ………………………………………………...…………………………………………..51 18. Developmental Dysplasia Of The Hip …………………………………………………………………….….53 19. Dysmorphology Assessment Of The Newborn ………………………………………….…………………54 20. Immediate Management Of The Tiny Baby (1,000g>) ……………………………………….…………….58 21. Fetal Hydronephrosis …………………………………………………………………………………………...60 22. Gastro-Oesophageal Reflux ……………………………………..…………………………………………….63 23. Prevention Of Gbs Sepsis ………………………………………………..…………………………………….64 24. Glucose-6-Phosphate Dehydrogenase Deficiency ……………………………………..…………………66 25. Headbox Oxygen Set-Up ..……………………………………………………………………………………...67 26. Hypoglycaemia…………………………………………………………………………………………………...69 27. Hypospadias ……………………………………………………………………………………………………...72 28. Hypothyroidism ………………………………………………………………………………………………….73 29. Immunisation Of Preterm Infants ..…………………………………………………………………………...75 30. Incubator To Cot Transfer ……………………….……………………………………………………………..80 31. Infant Of The Chemically Dependent Woman ……………………………………………………………...81 32. Infant Of The Diabetic Mother (IDM) …………………………………..……………………………………...84 33. Inguinal Hernia And Hydrocele ……………………………………………..………………………………...86 34. Intramuscular (Im) Injection ……………………………………………………………………………………87 35. Intraosseous Needle Insertion ………………………………………………………………………………...89

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36. Intravenous Electrolyte Correction …………………………………………………………………..………91 37. Intravenous Infusion For Scn Admissions …………………………………………………….…………...92 38. Intubation ………………………………………………………………………………………………………….94 39. Jaundice In The First Two Weeks Of Life …………………………………………………..……………….97 40. Listeria Monocytogenes Infection …………………………………………………………………………..101 41. Meconium Aspiration Syndrome …………………………………………………………...……………….102 42. Meconium Stained Liquour, Delivery Room Management ……………………………………………..104 43. Meningomyelocele ……………………………………………………………………………………………..105 44. Metabolic Disease A Neonatal Approach …………………………….……………………………………106 45. Necrotising Enterocolitis ……………………………………………...……………………………………...109 46. Normal Laboratory Values ……………………………………………………..……………………………..112 47. Osteopenia Of Prematurity ………………………………………………...…………………………………116 48. Parvovirus Infection …………………………………………………………………………………………...117 49. Percutaneous Central Venous Catheter Insertion ….........................................................................118 50. Persistent Pulmonary Hypertension Of The Newborn …………………………………………….…….121 51. Pneumothorax Drainage ………………………………………………………………………………………123 52. Polycythaemia …………………………………………………………………………………………………..125 53. Respiratory Distress Syndrome (RDS) ……………………………………………………….…………….126 54. Resuscitation ……………………………………………………………………………………………………128 55. Retinopathy Of Prematurity …………………………………………………………………………………..131 56. Small For Gestational Age Infants ……………………………………………..……………………………134 57. Shock ……………………………………………………………………………………………………………..136 58. Seizures ………………………………………………………………………………………………………….140 59. Sepsis …………………………………………………………………………………………………………….143 60. Single Umbilical Artery ……………………………………………………..………………………………...148 61. Small For Gestational Age Infants …………………………………………………………..………………149 62. Supraventricular Tachycardia ……………………………………………………………………...………..151 63. Surfactant Replacement Therapy …………………………………………………………………………...154 64. Thrombocytopenia ……………………………………………………………………………………………..155 65. Thrombosis In Newborns ……………………………………………………………………………………..157 66. Tracheo-Oesophageal Fistula/Oesophageal Atresia ……………………………………………….……159 67. Transfer Guidelines ……………………………………………………...…………………………………….161 68. Transfusion ……………………………………………………………………………………………………...164 69. Tuberculosis (TB) …………………………………………………..………………………………………….166 70. Umbilical Artery Catheterization ……………………………………………………………..……………..167 71. Umbilical Cord Care ………………………………………………………………..………………………….169 72. Umbilical Hernias ………………………………………………………………………………...…………….170 73. Umbilical Vein Catheterisation …………………………………………………………………………...….171 74. Undescended Testes (Cryptorchidism) ……………………………………………………………..……..173 75. Vomiting In The Newborn Infant ………………………………………………..…………………………...174

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1. ABDOMINAL WALL DEFECTS A. B. C. D. E. F.

Summary Introduction Gastroschisis Exomphalos Investigation Management

A. Summary: - the abnormality should be covered with cling wrap - pay careful attention to thermoregulation and fluid management - refer early via NETS to tertiary referral centre with surgical facilities B. Introduction: - The diagnosis of exomphalos and gastroschisis is often but not invariably made antenatally by ultrasound. - These babies will usually be delivered at a tertiary referral centre. C. Gastroschisis: - small defect of the anterior abdominal wall to the right of the umbilicus through which bowel herniates - occurs in between 1:10,000-30,000 births - no covering sac, the surface of the bowel is usually oedematous and matted - associated anomalies are reported in up to 15% (mainly gastrointestinal) - prematurity and growth restriction are frequent - necrotising enterocolitis and malabsorption may occur - survival rates are about 90% D. Exomphalos: - a protrusion of intestinal contents through the abdominal wall at the umbilicus - covered by a thin membrane of amnion and peritoneum - herniation of the liver accompanies intestine if a large sac, omentum and intestine are present if a small -

sac associated anomalies occur in 45 – 67% (eg trisomies, cardiac defects, G.I. and renal anomalies) survival rates are mainly dependent on whether other anomalies are present necrotising enterocolitis and malabsorption are associated complications

E. Investigation: - look for associated problems: • • • •

remember exomphalos can be associated with Beckwith-Wiedemann Syndrome (includes macroglossia, pathognomonic horizontal ear crease and hypoglycaemia) cardiac malformations renal abnormalities karyotype infants with exomphalos

F. Management: - wrap abdomen of baby in cling film with gut lying well supported either on the abdomen if a small lesion or

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supported by a foam rubber "doughnut". If in one position a length of bowel appears to have impaired blood supply or drainage i.e. looks purple or black, try gentle manipulation of the bowel into other positions to see if the circulation can be improved – the bowel may need to be rotated on its pedicle to achieve a better circulation cotton wool covering or the use of moist packs is contraindicated. (Cotton wool adheres to the bowel wall, cannot be fully removed and causes peritoneal granulomas; moist packs rapidly become cold and lead to hypothermia) pass size 8 NG tube, place on continuous low-pressure suction or leave on free drainage and aspirate every 60 minutes place nil by mouth start IV infusion - Give usual Day 1 fluids infants with gastroschisis may loose large amounts of colloid fluid into the inflamed gut requiring vigorous colloid fluid replacement (eg Albumin 5% 10-20 mL/kg). Watch blood pressure

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check blood glucose immediately and monitor closely because of the association of Beckwith-Wiedemann syndrome with exomphalos monitor temperature frequently. Patients with a ruptured exomphalos sac or gastroschisis may have major problems with temperature control due to evaporative heat loss contact paediatric surgeon and NETS to arrange transfer to surgical centre give antibiotics: Penicillin, Gentamicin (preferably after blood culture) take blood for FBE, electrolytes, blood culture, group and hold for cross match of blood

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2. AMBIGUOUS GENITALIA A. B. C. D. E. F. G. H.

Summary Introduction Management Clinical Evaluation Investigation

Differential diagnoses Ongoing Management Further Reading

A. Summary: Be very careful in your choice of words during the diagnostic period and do not sign the birth certificate until a definite decision as to the sex of rearing has been reached. - be aware of associated metabolic problems - palpable gonads imply the presence of testicular tissue - decisions as to sex of rearing may have no relationship to karyotypic, gonadal or genital status in isolation - there is some ongoing controversy as to when is the appropriate time to make decisions as to sex of rearing and who should be party to those decisions

B. Introduction: Approximately 1 in 4,500 births are complicated by ambiguous genitalia. This situation is rarely anticipated and can be a source of great distress for parents, delivery room and nursery staff. Often there can be pressure on medical staff to "make it better" and assign a gender to the child arbitrarily in the first few hours after birth. This must be avoided at all costs. Staff must be careful in their choice of words when discussing the baby with parents. It is unnatural not to discuss a baby without using the terms "he" or "she" and it is easy to accidentally refer to the baby in a gender-orientated way. Parents who are often greatly distressed may assume that medical and nursing staff "know" what the gender of the baby "really is". Consequently any terminology used (deliberately or accidentally) will be given great emphasis by parents. This may lead to confusion and distress later if the suggested sex of rearing is at odds with initial "off the cuff" remarks. Parents may seek advice regarding the naming of their infant. The usual advice is to select non-ambiguous names (ie using gender specific names) since it is thought that by encouraging the use of ambiguous (non-gender specific) names, one is implying an ongoing sense of "ambiguity".

C. Management: - Be very careful in your use of terms when discussing the baby with ambiguous genitalia. Appropriate, non-gender orientated terms are listed in Table 1. Never refer to the baby in question as "it" Table 1: Suggested phenomenology when dealing with babies with ambiguous genitalia.

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FEMALE

AMBIGUOUS

MALE

She Clitoris Labia Ovaries Vagina, urethra

Your baby Phallus Folds Gonads Urogenital sinus

He Penis Scrotum Testes Urethra

The situation should be treated as a medical emergency, with paediatric endocrine advice being sought immediately

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D. Clinical Evaluation: Genital ambiguity can be quantified according to the Prader scale (Figure 1). Other relevant clinical details include: - gonads palpable in the labioscrotal or inguinal regions - size of the phallus - pigmentation of the genitalia - syndromic features - metabolic condition of the baby (paying particular attention to glucose, sodium and potassium) The baby's mother should also be examined for signs of hyperandrogenism. Care should be taken in the interpretation of examination findings in growth retarded or premature female neonates. These children may exhibit atrophic labia and clitoral oedema giving them an appearance of "pseudoambiguity". It is a moot point where the boundary lies between severe perineal hypospadias and genital ambiguity. Inability to palpate the gonads in this situation may be indicative of a diagnosis other than isolated hypospadias. Figure 1: Prader staging system for the degree of virilisation of the external genitalia.

Prader 0: Normal female external genitalia.

Prader 1: Female external genitalia with clitoromegaly.

Prader 2: Clitoromegaly with partial labial fusion forming a funnel-shaped urogenital sinus.

Prader 3: Increased phallic enlargement. Complete labioscrotal fusion forming a urogenital sinus with a single opening.

Prader 4: Complete scrotal fusion with urogenital opening at the base or on the shaft of the phallus.

Prader 5: Normal male external genitalia.

(Prader Von, A. (1954). "Der genitalbefund beim Pseudohermaproditismus femininus des kongenitalen adrenogenitalen Syndroms. Morphologie, Hausfigkeit, Entwicklung und Vererbung der verschiedenen Genitalformen." Helv. Pediatr. Acta. 9: 231-248.)

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E. Investigation: Blood should be sent for: - electrolytes - gonadotropins (LH, FSH) - testosterone - urgent karyotype - serum 17-hydroxyprogesterone (17OHP) levels (after day 3 of life) Pelvic ultrasound (carried out by an experienced sonographer) should be undertaken as soon as possible. Other investigations which may or may not be subsequently relevant include: - sinugram - human chorionic gonadotropin stimulation test (to assess testosterone and dihydrotestosterone synthesis capability)

F. Differential diagnoses: a) Gonads palpable, 46XY:

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gonadal dysgenesis partial androgen insensitivity biosynthetic defect in either testosterone or dihydrotestosterone production b) Gonads impalpable, 46XX: - Congenital adrenal hyperplasia - gonadal dysgenesis - exogenous androgen exposure c) Mosaic karyotype: - gonadal dysgenesis

G. Ongoing Management: Decision as to sex of rearing is made after opinions have been sought from the endocrine and surgical teams. It should be undertaken with the baby's parents after all the relevant investigation results have been discussed. The decision that will be influenced by an amalgam of:

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the baby's karyotype gonadal status internal and external genital duct status potential for fertility and adequate sexual function cultural influences

Do not complete the baby's birth certificate until the sex of rearing has been decided. There is a 60 day period of grace between the birth of a child and when their birth certificate needs to be completed - hence there is no rush. If the "wrong" sex is entered on the form it is extremely difficult to correct and requires judicial intervention. Long term care:

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families require long term medical and psychological support corrective surgery is usually undertaken within the first year of life infants with CAH and congenital syndromes have additional requirements for ongoing medical therapy disclosure to the patient as to their diagnosis is usually undertaken in mid to late adolescence when they have the ability to understand complex issues such as chromosomes, hormones etc, and possess some degree of emotional maturity

H. Further Reading: • •

Reiner WG Assignment of sex in neonates with ambiguous genitalia. Curr Opin Pediatr 1999 Aug;11(4):363-5. Ahmed SF, Hughes IA The genetics of male undermasculinization.Clin Endocrinol (Oxf) 2002 Jan;56(1):118

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3. APNOEA A. B. C. D. E. F. G.

Summary Introduction Differential Diagnosis Investigations Management Areas of Uncertainty in Clinical Practice References

A. Summary: -

initially monitor all infants <34 weeks for breathing and heart rate apnoea on day 1 may not be due to idiopathic apnea of prematurity -consider sepsis or impending respiratory failure (esp when there is underlying surfactant deficiency) sudden increases in severity/frequency of apnoiec episodes suggests new pathology treatment requires acute resuscitation followed by diagnosis and treatment of specific causes symptomatic control with medication or ventilatory support may be required

B. Introduction: Apnoea is defined as no inspiratory gas flow for 20 seconds or shorter if associated with bradycardia (<100bpm), cyanosis or pallor. Apnoea may be classified as

a) Central apnoea - a pause of alveolar ventilation due to immaturity of neurological controls. This may be provoked by: - gavage feeding - aggressive pharyngeal suction - gastro-oesophageal reflux b) Obstructive apnoea - a pause in alveolar ventilation due to obstruction of the upper airway (usually at the level of the pharynx) - not detected by motion sensing monitors c) Mixed apnoea - a combination of central and obstructive apnoea - seen in over 50% of infants Apnoea is distinguished from periodic breathing (respiratory pauses > 3 seconds duration with less than 20 seconds of respiration between pauses) which may occur normally. Apnoea occurs in: - most infants <30wks - about 50% of infants at 30-32wks - about 10% of infants at 34wks Apnoea usually resolves by the time the infant is 36wks postconceptual age. There is evidence that apnoea of prematurity is not a risk factor for SIDS. There is no evidence that apnoea of prematurity causes subsequent neurodevelopmental morbidity although recurrent apnoea causes concern because of effects of repeated episodes of tissue hypoxia (especially on the gut and brain).

C. Differential Diagnosis: Apnoea occurs with increasing frequency the more immature the infant. Various conditions may cause or aggravate apnoea:

a) Anatomical anomalies of the upper airway: - choanal atresia, micrognathia, macroglossia, b) c) d) e) f) g) h) i) j)

tracheomalacia Infection: - sepsis, necrotizing enterocolitis Temperature disturbance: - hypothermia, hyperthermia Metabolic: - hypercalcemia, hypoglycemia, hyponatremia, acidosis Haematological: - anaemia, polycythemia Pulmonary: - impending respiratory failure CVS: - causes of cardiac failure or impaired oxygenation eg PDA CNS: - intraventricular haemorrhage, intracranial haemorrhage, seizures, asphyxia, increased intracranial pressure GIT: - Gastro-oesophageal reflux Drugs: - prenatal - narcotics, betablockers postnatal - sedatives, hypnotics, narcotics

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Apnoea on day 1 is not normal. A sudden increase in severity/frequency of episodes suggests new pathology. The following lists important potential causes of apnoea according to infant age: a) Day 1-2: - sepsis - hypoglycemia - impending respiratory failure - polycythemia b) Days 3-6: - sepsis - impending respiratory failure - PDA - massive IVH - apnoea of prematurity c) Late: - sepsis - progressive post-extubation atelectasis - out grown dose of theophylline/caffeine - gastro-oesophageal reflux - presenting symptom of RSV infection

D. Investigations: A thorough physical examination is mandatory with emphasis on cardiorespiratory and neurological status. Usually a septic screen and blood glucose estimation will be required. Further tests are determined by the need to look for specific conditions (see differential diagnosis) causing or aggravating apnoea.

E. Management: 1. The acute apnoeic episode: - Stimulate e.g. tickle or flick the feet or stroke the abdomen - Aspirate airway if no response, briefly suction the oropharynx then repeat stimulation - Bag and mask ventilation if still no response, using the amount of oxygen the infant was receiving prior to the apnoea (not 100%). Only increase the concentration of oxygen (by steps of 5-10%) if the infant's condition fails to improve despite effective bag and mask ventilation - If still no response, Positive Pressure Ventilation is required 2. Management of specific causes: Treatments will depend on the specific cause of the apnoea. 3. Symptomatic management: Various methods can be used to provide symptomatic control of apnoea until the infant 'out grows' this problem. When is symptomatic treatment useful? There is no 'right' answer to this question. The following suggestions fall within the spectrum accepted at most neonatal units. Episodes needing brief stimulation for cyanosis + bradycardia: >6 every 12hrs Episodes needing vigorous stimulation +/- oxygen: >1 every 24hrs Episodes needing PPV +/- oxygen: >1 episode every 24hrs

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Attention should be given to posturing the infant to avoid obstruction of the upper airway Feeds may be given more frequently as smaller boluses to avoid excessive distension of the stomach Some infants benefit from maintaining their thermal environment in the lower part of the neutral thermal range Low flow oxygen into the incubator (approx 23-24%) may help when levels of oxygenation between apnoeas are borderline satisfactory. If used continuous saturation monitoring is needed to avoid risks of hyperoxia Medications

Both caffeine and theophylline are effective in short term reduction of symptoms - caffeine may have advantages because of its higher therapeutic ratio, once daily dosing, lack of need to assay blood levels. Longer term outcomes have not been thoroughly examined. Prophylactic use of caffeine has not been shown to be effective. Currently, caffeine is only available upon application to Canberra under the Special Access System.

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Dosages

Aminophylline/ Theophylline

Loading dose 6mg/kg stat Maintenace dose

2.5 to 4mg/kg/dose 12 hourly(2.5mg wk1, 3mg wk2, 4mg>wk2) Commence maintenance 24hrs after loading dose for infants ¡<=1kg, 12hrs after loading dose for infants>1kg

Medication is usually stopped when the infant is >=34wks gestation and apnoea free for 1 to 2 weeks. Monitoring is continued for a further week after medication is stopped.

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Positive distending pressure - treats both obstructive and mixed apnoea

Proposed mechanisms of action: - prevents pharyngeal collapse by splinting the nasopharynx, stabilizes the chest wall musculature, alters various reflexes (Herring-Breuer, Intercostal inspiratory inhibitory). Nasal CPAP may be given by various techniques - most simply via a cut down endotracheal tube inserted 2cm into one nostril. Initial pressure settings for nasal CPAP are 5 -7 cm H2O which may be adjusted according to clinical response. Possible side effects - barotrauma, nasal irritation, abdominal distension and feed intolerance.

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Positive pressure ventilation

When uncontrolled by other means intubation and positive pressure ventilation will be required. Initial ventilator settings will use short inspiratory times and minimal PIP pressures to minimise risk of lung injury.

F. Areas of Uncertainty in Clinical Practice: a) Minimising apnoea after extubation from PPV: Both CPAP and theophylline will reduce post-extubation apnoea.

b) The place of blood transfusion in treatment of apnoea: Presence and severity of apnoea correlate poorly with the presence of anaemia. Theophylline has been shown superior to blood transfusion in improving symptoms of apnoea in anaemic infants (but in a very small study). The clinical benefits from transfusion appear greater the more severe the level of anaemia (the effects are trivial when the haemoglobin is about 100g/L). c) Kinesthetic stimulation (e.g. oscillating mattresses) to treat apnoea: Not recommended for either prophylactic or symptomatic control of apnoea. d) Doxapram as medication for symptomatic control of apnoea: May reduce apnoea in the first 48 hours of treatment, longer term risk and outcomes have not been established, It has similar short term effect to the methylxanthines in obtaining symptomatic control but must be given as a continuous IV infusion limiting any usefulness. The long term safety of doxapram has not been well studied. e) Caffeine and Prematurity (CAP) Trial: Currently in Melbourne infants are being enrolled in a trial testing the use of caffeine against placebo in the management of apnoea. The main outcome is long-term survival free of major disability. f) Use of oxygen by nasal cannulae to control apnoea: High oxygen flows given by nasal cannulae may achieve significant positive distending pressures. Possible side effects include inadequate heating and humidification leading to temperature control problems and increased nasal irritation. Pressures generated are not able to be monitored with this system.

G. References: •

• • •

Infantile Apnea and Home Monitoring, National Institutes of Health Consensus Development Conference Statement 1986 http://consensus.nih.gov/cons/058/058_intro.htm Effect of blood transfusion on apnoea, bradycardia and hypoxemia in preterm infants C.F.Poets, U.Pauls, B.Bohnhorst Eur J Pediatr (1997)156: 311-316 Transfusion-induced changes in the breathing pattern of healthy preterm anemic infants P.Sasidharan, R.Heimler Ped. Pulmonlogy (1992)12(3):170-3 Relationship between determinants of oxygen delivery and respiratory abnromalities in preterm infants with anemia E.M.Bifano, F.Smith, J.Borer J.Pediatr 120(2Pt1):292-6, 1992 Feb High-Flow Nasal Cannulae in the Management of Apnea of Prematurity: A comparison with conventional nasal continuous positive airway pressure C.Sreenan, R.P.Lemke, A. Hudson-Mason, H.Osiovich Pediatrics 2001 107(5) 1081-3

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4. BLEEDING DISORDERS IN THE NEONATE A. B. C. D. E. F. G.

Summary Introduction Clinical presentation Differential diagnosis Laboratory investigations Interpretation of Lab investigations in a bleeding neonate Management

A. Summary: - history, physical examination and determining whether the neonate is "well" or "sick" is helpful in -

assessment of a bleeding neonate simple and widely available lab tests are useful in investigating a bleeding neonate treatment depends on the cause of bleeding and clinical condition of the neonate "treat the baby not the numbers" consult a Paediatric Haematologist if in doubt

B. Introduction: Neonates are susceptible to bleeding for various reasons: - immaturity of the haemostatic system because of quantitative and qualitative deficiency of coagulation factors - maternal disease and drugs - birth trauma - other conditions eg sepsis and asphyxia

C. Clinical presentation: Bleeding in neonates may present with: - oozing from the umbilicus or stump - cephalhaematoma - bruising more than that anticipated after delivery - bleeding from peripheral venipuncture or procedure sites - bleeding into scalp - bleeding following circumcision - petechiae - intracranial haemorrhage - bleeding from mucous membranes - unexplained anaemia and hypotension A detailed history and complete examination is essential in the assessment of a bleeding neonate. Particular points in the history include: - maternal diseases such as ITP, preeclampsia and diabetes - maternal exposure to drugs such as aspirin, anticonvulsants, rifampicin and isoniazid - family history of bleeding disorders - previous affected siblings Physical examination will determine whether the neonate is "well" or "sick", which is very useful as the differential diagnosis is very different in the two circumstances.

D. Differential diagnosis: Causes of bleeding in a "well" neonate: - immune thrombocytopenia (alloimmune or autoimmune (maternal ITP)) - vitamin K deficiency - inherited coagulation factor deficiencies such as haemophilia - bleeding from anatomic lesions such as a haemangioma, A-V malformation Causes of bleeding in a "sick" neonate: - DIC - usually associated with sepsis, asphyxia, severe RDS or NEC - consumption thrombocytopenia without depletion of coagulation factors - liver failure

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Bleeding at a single site is more likely to have an anatomic or structural component. Major bleeding from any primary cause may induce a secondary DIC, which may mask the original pathology.

E. Laboratory investigations: -

first line tests include: • platelet count • APTT • PT • fibrinogen • d-dimer

The results should be interpreted in the context of normal laboratory values for gestation and postnatal age.

Interpretation of Lab investigations in a bleeding neonate: a) Isolated prolonged APTT, consider:

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factors XII, IX, XI and VIII deficiencies heparin early DIC b) Isolated prolonged PT, consider: - early DIC - liver disease - vitamin K deficiency - factor VII deficiency c) Combined prolonged APTT and PT+/- low fibrinogen, consider: - DIC - liver disease - vitamin K deficiency - rarely inherited factor deficiency e.g. prothrombin deficiency d) Normal APTT, PT, platelet count, fibrinogen, consider: - factor XIII deficiency - platelet function defect - A-V malformation - severe neutropenia (bleeding from umbilical stump) Von Willebrand Disease rarely presents in the newborn period. Factor XII deficiency causes a prolonged APTT, but no clinical bleeding.

F. Management: Management depends on: - the cause of bleeding and - clinical condition of the neonate 1. DIC:

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treat the primary condition blood products i.e. platelets and FFP are used on clinical grounds: • 10-15 ml/ kg of FFP can be given to correct coagulation abnormality • if platelets <50 and actively bleeding, transfuse platelets 2. Vitamin K deficiency: - IV vitamin K1, 1mg is usually effective within hours - also give FFP 10-15 mls/kg to immediately increase the levels of clotting factors 3. Thrombocytopenia: - Refer to Thrombocytopenia 4. Inherited factor deficiency: - initial therapy with FFP after blood taken for specific factor assays - specific factor replacement when diagnosis known

G. Further Reading: •

Christensen, MD : Hematologic problems of the neonate. W.B. Saunders Company , first edition; 2000.

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5. BLOOD GAS INTERPRETATION A. B. C. D. E. F. G. H. I. J. K. L.

Introduction pH Acid (H+) Respiratory Acidosis Respiratory Alkalosis Metabolic Acidosis Metabolic Alkalosis The Base Excess Acid-Base Disorders The Blood Gas Machine Areas of Uncertainty in Clinical Practice References

A. Introduction: Blood gases are helpful in determining the adequacy of respiratory function of the baby (oxygenation and ventilation) as well as the baby's acid/base balance. Blood gases can be performed from arterial (either a stab or via an arterial line), venous (through an intravenous cannula) or capillary (heel prick) specimens. Repeated arterial stabs are strongly discouraged, as they are painful and do not represent oxygenation as well as pulse oximetry. Arterial stabs may be taken from the radial artery (provided there is also a palpable ulnar pulse) or from the brachial artery, although this is in close proximity to the median nerve. All three specimens will give a good assessment of acid/base status and pCO2, whereas arterial specimens are required to assess pO2. It is always important to note the FiO2 (percentage inspired oxygen) when interpreting blood gases. Each unit should have their own reference ranges.

B. pH: The pH is a negative logarithm of hydrogen ion concentration [H+], that is a decrease in pH from 7.0 to 6.0 represents a ten-fold increase in [H+]. Although each unit will define neonatal pH a little differently, if, say a normal neonatal pH is defined as 7.30 to 7.40, then:

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pH > 7.4 is an alkalosis pH < 7.3 is an acidosis

The pH is proportional to HCO3 (or base excess), therefore:

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an abnormal increase in HCO3 (or base excess) increases the pH (metabolic alkalosis) an abnormal fall in HCO3 (or base excess) decreases the pH (metabolic acidosis)

The pH is inversely proportional to pCO2, therefore:

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an abnormal increase in pCO2 decreases the pH (respiratory acidosis) an abnormal decrease in pCO2 increases the pH (respiratory alkalosis)

C. Acid (H+): Many organic acids are produced during normal metabolism. Sometimes they can accumulate in the blood (e.g. lactic acid). The hydrogen ion (H+) may be 'mopped up' by buffers including bicarbonate (HCO3). Bicarbonate is unique because it can be converted to CO2, which can be blown off by the lungs (provided the baby is not in respiratory failure). The following bi-directional equation demonstrates this:

D. Respiratory Acidosis: (e.g. pCO2 >= 50 mmHg, pH < 7.30) This occurs when the pCO2 is abnormally high and is due to inadequate alveolar ventilation. Causes include depression of the breathing centre in the brain, upper airway obstruction, stiffness of the chest wall or significant ventilation/perfusion imbalance. If the respiratory acidosis is chronic, the body will respond by trying to excrete acid and retain bicarbonate in the urine resulting in a compensatory rise in serum bicarbonate (metabolic alkalosis). The treatment of a respiratory acidosis is to treat the underlying cause and to consider the need for or increase mechanical ventilation. The latter is achieved by either increasing the tidal volume (increasing PIP or decreasing PEEP) or by increasing the respiratory rate.

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E. Respiratory Alkalosis: (e.g. pCO2 < 35 mmHg, pH > 7.40) This occurs when the pCO2 is abnormally low and is usually due to excessive mechanical ventilation or to abnormal control of ventilation (e.g. during hypoxic-ischaemic encephalopathy). The baby may also be trying to compensate for a primary (intracellular or extracellular) metabolic acidosis, although the pH will never become alkalotic (as the baby will never over-compensate). The treatment of a respiratory alkalosis is to wean the mechanical ventilation by reducing PIP or tidal volume, then respiratory rate.

F. Metabolic Acidosis: (e.g. HCO3 < 17 mmol/L or B.E. < minus 6.0 mEq/L, pH < 7.30) This may occur where there is a rise in free H+ ions that cannot be totally buffered. In this case the anion gap is increased. Causes include lactic acidosis secondary to tissue hypoxia (e.g. hypotension, sepsis and PDA) or the inability to excrete/buffer accumulated organic acids (e.g. protein loading and renal immaturity). Another common cause of metabolic acidosis, particularly in the extremely premature infant is excessive loss of HCO3 in the urine or gut. In this case the anion gap is normal. Metabolic acidosis is rarely due to an inborn error of metabolism. The treatment of a metabolic acidosis is to treat the underlying cause, consider volume expansion (e.g. 10 mls/kg of normal saline) if the baby is thought to be hypovolaemic or to administer NaHCO3 if the metabolic acidosis is severe (controversial) or refractory (e.g. bicarbonate wasting). Bicarbonate should not be given if the pCO2 is elevated as the pH will not change (according to the above formula, a metabolic acidosis is merely being replaced by a respiratory acidosis).

G. Metabolic Alkalosis: (e.g. HCO3 > 28 mmol/L or B.E. > plus 4.0 mEq/L, pH > 7.40) This occurs where the plasma HCO3 or base excess is abnormally high. Causes include hypochloraemia (the level of bicarbonate and chloride in plasma are reciprocally related), which may be due to diuretic therapy or upper gastrointestinal obstruction (e.g. pyloric stenosis). The baby may also be trying to compensate for a respiratory acidosis, although the pH will never become alkalotic (as the baby will never over-compensate). The treatment of a metabolic alkalosis is to treat the underlying cause (e.g. chloride replacement) or the underlying cause of the respiratory acidosis.

H. Base Excess: This is one way of looking at the metabolic component. It refers to the 'amount of base that would have to be added to one litre of the baby's blood at 40 mmHg pCO2 to return the pH to normal. It is a calculated value and will be erroneous if the pCO2 is not normal. In these circumstances, the 'metabolic' component of the blood gas should be assessed using the plasma HCO3 level.

I. Acid-Base Disorders: Any one of the above four scenarios can occur in isolation, with or without compensation. These are classified as simple acid-base disorders. When a combination of simple acid-base disturbances occurs, the baby has a mixed acid-base disorder. When there is a mixed disorder, it is sometimes difficult to know which is the primary and which is the compensatory component. In such circumstances a helpful principle is that normal physiological processes never over-compensate. The pH can be relatively normal in the following situations - respiratory acidosis with metabolic compensation - metabolic acidosis with respiratory compensation - metabolic alkalosis with respiratory compensation - respiratory alkalosis with metabolic compensation The fourth is extremely unusual in neonates.

G. The Blood Gas Machine: This measures pH, pCO2 and pO2 and may measure glucose and lactate. It calculates HCO3, base excess and oxygen saturation. Measurements that are inaccurate, including Hb and oxygen saturation, should not be used to decide therapy (although newer machines contain co-oximetry and are very accurate).

K. Areas of Uncertainty in Clinical Practice: The main controversy relates to the use of bicarbonate (HCO3) for the treatment of a metabolic acidosis a) There is no evidence that the correction of an acute metabolic acidosis improves survival or long term neurodevelopmental outcome. b) The extra pCO2 produced (in the above equation) can cross cell membranes and paradoxically worsen the intracellular acidosis (as it combines with intracellular water, and with the equation in reverse, produces excess H+, which can't cross back out). c) Sodium bicarbonate is hyper-osmolar and if given rapidly, particularly to premature babies, may cause intraventricular haemorrhage. d) The exact reference ranges for pH, pCO2, HCO3 and base excess will vary from unit to unit. The above ranges are given for practical demonstration only.

15

L. References: • •

Ganong WF. Review of Medical Physiology, 19th Ed. 1999, p. 697-704. Appleton & Lange, Stanford, Connecticut Taeusch HW, Ballard RA (Eds). Avery's Diseases of the Newborn 7th Ed. W.B. Saunders Company, Philadelphia. 1998

6. BLOOD PRESSURE A. B. C. D. E.

Introduction Method of Blood Pressure Measurement 'Normal' Blood Neonatal Blood Pressure Values Areas of Uncertainty in Clinical Practice References

A. Introduction: The recognition and treatment of hypotension are particularly important to avoid complications such as cerebral ischaemic injury or intraventricular haemorrhage. On the other hand, hypertension in the newborn is increasingly seen as a complication in infants with bronchopulmonary dysplasia and who are receiving steroid treatment. Arterial blood pressure (BP) is determined by: cardiac output peripheral vascular resistance In general hypotension indicates inadequate systemic blood flow or left ventricular output and therefore inadequate tissue perfusion, although this is not always the case.

B. Method of Blood Pressure Measurement: Unless the baby has an in-dwelling arterial line, the only reliable and accurate way of measuring blood pressure indirectly is by using the oscillometric method (e.g. Dynamap). To minimise errors of noninvasive BP measurements, the following guidelines are recommended: cuff width to arm (or calf) circumference ratio as indicated on cuff if possible, obtain BP measurement during quiet or sleep state obtain average of two or three measurements if making management decisions use mean BP to monitor changes as less likely to be erroneous noninvasive BP may overestimate BP measurements in VLBW To minimise errors when using in-dwelling arterial lines, the following factors should be noted: narrow catheters will underestimate systolic BP occlusion of the tip of the catheter (vessel wall or clot) may dampen wave and underestimate BP even small air bubbles may have an effect on measurement peripheral lines read higher than umbilical lines

C. 'Normal' Blood Neonatal Blood Pressure Values: Blood pressure increases with: gestation birth weight postnatal age There is no significant difference between arm and calf blood pressure in normal infants. It is difficult to define 'normal' BP values in ELBW infants.

16

In clinical practice, the infant's blood pressure is generally considered to be adequate as long as urine output (> 1ml/kg/hr) and capillary refill (< 3 seconds) are within normal limits and there is no metabolic acidosis. However, these are not reliable indicators of tissue perfusion. Arbitrary definitions of hypertension are as follows: term infant: systolic > 90 mmHg, diastolic > 60 mmHg preterm infant: systolic > 80 mmHg, diastolic > 50 mmHg

Low birthweight infants

Birthweight (g) Systolic range (mmHg) Diastolic range (mmHg)

501-750

50-62

26-36

751-1000

48-59

23-36

1001-1250

49-61

26-35

1251-1500

46-56

23-33

1501-1750

46-58

23-33

1751-2000

48-61

24-35

Preterm infants

Gestation (wk) Systolic range (mmHg) Diastolic range (mmHg)

<24

48-63

24-39

24-28

48-58

22-36

29-32

47-59

24-34

>32

48-60

24-34

Preterm infants

Day

Systolic range (mmHg)

Diastolic range (mmHg)

1

48-63

25-35

2

54-63

30-39

3

53-67

31-43

4

57-71

32-45

5

56-72

33-47

6

57-71

32-47

7

61-74

34-46

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Term infants

Age

Systolic (mmHg)

Diastolic (mmHg)

Mean (mmHg)

1 hour

70

44

53

12 hour

66

41

50

Day 1 (Asleep)

70+/-9

42+/-12

55+/-11

Day 1 (Awake)

71+/-9

43+/-10

55+/-9

Day 3 (Asleep)

75+/-11

48+/-10

59+/-9

Day 3 (Awake)

77+/-12

49+/-10

63+/-13

Day 6 (Asleep)

76+/-10

46+/-12

58+/-12

Day 6 (Awake)

76+/-10

49+/-11

62+/-12

Week 2

78+/-10

50+/-9

Week 3

79+/-8

49+/-8

Week 4

85+/-10

46+/-9

D. Areas of Uncertainty in Clinical Practice: Definitions of 'normal' blood pressure in low birthweight and preterm infants are based on small numbers. Although these are 'healthy' infants, a variety of devices have been used to produce the measurements. There is very good evidence to suggest that blood pressure cannot necessarily be equated with normal systemic flow or a normal circulating blood volume.

E. References: • • •

Nuntnarumit P, Yang W, Bada-Ellzey HS. Blood pressure measurements in the newborn. Clin Perinatol 1999;26:981-996 Rennie JM, Roberton NRC (Eds). Textbook of Neonatology, 3rd Ed. Churchill Livingstone, Edinburgh, 1999. Taeusch HW, Ballard RA. Avery's Diseases of the Newborn 7th Ed. W.B. Saunders Company, Philadelphia. 1998

Other Reading/Web links • •

Bauer K, Linderkamp O, Versmold. Systolic blood pressure and blood volume in preterm infants. Arch Dis Child 1993;69:521-2 Kluckow M, Evans, N. Relationship between blood pressure and cardiac output in preterm infants requiring mechanical ventilation. J Pediatr 1996;129:506-12

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7. BOWEL OBSTRUCTION A. B. C. D. E. F. G. H. I. J.

Summary Introduction Differential Diagnosis Duodenal Atresia Midgut Malrotation and Volvulus Jejunoileal Atresia Meconium Ileus Hirschsprung’s Disease Investigation of Bowel Obstruction Management

A. Summary: -

delay in carrying out surgery may result in the loss of large amounts of bowel not all infants with bowel obstruction require transfer by the NETS team. Infants diagnosed early and without fluid or electrolyte problems may be safely transferred with local ambulance services. However, it is advisable to discuss such infants with the receiving hospital or the NETS team

B. Introduction: Signs of bowel obstruction can include:

-

vomiting with or without bile stained material, therefore never ignore bile-stained vomiting in the newborn gastric residuals before feedings failure to pass meconium in the first 24 hours of life abdominal distension (particularly with low level obstruction)

C. Differential Diagnosis: •

•

•

-

Intestinal obstruction without bilious vomiting: duodenal atresia (if obstruction proximal to Ampulla of Vater – 20% of cases) duodenal stenosis annular pancreas pyloric stenosis (usually presents at 4-6 weeks of life but may present as early as the first week) Intestinal obstruction with bilious vomiting: malrotation and volvulus duodenal atresia (if obstruction distal to Ampulla of Vater – 80% of cases) jejunoileal atresia meconium ileus necrotising enterocolitis (see Necrotising Enterocolitis) Intestinal obstruction with marked abdominal distension: ileal atresia Hirschsprung disease meconium ileus meconium plug imperforate anus

D. Duodenal Atresia: Duodenal atresia may take the form of either a membranous or interrupted-type lesion at the level of the papilla of Vater. In 80% the papilla of Vater opens into the proximal duodenum causing the vomiting to be bilious:

-

obstruction due to failure of recanalisation of the 2nd part of the duodenum during foetal development occurs in 1:5,000-10,000 live births commoner in males associated with Down syndrome in 25% hydramnios is seen antenatally X-ray usually shows a characteristic "double-bubble" appearance

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E. Midgut Malrotation and Volvulus: -

-

most patients with midgut malrotation develop volvulus within the first week of life bilious vomiting is the initial symptom and abdominal distention minimal until at a late stage bowel can be involved in strangulation at any time and age. Once midgut ischaemia occurs, unstable haemodynamics, intractable metabolic acidosis and necrosis with perforation develop malposition of the superior mesenteric vessels demonstrated by ultrasound examination is diagnostic upper gastrointestinal contrast studies should be performed by experienced practitioners only. Features include: • obstruction at the second portion of the duodenum • spiral configuration of the jejunum or a duodenojejunum that occupies the right hemi-abdomen symptomatic infants require immediate surgery

F. Jejunoileal Atresia: -

caused by a mesenteric vascular accident during fetal life abdominal distention with bilious vomiting is observed within the first 24 hours after birth. The more proximal the lesion, the earlier the bile-stained vomiting X-ray shows air-fluid levels proximal to the lesion. Calcification due to meconium peritonitis may be present

G. Meconium Ileus: -

-

-

thick tenacious meconium in the bowel (ileum, jejunum or colon) causes obstruction 50% have associated: • volvulus • jejunoileal atresia • bowel perforation and/or meconium peritonitis meconium ileus occurs in 15% of newborns with cystic fibrosis, and at least 90% of patients with meconium ileus have cystic fibrosis presentation includes: • early marked bowel distension • bilious vomiting • remarkable abdominal distention, tenderness and/or erythema of the abdominal skin may indicate perforation • on rectal examination mucus plugs may be evacuated after withdrawal of the examination finger (fifth finger) X-ray shows: • distended loops of intestine with thickened bowel walls • a large amount of meconium mixed with swallowed air produces the so-called "ground-glass" sign typical of meconium ileus, a characteristic feature but often absent • calcification, free air or very large air-fluid levels suggest bowel perforation

Patients with uncomplicated meconium ileus may be successfully treated with hypertonic enemas performed while adequate intravenous fluid is maintained. Immediate surgery is indicated for infants with complicated meconium ileus or where conservative treatment fails.

H. Hirschsprung’s Disease: -

-

causes 15-20% of newborn intestinal obstructions 80% of cases present in the first 6 weeks of life 4:1 male:female ratio presents with failure to pass meconium in the first 24 hours plus gradual onset of abdominal distension and vomiting. Distal short segment disease can present later in life with persistent and progressive constipation the most serious complication is enterocolitis. This occurs as a result of progressive colonic dilation with decreased ileal and colonic fluid resorption, stasis with bacterial overgrowth and mucosal ischaemia which may lead to massive acute fluid loss into the bowel with diarrhoea, shock and dehydration. Enemas should be avoided during episodes of enterocolitis because of the possibility of perforating the colon definitive diagnosis is made by a full thickness rectal biopsy showing a lack of ganglion cells in the myenteric plexus of the colon

20

I. Investigation of Bowel Obstruction: -

thorough physical examination and assessment of the circulation bowel obstruction may be a part of multiple anomalies, therefore look for associated abnormalities eg Vertebral Anal Cardiac Tracheo–Esopageal atresia Renal Limb (VACTERL) sequence with imperforate anus, trisomy 21 with duodenal atresia plain abdominal X-rays contrast studies and ultrasound examinations are best undertaken in centres with paediatric surgical services

J. Management: -

place infant in an incubator for close observation and temperature control nurse supine or on the right side with the head elevated place an orogastric tube (8 - 10FG) on low pressure suction (or aspirate with a syringe every 60 minutes and leave on free drainage). The amount and type (eg bile-stained, faeculent) of fluid aspirated should be recorded place nil by mouth commence IV fluids. Give maintenance fluids plus ml for ml replacement of NG aspirate with normal saline obtain abdominal x-rays (include supine and erect or decubitus view). Note that a relatively gasless abdomen is compatible with mid-gut volvulus consult with a paediatric surgeon or NETS to arrange transfer to an appropriate surgical centre it may be appropriate to commence antibiotics preferably after blood culture taken(discuss with the receiving unit or NETS) obtain blood for FBE, electrolytes, blood grouping and hold for X match (and blood cultures if commencing antibiotics) frequently, these infants have associated problems of acidosis and shock

8. BREASTFEEDING ISSUES A. B. C. D. E. F. G. H. I. J. K. L. M. N. O. P.

Summary Introduction Benefits of breast milk Storage of Breast milk for Infant Use Maintenance of supply of breast milk Developmental issues Prematurity and nutritional adequacy of human milk Human Milk Fortifier Breast milk substitutes Infections Maternal medications Drugs of addiction Herbal preparations Jaundice Drugs in pregnancy and/or lactation References

A. Summary: -

Breast milk is the milk of first choice in neonates, whether term or preterm there are significant clinical benefits to providing breast milk in the preterm infant expressed breast milk can be safely frozen for later use human milk fortification should be considered in babies < 1500g or < 30 weeks' gestation very few maternal medications contraindicate breastfeeding maternal Hepatitis C does not preclude breastfeeding (unless nipples are cracked)

B. Introduction: The Innocenti Declaration (WHO/UNICEF, 1990) recognised that breastfeeding is a unique process that provides ideal nutrition for infants and contributes to their healthy growth and development. The Paediatrics and Child Health Division of the Royal Australasian College of Physicians encourages and supports the promotion of breastfeeding (see website).

21

C. Benefits of breast milk: •

-

• • •

The many benefits of mother's own milk are well known. Breastmilk is a unique 'living" fluid. It contains: anti-infective factors hormones enzymes specialised growth factors anti-inflammatory mediators specific nutrients Colostrum is a high density; low-volume feed high in immunoglobulins, which evolves into mature milk between 3 and 14 days postpartum. Breastmilk feeding for both preterm and unwell term infants assists recovery and has major health benefits. As the unwell or preterm infant may not be able to breastfeed mothers are encouraged to provide fresh expressed milk daily; if this is not possible breast milk can be stored in a refrigerator or freezer.

D. Storage of Breastmilk for Infant Use: Guidelines for collecting and storing breast milk are more stringent for sick and preterm babies than for healthy babies at home. - sterilised containers are recommended - refrigeration at 40C for 48 hours results in minimal loss of nutrients and bacterial count is reduced - freshly expressed milk should be chilled in refrigerator before adding to frozen milk - thaw breast milk by placing in cool or warm water - thawed milk should be used within 24 hours - never refreeze or re-warm breast milk

Time to keep milk in various conditions

Breast milk

Room Temperature Refrigerator

Freezer

Freshly expressed into closed container

6 - 8 hours (d260C ) If refrigeration is available store milk there

3 - 5 days (d40C) Store in back of refrigerator where it is coldest

2 weeks in freezer compartment inside a refrigerator 3 months in freezer section of refrigerator with separate door 6 - 12 months in deep freeze (- 180C)

Previously frozen thawed in refrigerator but not warmed

4 hours or less i.e. next feeding

Store in refrigerator 24 hours

Do not refreeze

Thawed outside For completion of refrigerator in warm water feeding

Hold for 4 hours or until Do not refreeze next feeding

Infant has begun feeding

Discard

Only for completion of feeding then discard

Do not refreeze Discard

There is controversy regarding the use of sterile vs clean washed containers for storage of expressed breast milk (EBM) intended for preterm infants. There is limited published evidence to support the use of clean containers One Level 3 nursery in Melbourne does provide sterile containers which families re-use after washing in the dishwasher and air-drying.

E. Maintenance of supply of breast milk: •

-

The long-term commitment of expressing breast milk for a preterm infant is stressful and may result in reduced volumes of EBM. Strategies that assist in maintaining a good supply of milk include: the provision of a comfortable environment within the special care nursery if expression at the cotside is impractical reminders that it is the regular emptying of the breasts that stimulates formation of more mature milk the continuing discipline of expressing at least once overnight to ensure the longevity of supply kangaroo care (the practice of mother holding her baby skin to skin between her breasts). The close contact triggers

22

•

the enteromammary pathway by which a mother produces antibodies in response to antigens in the infant's environment If supply lags, technique and frequency of expression needs review before resorting to galactogues. Commencement of an oral contraceptive agent may also contribute to reduction in supply. In addition

Galactogues: These are substances, which stimulate the supply of breast milk. Both pharmacological and herbal preparations are available. - Published evidence supportive of herbal preparations is limited. Fenugreek is the most widely recognised however there is no data regarding transmission in breast milk or safety for preterm infants. - Metoclopramide (Maxalon) will stimulate breast milk supply in the lactating mother. The safety of this medication has been established for preterm infants. Mothers should be advised about the possibility of dystonic reactions. In some women use exacerbates symptoms of depression. Controversy exists over the dosage regime and duration. A suggested regime is 10mg tds for 5 days and then tapering over the next 5 days. Some women benefit from repeated courses but little data exists on the safety of such practice. Metoclopramide often results in dramatic increase in supply, which may not be sustained once medication is withdrawn. - Domperidone also acts a galactogue and is safe for preterm infants. There appears to be a slower onset of action but the increase in supply is better maintained than with Metoclopramide. Unfortunately Domperidone is not approved as a galactogue on the Australian Pharmaceutical Benefits Scheme and the quantity required can prove costly. The dose required is 10 - 20 mg qid. Domperidone is better tolerated by mothers as a long term stimulant of breast milk supply.

F. Developmental issues: Initiating breast-feeding in preterm infants does not require a demonstrated ability to breastfeed. Kangaroo care is a good introduction to mother's breasts for the preterm or unwell infant. Studies have shown that preterm infants show greater cardio-respiratory stability when breast feeding than bottle feeding. Infants exhibit sucking movements as early as 11 weeks gestation. By 32 weeks there is coordination of sucking and swallowing, but this is not sustained until closer to term. Controversy exists over the issue of nipple confusion. Ultrasonography has shown that the sucking action used at the breast is different from that used for an artificial teat. A randomised controlled trial comparing artificial teats and cup feeding in preterm infants did not demonstrate any difference in time to achieve breastfeeding. (personal communication). If it is to be mentioned then the technique of cup feeding needs brief explanation Similarly controversy exists between the advantages of indwelling naso-gastric feeding tubes and intermittent orogastric tube feeds. Sandra Lang in her book "Breastfeeding Special Care Babies" addresses these issues in depth.

G. Prematurity and nutritional adequacy of human milk: Preterm breast milk differs from term milk, not only in nutritional composition but also in immuno-protective factors. Preterm infants given breast milk have significantly reduced rates of sepsis and necrotising enterocolitis compared with infants fed breast milk substitutes. Preterm infants exclusively breastfed have been found to have an IQ several points greater than infants fed breast milk substitutes. Is this difference real world significant? Should the degree of difference be stated? Mother's own milk may not meet the increased nutritional demands of the preterm infant whose birthweight is below 1500g. These needs persist to term postmenstrual age. There is considerable variation in the energy content of expressed breastmilk largely due to separation of the fat whilst standing. Use of hind-milk, with a two to threefold greater fat content than foremilk will provide significantly more energy for growth. The content of protein and sodium declines throughout lactation. Calcium and phosphorous content is also insufficient for the growing preterm infant.

H. Human Milk Fortifier: Mother's own milk can be supplemented by combining with a commercially prepared fortifier to provide increased protein, energy and minerals. All human milk fortifiers contain similar amounts of protein, energy, calcium and phosphorous. The differences relate to the type of protein and the amounts of lactose, sodium and vitamins. Dr K Simmer has prepared comparative tables indicating the composition of breast milk and fortifiers available in Australia. In general infants with a birthweight less than 1500g and less than 30 weeks gestation will benefit from addition of fortifier, which should continue to discharge, when the infant is not breastfeeding. In practice fortification of breast milk is best delayed until the infant demonstrates tolerance of a reasonable volume of enteral feeds (150 mls/kg/day). Breast milk fortification is often commenced at half strength for 2 days and if tolerated full strength

23

supplementation is introduced. However, there are a number of potential complications with fortification. These include:

-

an increase in regurgitation an increase in feed intolerance glycosuria in extremely of preterm infants hypercalcemia in extremely preterm infants

As the fortifier is usually cow's milk based there is a theoretical advantage in using a product in which the protein has been hydrolysed. Infants fed fortified human milk receive less volume, but greater intakes of protein and minerals and experience greater weight gain and incremental linear growth than infants fed unfortified milk. The growth of infants fed fortified breastmilk is still less than infants fed on preterm formula. However the quality of the milk and its many advantages far outweigh any growth disadvantage. In general, fortifier can be discontinued once the infant reaches a corrected age of term and prior to discharge from hospital.

I. Breast milk substitutes: When there is insufficient breast milk available for an infant tolerating enteral feeds parents should give consent for the use of formula. If the intention is to primarily breastfeed then use of a protein hydrolysed or semi-elemental formula may be appropriate. If the infant is not tolerating full volume feeds then the formula should be standard 67 kcal per 100 mls. Most preterm formulae are 85 kcal per 100mls and are fed once the infant is tolerating volumes of 150mls/kg/day as they provide better nutrition. Dr K Simmer has prepared comparative tables indicating the composition of preterm formulae available in Australia. Donor human milk is not an option as there are no human milk banks in Australia. In general, preterm formulas can be discontinued once the infant reaches a corrected age of term and prior to discharge from hospital.

J. Infections: -

-

-

Maternal HIV is the only infection in which breastfeeding is contra-indicated in the developed world Hepatitis C has been reported to have a 5% risk of transmission. Most probably this occurs at times of active disease (PCR positive women). It is generally advised that HCV positive mothers do not breastfeed when nipples are cracked. Hepatitis B is not transmitted through breast milk CMV is transmitted through breast milk. The burden of disease acquired from breast milk is not well established. It is presumed that preterm infants are more vulnerable and likely to exhibit more severe clinical illness, such as pneumonitis, than term infants. However women who are CMV positive are not discouraged from breastfeeding as the other benefits are thought to outweigh the risk. Herpes Simplex is not transmitted through breast milk. Should there be an open sore on the breast the mother would be advised to avoid feeding from that breast. With Varicella and Herpes Zoster (shingles) maternal antibodies transmitted through breast milk will be protective. However in the case of Varicella if the mother develops chicken pox within 5 days of birth the infant is at risk and should be protected with VZV immunoglobulin. Breast-feeding can then continue, provided there are no lesions on or near the nipple. (link) bacterial infections almost never transmit disease through breast milk

K. Maternal medications: -

absolutely contraindicated: • chemotherapeutic agents

•

-

radioactive drugs

relatively contraindicated: • lithium

•

citalopram

•

cyclosporin

Most psychoactive medications are now generally considered safe, although dosage needs to be considered. Infants should always be carefully monitored for effects of sedation when their mother's are using psychoactive drugs. Be aware that drug companies are very cautious in their recommendation of safety for the breastfed infant. Preferably consult specific reference texts or drug advisory services experienced in lactation.

24

L. Drugs of addiction: Methadone passes in small quantities into breast milk and generally the benefits of breast milk overcome the disadvantages. In situations of very high maternal dosage (e90mg daily) the infant is at risk of sedation. Buprenorphine is a long acting narcotic agonist and antagonist used to replace methadone in opiate addicts. Little information is available regarding the pharmacology of this drug in lactation. Sedative effects are of concern. Marijuana passes into breast milk and the relative dose is concentrated. Infants are at risk of sedation, feeding difficulties and poor weight gain.

M. Herbal preparations: Scientific data is limited. Given the variability in standards of preparation of herbal supplements it is recommended that breastfeeding mothers avoid such products.

N. Jaundice (see also Jaundice in the first two weeks of life): Increased rates of initiating breastfeeding have resulted in an increased incidence of jaundice. There is an inverse correlation between the number of breastfeeds per day and level of jaundice. Increasing the number of breastfeeds per day from 6 to 12 per day for each of the first 3 days of life results in significantly lower serum bilirubin on day 3. Increased number of feeds is associated with significantly greater daily milk intake, better elimination of meconium and thereby reduced entero-hepatic circulation. Commencement of phototherapy should be seen as an opportunity to review breastfeeding frequency and technique. It is not carte blanche to introduce supplemental formula feeds. Preferably mothers will be encouraged to express after feeding and top-up their babies with their own milk rather than formula. Excessive use of formula runs the risk of reducing milk supply, as the infant is less stimulated to empty the breast.

O. Drugs in pregnancy and/or lactation: • •

Medications and Mother's Milk. T Hale. 10th edition, 2002. Pharmasoft publishing, Texas. Drugs in Pregnancy and Lactation. Briggs G et al. 6th edition 2002. Lippincott Williams and Wilkins.

Q. References: • • • • • • • • • • • • • • • • •

J Akre. Infant Feeding: the physiological basis. WHO 1994. Bulletin (Suppl.) 67:25 J Akre. Infant Feeding Guidelines for Health Workers. 1996. NHMRC Sosa R, Barness L. Bacterial growth in Refrigerated Human Milk. Am J Dis Child. 1987: 141; 111-112 Whitelaw A. Kangaroo baby care: just a nice experience or an important advance for preterm infants? Pediatrics 1990; 85: 604-605 Ehrenkranz RA et al. Metoclopramide effect on faltering milk production by mothers of premature infants. Pediatrics. 1986;78:614-20. Da Silva et al. Effect of Domperidone on milk production in mothers of premature newborns: a randomised, double-blind, placebo controlled trial. CMAJ. 2001; 164: 17-21. Blaymore Bier JA et al. Breastfeeding infants who were extremely low birth weight. Pediatrics 1997;100:E3 Lang S. Breastfeeding Special Care Babies. 1997. Bailliere Tindall. London. Schanler RJ, Hurst NM, Lau C. The use of human milk and breastfeeding in premature infants. Clin Perinatol. 1999;26:379 - 398 El-Mohandes AE et al. Use of human milk in the intensive care nursery decreases the incidence of nosocomial sepsis. J Perinatol. 1997;17:130 - 134 Lucas A, Cole TJ. Breast milk and necrotising enterocolitis. Lancet. 1990; 336: 1519-1523 Lucas A, Morely R, Cole TJ et al. Breastmilk and subsequent intelligence quotient in children born preterm. Lancet. 1992; 339:261-264 K Simmer. Choice of formula and human milk supplement for preterm infants in Australia. J Paediatr Child Health. 2000;36:593-595. Ruff. Infection and breastmilk. Semin Perinatol. Howard CR, Lawrence RA. Drugs and breastfeeding. Clin Perinatol. 1999;26: 447 - 478 Maisels MJ, Gifford K. Normal serum bilirubin levels in the newborn and the effect of breastfeeding. Pediatrics. 1986;78:837-843 De Carvalho M, et al. Frequency of breastfeeding and serum bilirubin concentration. Am Dis Child 1982;136:747-748 Clinical Aspects of Human Milk and Lactation. Clin Perinatol June 1999;26:2

25

9. BRONCHOPULMONARY DYSPLASIA A. B. C. D. E. F. G. H. I. J. K.

Summary Introduction Risk Factors Clinical Features Management of BPD in Level 3 Units Respiratory Criteria for Transfer to a Level 2 Hospital Management in the Level 2 SCN Oxygen Home oxygen Follow up References

A. Summary: -

the most severely affected babies are the most premature, particularly 23-26 week gestation babies diuretics and corticosteroids are effective in achieving short-term improvement in the status of ventilator dependant babies. Safety issues of steroid use are unresolved. There is no place for long term therapy with diuretics in level 2 SCN's there is no consensus on how to wean oxygen in babies with BPD the transition from a tertiary hospital nursery to a level 2 SCN is a difficult time for parents as they adjust to different staff and practices

B. Introduction: In line with the recommendations from a recent workshop in North America the term bronchopulmonary dysplasia (BPD) will be used in this chapter rather than Chronic Lung Disease. The definition is complicated, however in this chapter BPD refers to a premature baby who has been in oxygen for > 28 days. BPD is the single most important factor determining length of stay in babies born at less than 29 weeks. The most severely affected babies are the most premature, particularly 23 - 26 week gestation babies.

C. Risk Factors: -

prematurity peripartum inflammation/infection associated with preterm labour and/or clinical or subclinical chorioamnionitis postnatal lung Injury due to volutrauma, oxygen or infection

D. Clinical Features: Tertiary unit babies with BPD (actual or evolving) fall into three broad groups:

-

babies dependant on endotracheal mechanical ventilation (MV) babies dependant of Nasal CPAP babies who are oxygen dependant, usually by nasal prongs

The most common clinical scenario is the 23 - 26 week gestation baby who, over a period of 4 - 10 weeks, progresses from MV, NCPAP through to requiring supplementary oxygen. These babies are usually transferred to a level 2 Special Care Nursery (SCN) for ongoing care. Although some of these babies spend many weeks on NCPAP it is common to see rapid improvement in their respiratory stability once weaned from NCPAP. Respiratory stability off NCPAP is the single most important criterion that determines suitability for transfer to a SCN. It is important to understand the tertiary unit's experience with babies at these gestations as it has a significant impact on decision making with respect to transfer to level 2 SCNs. Issues include:

-

all tertiary units experience late deaths of extremely premature babies due to chronic lung disease when prolonged MVis needed there are often many weeks before one can reassure the family with confidence that the baby is likely to survive. Once a baby is showing consistent growth associated with an oxygen requirement less than 40% the recovery process is likely to be successful some babies cope for many months on NCPAP in high (more than 40%) oxygen concentrations before dying. Fortunately this group is rare

These factors make the care of babies with BPD extremely demanding for babies and their families, as well as for nursing, medical and ancillary staff.

26

E. Management of BPD in Level 3 Units: 1. Respiratory support:

-

-

-

there is an intense focus on minimizing ventilator associated lung injury from the moment a baby is placed on a ventilator. Synchronised modes of MV with close monitoring of tidal volumes are key features of current practice. In addition there is a more liberal approach to carbon dioxide control, allowing CO2 to rise into the 50's and 60's providing the pH remains better than 7.25 oxygen damages delicate lung tissue as well as the immature retina. Pulse oximetry targets are typically setx etween 88 to 93% in the first weeks after birth endotracheal ventilation is being increasingly replaced by NCPAP, even for the tiniest babies while it is clear that the aggressive early use of NCPAP can avoid the need for endotracheal intubation and MV in babies who in the past would have been electively intubated, it is not yet clear what the effects of this practice are on survival and short and long term morbidity. Randomised trials are in progress to determine best practice in this area babies who require endotracheal ventilation are aggressively weaned and extubated to NCPAP often within 1-2 days of birth

2. Drug Therapy for established/evolving BPD:

-

Corticosteroids:

• • • • • • • •

-

dexamethasone is effective in achieving short-term improvement in the status of ventilator dependant babies there is now low level evidence showing that dexamethasone in the first week of life is associated with an increased risk of cerebral palsy in survivors safety of corticosteroids used later in the course of evolving BPD between 14 - 28 days is unresolved. RCT's are in progress frequency of the use of steroids for BPD in NICUs has dramatically declined in the past 2 years it is recommended that corticosteroids be used only within the context of a RCT. Otherwise a "low" dose regimen (eg 0.15 - 0.25mg/kg/day) weaned and ceased over a 7 - 10 day period is recommended typical clinical scenarios where steroids would be considered are a baby > 2 weeks of age who is unable to be weaned from endotracheal MV there is no place for the use of steroids in the treatment of BPD outside a tertiary neonatal unit early use of inhaled steroids is ineffective in preventing BPD

Diuretics:

• • • • • • •

insufficient studies of suitable size reporting on important outcomes exist to strongly support the use of diuretics for the treatment of BPD diuretics are an effective short term therapy for ventilated babies There is no evidence for efficacy in non ventilated babies therefore diuretic therapy should be weaned and ceased once babies are stable off mechanical ventilation typical combinations include hydrochlorothiazide and spironolactone chronic frusemide administration is generally avoided, as it has been associated with the development of nephrocalcinosis and hyperchloremic metabolic alkalosis NaCl and KCl supplementation are commonly required there is no place for long term therapy with diuretics in level 2 SCN's

3. Nutrition:

-

provision of adequate calories in a nutritionally appropriate form is critical caloric requirements of babies with moderate to severe lung disease can be as high as 130 - 150 calories/kg/day babies are modestly fluid restricted (150 - 160mL/kg/day) and fed fortified breast milk or low birthweight formula growth is closely monitored and caloric intake titrated against growth Vitamin A supplementation has a statistically significant benefit in reducing oxygen requirements at 36 weeks corrected gestational age however most consider this effect to be clinically insignificant babies sufficiently stable to transfer to a level 2 unit should not require a caloric density of > 24 cal/30mls

27

4. Oxygen Therapy:

-

-

oxygen is the one constant in the treatment of BPD but it has been poorly studied once weaned from NCPAP, oxygen is delivered by nasal prongs using low flow (<0.5L/min) there is no consensus on how to wean oxygen in babies with BPD weaning is dictated to some extent by the equipment available. Some tertiary centres have only recently moved from having flow meters with a lower limit of 0.25L/min/O2. Other units use flow meters that allow weaning down to as low as 0.005mL/min/O2. Most believe that weaning should be slow, but what this means varies from institution to institution babies with BPD have a degree of pulmonary hypertension, and are therefore likely to benefit from a more generous oxygen administration regimen rather than from a restrictive policy. Whilst there is some logic to this approach, there is indirect evidence from randomized controlled trials conducted for other reasons suggesting that a more liberal oxygen policy in these babies can actually increase the pulmonary morbidity. RCT's are in progress to address this question

F. Respiratory Criteria for Transfer to a Level 2 Hospital: -

minimum of 7 days off respiratory support including NCPAP or "high flow"(1-2L/min) subnasal oxygen infrequent (1-2/day) apnoeas/bradycardias that require no or minimal stimulation for recovery consistent, stable saturation in the range 93-97% on ‹ 0.5L/min subnasal oxygen, or 35% headbox oxygen not receiving corticosteroids for BPD preferably the baby should not be diuretic dependant for respiratory stability consistent growth on 2-3 hourly bolus feeds with a caloric density no more than 24 cals/30mls there is a small number of babies with severe but nonNCPAP dependant BPD who are transferred to level 2 units. These are a specific group of babies where the decision to transfer and the principles of ongoing medical management require an individualised management plan worked out between referring and receiving Consultant Medical staff, preferably in collaboration with a Paediatric Thoracic Consultant. The principles of care of such babies is beyond the scope of this chapter

G. Management in the Level 2 SCN: •

•

•

The transition from a tertiary hospital nursery to a level 2 SCN is a difficult time for parents as they adjust to different staff and practices. Both tertiary and level 2 staff should be proactive in anticipating and addressing these issues. If the referring Neonatologist believes a particular approach should be considered for a particular baby, this should be discussed with the receiving Paediatrician directly so that a consistent message goes to the parents. It is common in Victoria for level 2 SCN's to have oxygen flow meters that do not permit accurate delivery of subnasal oxygen below 0.25L/min. Parents must be educated about this in advance so they do not see the increased FiO2 dose as "wrong" or "bad" therapy or as an indication their baby has deteriorated. Clearly Victoria needs to work towards a consistent approach to equipment such as oxygen flow meters as the current system is illogical and confusing. It is strongly recommended that these babies to be nursed in the SCN rather than the Paediatric ward even if post term corrected age. This should reduce the risk of developing nosocomial infection particularly respiratory viral infections.

Nutrition:

-

Aim to achieve an intake of 180mls/kg/day Breast milk fortifier or a low birthweight formula can be continued until at least term without adverse effects if caloric supplementation is required For babies on tube feeds oral feeds should be cautiously introduced eg. initially one oral feed/day then 2 etc as the baby copes with the previous increment

H. Oxygen: 1. General considerations:

-

Aim to move to intermittent oximetry rather than continuous once it is clear the baby is not having apnoea or bradycardia Saturation goal should be 93-98% Brief periods where the saturation drops to the low 90's are not of concern During feeding and certain parts of sleep are the times where a baby's oxygen demand is higher. Therefore if one is looking to see if a baby will manage in less oxygen saturations should be monitored over several feed periods or for several hours during sleep

28

-

For babies in headbox/tent oxygen do not wean by more than FiO2 0.01 in a 24 hour period even if the saturations are 100% For babies on low flow subnasal oxygen do not wean by more than 10mls/24 hours If the lowest accurate flow deliverable is 0.25L/min then the only option is to periodically (eg twice/week) turn off the oxygen and carefully monitor the saturations Blood gas monitoring is not required in stable babies The indications for blood transfusion in a growing stable baby with a mild oxygen requirement are unclear and currently the subject of study, but most practice a conservative policy i.e accept Hb concentrations down to 8g/dl particularly if there is a good reticulocyte response

2. Ceasing oxygen:

-

A prolonged period (8-12 hours) of saturation monitoring should be undertaken that captures extended periods of sleep Babies with BPD should not be discharged until at least 72 hours after ceasing oxygen

I. Home oxygen: This will be the subject of a separate chapter, however some general points can be made.

1. Criteria for Home Oxygen – General:

-

Appropriate social/home environment including reasonable accessibility to medical care Baby is on 4 hourly or demand oral feeding regimen Baby is normothermic in an open cot Satisfactory growth All babies discharged from tertiary units on home oxygen have specific Paediatric Thoracic specialist follow up. It is strongly recommended that Paediatricians manage babies on home oxygen in collaboration with a Paediatric Thoracic physician

2. Criteria for Home Oxygen – Respiratory:

-

Baby must pass an "air test". The oxygen is turned off, the nasal prongs removed and the baby monitored over 30 minutes If saturations are maintained >86% for 30 minutes the test should be repeated in 48 hours. If a second test is satisfactory the baby is eligible for discharge on home oxygen on respiratory grounds. In other words the baby has demonstrated a reasonable level of respiratory reserve

J. Follow up: -

These babies require term follow up throughout childhood There is an increased pulmonary morbidity in the first 2 years of life. Parents should be counselled about this morbidity and ways to minimise it. Influenza vaccine is not officially recommended for these babies RSV prophylaxis is not routinely recommended

K. References: • • • • • • •

Jobe A, Bancalari E. Bronchopulmonary Dysplasia, NICHD/NHLBI/ORD Workshop Summary. Am J Respir Crit Care Med. 163 1723-1729, 2001 Barrington KJ and Finer NN. Treatment of Bronchopulmonary Dysplasia - A Review. Clinics in Perinatology 25 1 March 1998 177-202 Brion L et al. Diuretics acting on the distal renal tubule for preterm infants with (or developing) chronic lung disease. Cochrane Neonatal group, Cochrane database of systematic reviews, Issue 3, 2001. Shah V, Ohlsson A, Hallidah HL, Dunn MS. Early administration of inhaled corticosteroids for prevention of chronic lung disease in ventilated VLBW preterm neonates. Cochrane Neonatal group, Cochrane database of systematic reviews, Issue 3, 2001. Halliday HL and Ehrenkranz RA. Early postnatal corticosteroids for the prevention of chronic lung disease in preterm babies. Cochrane Neonatal group, Cochrane database of systematic reviews, Issue 3, 2001. Chronic Lung Disease. Department of Neonatal Medicine Protocol Book, Royal Prince Alfred Hospital, Sydney, NSW. www.cs.nsw.gov.au/rpa/neonatal Oxygen Therapy. Department of Neonatal Medicine Protocol Book, Royal Prince Alfred Hospital, Sydney, NSW. www.cs.nsw.gov.au/rpa/neonatal

29

10. CHICKENPOX (VARICELLA ZOSTER) A. Introduction B. Fetal exposure to Varicella Zoster Virus 1. Management 2. Areas of Uncertainty in Practice C. Infant of a mother with perinatal chickenpox 1. Management 2. Areas of Uncertainty in Practice D. Postnatal exposure to VZV (up to 28 days) 1. Management E. Reference

A. Introduction: The Varicella-zoster virus is a herpes virus causing chickenpox as the primary infection or herpes zoster after reactivation from its latent form in dorsal root ganglia.

B. Fetal exposure to Varicella Zoster Virus: -

Fetal varicella due to primary infection with chickenpox in pregnancy is usually benign Congenital varicella syndrome (CVS) is thought to result from in utero viral reactivation or disseminated zoster infection

Risk is higher when maternal chickenpox occurs before 20 weeks and is estimated at approximately 2%. CVS is associated with:

-

cicatricial skin lesions limb hypoplasia or paresis microcephaly (secondary to cortical atrophy) ophthalmic lesions (chorioretinitis, microphthalmia, atrophy and cataracts)

1. Management:

-

give ZIG (6mL IMI) within 72 hours of significant exposure to the pregnant woman if sero-negative or if there is a negative history and sero-testing is unavailable continue monitoring, including with ultrasound, since ZIG reduces the clinical attack rate in the pregnant woman but may not eliminate fetal risk negative amniotic fluid PCR correlates well with a good outcome but positive PCR correlates poorly with congenital varicella syndrome development

2. Areas of Uncertainty in Practice:

-

termination of pregnancy would not usually be offered but may require discussion

C. Infant of a mother with perinatal chickenpox: When maternal chickenpox develops within 7 days and up to 28 days after delivery the newborn is at risk of developing severe neonatal varicella (reported mortality rates of up to 30%) since the newborn will not have any passive immunity.

1. Management:

-

give the infant ZIG (2mL IMI) as soon as possible after delivery or onset of maternal illness. ZIG must be given within 72 hours while in hospital, a mother and/or infant with lesions should be isolated from other patients. A mother with lesions does not need to be isolated from her own infant continue to encourage breastfeeding unless lesions are on or near the nipple admit infant into hospital isolation room if rash develops give IV aciclovir (20mg/kg every 8hours) to infants who develop chickenpox and:

• • •

did not receive ZIG prophylaxis within 24 hours are immunocompromised are premature (less than 28weeks gestation at birth)

30

2. Areas of Uncertainty in Practice:

-

The high risk period for severe infection varies between authorities. These conservative recommendations follow the published Australian guidelines

D. Postnatal exposure to VZV (up to 28 days): Chickenpox is a common childhood illness so the commonest situation is of a sibling developing chickenpox. The risk to the infant relates to whether transplacental transfer of maternal antibody has occurred. Significant exposure includes face to face contact for more than 5 minutes, or contact for more than an hour with a person who has uncrusted lesions or develops them within the next 48 hours.

1. Management:

-

-

give ZIG (2mL IMI) immediately if: • mother is seronegative • her sero-status cannot be determined and history is negative • infant born at less than 28weeks gestation or <1000gm birthweight encourage normal care. Do not exclude infant from family contact admit for aciclovir treatment if infant becomes unwell

E. References: •

The Management of varicella-zoster virus exposure and infection in pregnancy and the newborn period A. Heuchan, D. Isaacs on behalf of the Australasian Subgroup in Pediatric Infectious Diseases of the Australasian Society for Infectious Diseases MJA 174 2001 288-291

11. CLEFT LIP AND PALATE A. B. C. D. E. F. G.

Summary Introduction Diagnosis Investigation Management Areas of Uncertainty in Clinical Practice References

A. Summary: -

early feeding intervention and education from a Speech Pathologist and a Lactation Consultant fosters establishment of an effective feeding regimen a dysfunctional feeding pattern may indicate other congenital anomalies when breast feeding a baby with a soft palate cleft, unilateral or bilateral cleft, supplementary breast milk feeding is usually required assisted feeding techniques are used with bottle feeding oromotor development, adequate nutritional intake, positive caregiver/infant interaction and consistent carers are necessary for effective feeding

B. Introduction: • • • •

Cleft lip and palate occurs in approximately 1 per 1000 births. This may occur sporadically or in the setting of a family history. Babies born with a cleft may present with a range of feeding difficulties according to the type and severity of the cleft, however, a direct relationship between cleft type and feeding problem does not seem to exist. Sucking efficiency varies but is reduced on both the bottle and breast. The baby is at risk of failing to thrive as oral intake efficiency is reduced and the baby fatigues during lengthy feeds.

C. Diagnosis: Obvious in more severe cases. Careful examination with a bright light and a tongue depressor is required in the case of a posterior soft palate cleft or submucous cleft of the palate. Difficulties in feeding may lead to a later diagnosis.

31

D. Investigation: A small percentage of affected children have abnormalities elsewhere in the face or in other systems.

E. Management: 1. Early:

-

genetic counselling and information about the Cleft Pals Association who can arrange a parent visit if appropriate feeding assessment by a Speech Pathologist within 24 hours of birth to discuss feeding options with the parents referral to a Lactation Consultant to discuss breast feeding and/or expressing techniques all mothers encouraged to put their baby to the breast for skin to skin contact, bonding and to maximise the opportunity to stimulate milk flow parental education about infant feeding cues:

•

Breast feeding: A cleft palate can interfere with breast feeding as it precludes generation of suction during feeding. Milk extraction from the breast is inefficient and the required strong attachment to the breast is absent. The potential for a baby with a cleft palate to receive adequate nutrition from being exclusively breast fed in the traditional manner is limited. Mothers wishing to breast feed should consult a lactation consultant for support as breast feeding an infant with an unrepaired cleft is demanding. When breast feeding a baby with a soft palate cleft, unilateral or bilateral cleft compressing the breast to express the milk into the babies mouth will facilitate milk flow and the baby's suck swallow reflex. As the necessary negative intra oral pressure for sucking will rarely be produced for adequate volume intake, a "top up" with expressed breast milk via a supply line or bottle will be required. However, breast feeding a baby with an incomplete cleft lip can be achieved by pressing part of the breast into the cleft to obtain lip seal.

•

Bottle feeding: Assisted breast milk feeding using squeezable bottles requires less support and intervention than using a rigid bottle, after initial instruction. A Haberman Feeder or Pigeon teat (cross cut) with a Cleft Pals or Soft Plas squeeze bottle are recommended. Before feeding, practice squeezing the bottle and compressing the teat to be familiar with rate of flow and pressure required. When feeding a baby with a cleft lip and palate, hold the baby in a semi upright position to minimise the nasal regurgitation of milk. Squeeze the bottle rhythmically only when the baby sucks (every two, three of five sucks). Burp the baby regularly as the cleft allows extra air to be ingested. The feed should be completed within 30-40 minutes.

-

Audiology:

•

-

Surgery (Plastic, ENT and Oral surgery):

• • • • • •

-

lip repair early or up to 3 months palate repair at approximately 6 months bone graft to the cleft alveolus (gum) 9-11 years ventilation tubes to ears at time of palate repair and subsequently adjustments of lip and nose shape as required until fully grown pharyngoplasty to improve speech age 5-6 years in 10-15% of patients with cleft palate

Dental, orthodontic and oral surgery:

• • •

-

regular testing during childhood until risk of effusion/ otitis media subsides, removing need for ventilation tubes

lifetime dental care orthodontics before and after alveolar (gum) bone graft jaw surgery to correct malocclusions in some teenagers

Speech therapy:

•

supervision as speech develops, therapy as required

32

F. Areas of Uncertainty in Clinical Practice: -

-

There is little evidence that currently used feeding methods improve feeding efficiency and outcomes. Feeding difficulties are reported in the literature but opinions vary on appropriate feeding strategies Palatal Obdurators The use of feeding plates is unsupported as they do not enable the infant to seal the oral cavity effectively and generate suction. However the firm palatal surface may assist the infant to stabilise and compress the nipple. The combined use of a palatal obdurator and lactation education may reduce feeding time, increase volume intake with increased flow rate but babies will still require supplementation. Nasogastric Tubes Infants with airway difficulties may require combined oral and tube feeds. Airway stability must be determined prior to oral feeding and feeding coordination should be the focus not the volume of the oral feed.

G. References: • • • • •

Converse, Plastic & Reconstructive Surgery Vol.4, p. 1930 Saunders Bannister P. Early Feeding Management. In:Watson ACH, Sell DA, Grunwell P (eds) .Management of Cleft Lip and Palate. London: Whurr; 2001 pp. 137-147. Clarren, SK. Anderson, B. Wolf, LS. Feeding infants with cleft lip, cleft palate, or cleft lip and palate. Cleft Palate Journal 1987 Jul; 24(3): 244-249. Glass RP, Wolf LS, Feeding Management of Infants with Cleft Lip and Palate and Micrognathia. Inf Young Children. 1999; 12(1): 70-81. Shaw WC, Bannister RP, Roberts CT, Assisted feeding is more reliable for infants with clefts- a randomised controlled trial. Cleft Palate Craniofacial J. 1999; 36(3):262-8.

12. COMMON LIMB PROBLEMS A. B. C. D. E.

Summary Introduction Upper Extremities Lower Extremities References

A. Summary: -

most cases of brachial plexus palsy resolve spontaneously. Infants without signs of recovery at 1 month of age should be referred to a plastic surgeon metatarsus adductus with a rigid foot, 'fixed' talipes equinovarus, polydactyly and syndactyly should be referred for orthopaedic opinion

B. Introduction: Anomalies of the musculoskeletal system may be evident as: - the absence of a part - extra parts - malformed - malfunctioning tissue Anomalies may be congenital or acquired (eg birth trauma) and usually affect the infant's movement, muscle tone, or posture.

C. Upper Extremities: Brachial palsy: is seen most often in large babies who are vulnerable to stretching injuries to the components of the brachial plexus. Erb's palsy and total plexus palsy are the two most common types of injury. Erb's palsy: involving C5, C6 and sometimes C7 causes the affected arm to be adducted and internally rotated, with extension at the elbow, pronation of the forearm, and flexion of the wrist ('waiter's tip' position). Paralysis of the upper arm is more common than paralysis of the lower arm or of the entire arm. The grasp reflex remains intact, but the Moro reflex is absent on the affected side. Complete brachial plexus palsy: presents with a limp, dangling appendage, without any trace of movement. Klumpke's palsy: involving C7-8 and T1, is purely a lower brachial plexus palsy that presents as a clawed hand with function at the shoulder and elbow. There is also an associated dilation of the pupil on the side of the injury (the nerves which dilate the pupil leave the spinal cord on the C8 and T1 nerves and then travel with the artery to the brain and eye).

33

Management of Brachial Plexus Palsy: - X-ray of the clavicle and upper arm on the affected side, and a chest X-ray to exclude ipsilateral diaphragmatic paralysis - where the nerve roots are not disrupted, most resolve spontaneously with physiotherapy as the only modality of treatment - babies without evidence of recovery by 1 month should be referred to the Erb's palsy and Brachial Plexus Injury Clinic at The Royal Children's Hospital (9345 5391). With the advent of new reconstructive techniques, useful function can be obtained by children who have failed conservative therapy, provided that timely treatment is given

D. Lower Extremities: 1. Developmental dysplasia of the Hip (DDH): Metatarsus Adductus: The most common congenital foot anomaly, metatarsus adductus is caused by intrauterine positioning. It may be a positional (flexible) deformity with no bony abnormality involved or a structural deformity. In a structural deformity, the forefoot usually cannot be abducted beyond the midline (neutral position) and the heel (hindfoot) is in a valgus position. In a positional deformity, the forefoot is very mobile and can be easily abducted. A positional deformity will correct without treatment. In a rigid foot, an orthopaedic consultation is necessary for early treatment. Clubfoot ( Talipes Equinovarus): Clubfoot is one of the most common congenital anomalies with an incidence of approximately 1 per 1000 live births. In Caucasians, males are affected twice as often as females. The involvement is bilateral in 50% of cases. A thorough examination should be made for other anomalies, especially the effects of fetal hypokinesia There are variations in the severity of clubfoot. Some are relatively flexible and correctable with serial exercises and casting. Treatment of fixed deformities can often be started in the nursery; an orthopaedic consultation should be initiated as soon as possible after birth. Syndactyly: This is frequently a familial tendency. The severity varies from minimal 'bridging' between adjacent fingers/toes to complete webbing of the hand/foot. Syndactyly of the toes does not interfere with function but may be unacceptable cosmetically. Treatment for syndactyly of the fingers depends on the severity and the presence of bony abnormalities. An early orthopaedic consultation is needed. Polydactyly: Extra digits are common abnormalities affecting both the hands and the feet, with a familial tendency. The most common type is a floppy digit or skin tag on the lateral side of the hand. It may involve the duplication of a normal looking digit. All digital remnants should be surgically removed.

E. References: • • • •

Tappero EP. 1996. Musculoskeletal system assessment. In Physical Assessment of the newborn, 2nd ed., Tappero EP, and Honeyfield ME, eds. Petaluma, California: NICU Ink, 117-136. Rennie JM, Roberton NRC, eds. 1999. Textbook of Neonatology , 3rd ed., Edinburgh: Churchill, 275-280. Shenaq et al. 1998. Brachial plexus birth injuries and current management. Clinics in Plastic Surgery;25(4):527-535 Committee on Quality Improvement, Subcommittee on Developmental Dysplasia of the Hip. 2000. Clinical practice guideline: early detection of developmental dysplasia of the hip. Pediatrics;105(4 Pt1):896-905.

Further Reading: • •

Ponseti IV, 1996. Congenital clubfoot. Fundamentals of treatment. Oxford University Press, Oxford, New York. Levene M, Tudehope D. 1993. Essentials of neonatal medicine. 2nd ed., Oxford: Blackwell, 315-324.

Web Links: http://www.ubpn.org The home page of the United Brachial Plexus Network. Very interesting

34

13. CONGENITAL ADRENAL HYPERPLASIA A. B. C. D. E. F.

Summary Introduction Diagnosis Investigation Management Reference

A. Summary: - a paediatric endocrinologist should be involved in all cases - families will need referral to endocrinologist/geneticist for appropriate counselling - affected children usually remain metabolically stable for the first two weeks of life - adrenal crises (usually heralded by vomiting and failure to thrive) are often sudden and life threatening - salt replacement, in addition to both glucocorticoid and mineralocorticoid replacement is usually required in the first months of life

B. Introduction: Congenital adrenal hyperplasia (CAH) is an autosomal recessive condition with an incidence of approximately 1 in 12,500 births. Approximately 95% of cases are due to a deficiency of the enzyme 21-hydroxylase which catalyzes the conversion of progesterone and 17-hydroxyprogesterone (17OHP) to deoxycorticosterone and 11-deoxycortisol respectively. This section will focus upon this most common form of CAH.

C. Diagnosis: In the neonatal period CAH may present in one of four ways - a virilised female neonate The clue that neonates with ambiguous genitalia may have CAH is the presence of pigmentation of the areolae and genital skin. There may also be: • other affected siblings • a history of parental consanguinity • significant metabolic derangement: ƒ hyperkalaemia ƒ hyponatraemia ƒ metabolic acidosis ƒ hypoglycaemia (rarely) Related symptoms (vomiting, failure to thrive, haemodynamic collapse) do not usually occur until the second to fourth week of life. Hence it is unusual for affected females to present in critical condition, having most commonly been diagnosed in the first few days of life. Milder degrees of CAH may present in more subtle ways (isolated clitoromegaly, virilisation in early childhood etc) and are usually not associated with metabolic compromise in the neonatal period. Until the diagnosis of CAH is established such neonates should be managed as for the neonate with ambiguous genitalia. - a male neonate with metabolic and haemodynamic collapse, aged 2-4 weeks Presentation can vary from mild (failure to thrive) to catastrophic (sudden infant death). Frequently, presenting males are assumed to have sepsis. The major clinical clues to CAH are the presence of pigmented genitalia and nature of the electrolyte disturbance. - an antenatally diagnosed case of CAH (due to a previously affected sibling) The mother will usually have received pre-natal dexamethasone therapy if the fetus is 46XX. If the antenatal treatment has been successful, affected female neonates should not be virilised, however this is not always the case. - detection in unambiguous and metabolically stable males from newborn screening programs

D. Investigation: -

-

the diagnosis is usually made after an elevated serum 17OHP levels is found. This metabolite is normally elevated in the fetus during the last trimester and in the immediate postpartum period. Therefore results can be difficult to interpret in premature infants and term infants less than three days of age. Ideally assessment of 17OHP levels should be deferred until after day 3 of age where it is available, a confirmatory urinary steroid profile is extremely useful elevation in adrenal androgens and ACTH levels may also be helpful, but are usually not measured if the electrolyte pattern and 17OHP levels are concordant

35

E. Management: -

if the patient is haemodynamically compromised, resuscitation with intravenous normal saline and hydrocortisone is required hypoglycaemia may need correction with intravenous dextrose but care should be taken with the water load exacerbating hyponatraemia once stabilized, oral hydrocortisone (10-15 mg/m2/day, given tds) and fludrocortisone (0.15 mg/ m2/day, given bd) therapy should be instituted. Additional salt (0.5-1.0 gm/10 kg/day) replacement is usually required although there is some variance in opinion regarding this

Tablets should be ground up between two teaspoons and mixed with a few drops of milk. This solution should be transferred to a small, plastic feeding spoon and deposited on the back of the tongue immediately prior to feeds. Hydrocortisone solutions/suspensions should be avoided, as they are notoriously unstable and inconstant in dose delivery.

F. Reference: •

Merke DP, Bornstein SR, Avila NA, Chrousos GP. Future Directions in the Study and Management of Congenital Adrenal Hyperplasia due to 21-Hydroxylase Deficiency. Ann Intern Med 2002 Feb 19; 136(4):320-34

14. CONGENITAL DIAPHRAGMATIC HERNIA A. B. C. D.

Summary Introduction Principles of Prenatal Care Guidelines For Neonatal Care

A. Summary: -

if unexpected delivery occurs in a Level II nursery, resuscitation must be undertaken and supervised by the most experienced clinician available ventilation using a bag and mask should be minimised the baby with a best preductal pO2 <70 mmHg, or a persistent respiratory or metabolic acidosis despite 36 hours of expert effort to optimise ventilatory and circulatory support has a poor prognosis

B. Introduction: Congenital diaphragmatic hernia is a serious congenital abnormality associated with: - pulmonary hypoplasia, worse on the ipsilateral side - structural and functional lung immaturity - a reduction in pulmonary arteriolar cross sectional area - muscular hyperplasia of remaining pulmonary arterioles - an association with other major anomalies, chromosomal and non-chromosomal, in up to 20% of cases 15 - 25 cases occur each year in Victoria corresponding to an incidence of approximately 1:3000. In the early 1990's few were prenatally detected. With the virtual universal occurrence of mid trimester ultrasound examination for fetal abnormality more than 85% of cases are now prenatally detected. The survival rate for all cases diagnosed is approximately 50-60%. If a coexistent significant abnormality is present survival is <10%. This illustrates the importance of thorough evaluation, from the time of suspected fetal diagnosis, by a multidisciplinary team familiar with all aspects of the diagnosis and management of CDH.

Reported survival for live born infants ranges from 50-90%. The international CDH Study Group database with over 1600 patients reports an overall survival of 66%. The experience for babies managed at RCH, Melbourne shows the survival for babies with isolated lesions to be 75% based on more than 200 infants. The difference in survival for all cases versus liveborns reflects the high rate of termination of pregnancy (TOP) where other anomalies are detected, a lower rate of TOP where an isolated lesion is present, as well as a relatively low incidence of stillbirth.

C. Principles of Prenatal Care: -

referral for tertiary level obstetric ultrasound if the diagnosis is confirmed referral to a multidisciplinary fetal diagnostic/management team

36

1. Objectives:

-

-

establish an accurate description of the abnormalities present specify ultrasound features relevant to CDH using a standard form: • degree of mediastinal shift • liver/stomach position • lung:head ratio • liquor volume fetal echocardiogram performed by a Paediatric cardiologist, if associated congenital heart disease suspected establish a fetal karyotype, if informed parental consent given provide informed and supportive counselling for the family including a written summary of any discussion with the parents. This summary should include a description of the abnormalities and most likely diagnoses, management options available, and possible outcomes

2. Ongoing Management:

-

referral to a Paediatric Thoracic Surgeon if not previously arranged regular general obstetric surveillance repeat Ultrasounds at 24, 30 and 34 weeks to assess fetal growth and features of the CDH as defined above

3. Intervention:

-

prenatal steroid therapy - recommended according to usual indications. Clinical trials are under consideration for use at mature gestations fetal operative intervention (tracheal ligation) is an unproven therapy. It is not available in Australia and is not recommended outside of clinical trials (currently in progress overseas)

4. Delivery Strategy:

- to achieve a normal vaginal delivery following spontaneous onset of labour at term Women who live more than 1 hour from the perinatal centre are encouraged to move to Melbourne at 35-36 weeks gestation. For pragmatic reasons induction of labour at 38-39 weeks is offered to these women. Caesarean section without labour is not recommended unless there is a clear medical indication.

D. Guidelines For Neonatal Care: If unexpected delivery occurs in a Level II nursery, resuscitation must be undertaken and supervised by the most experienced clinician available.

1. Resuscitation: Resuscitation will be individualised according to the condition of the baby and the response to initial steps in resuscitation. Ventilation using a bag and mask should be minimised. If endotracheal intubation is required make sure the tube is not inserted too far. Positive pressure ventilation should be accompanied by inspiratory pressure or volume monitoring, when available. IPPV, if required, should be provided by a mechanical ventilator at the earliest opportunity. A large bore nasogastric tube (Ryles tube 10F) should be passed once the baby has been stabilised in the delivery room. Physical contact with the parents should be facilitated before transfer. Preductal saturation monitoring should be undertaken during any transfers. Saturations in the 70's and 80's are satisfactory provided sufficient ventilatory support is provided to ensure adequate tidal volume. This is the most difficult situation to get right and in the absence of portable volume monitors a highly experienced clinician must be supervising this period.

37

2. Stabilisation - immediate priorities:

-

-

achieve acceptable gas exchange: • saturations > 75% • pCO2 at a level that allows the pH to be > 7.20 while minimising the chances of inducing lung injury or air leak. monitor preductal saturations apply a transcutaneous pCO2 monitor consult with NETS and level 3 centre

Units reporting very high survival concentrate on minimising lung injury especially in the initial hours after birth and rarely exceed PIP of 25. If available use a synchronised mode of ventilation

3. Ongoing Stabilisation:

-

-

establish venous access - if the baby's condition is poor and the circulation compromised rapidly place a UV catheter measure blood pressure and assess the circulation to determine the need for volume support obtain a chest X Ray if the baby's condition remains poor obtain a blood gas by the most expedient route (arterial stab) and adjust support accordingly arterial access • if urgent - cannulate the UA • if non urgent then either the procedure can be deferred until the baby has been transferred, or a right radial (i.e. preductal) line sited • do not waste time (and arteries) if the first attempt is unsuccessful sedate and muscle relax the baby who remains in poor condition despite attempts at optimising ventilation. In particular muscle relaxants should be considered if the baby requires high pressure IPPV (e.g. a mean airway pressure of > 14) surfactant administration (survanta, one ampoule) is optional. Some babies with CDH tolerate this procedure very poorly

The baby with a best preductal pO2 <70 mmHg, or a persistent respiratory or metabolic acidosis despite 3-6 hours of attempting to optimise ventilatory and circulatory support has a very poor prognosis.

4. Continuing Management:

-

-

requires a team of neonatologists, paediatric surgeons and paediatric intensivists continuous monitoring of transcutaneous pCO2, tidal and minute volumes the lowest FiO2 that results in a preductal saturation > 85% is maintained, especially in the initial hours of care. Permissive hypercarbia is strongly advocated preductal arterial access is desirable if the infant's condition is marginal assessment for dysmorphism - including echocardiography, renal and cranial sonography, a karyotype should be considered an ongoing metabolic acidosis requiring repeated large doses of base suggests myocardial ischaemia, sepsis or strangulated bowel the principles of management and escalation of therapy include: • use of muscle relaxants and sedatives • synchronised ventilation (SIMV or A/C) with tidal/minute volume monitoring • HFOV +/- Inhaled nitric oxide if the baby has unsatisfactory gas exchange after a reasonable trial of conventional ventilation, or there is an ongoing need for high ventilatory pressures or FiO2 • jet ventilation if there is overt gas trapping or air leak • ECMO - less than 10% of babies need this surgery - after ventilatory and circulatory support weaned to satisfactory levels (e.g. FiO2 < 0.4 and mean airway pressure < 14) discharge to a level II unit considered after • full enteral nutrition established for at least one week • respiratory status indicates significant reserve audiology - arranged prior to discharge if possible long term follow up required

38

15. CONGENITAL INFECTION A. B. C. D. E. F.

Toxoplasmosis Rubella Cytomegalovirus (CMV) infection Herpes Simplex Virus (HSV) Syphilis Further reading

Introduction: There are a number of organisms that can cause congenital neonatal illness - often with devestating long term consequences. Rubella embryopathy was the first documented neonatal congenital infection, being recognised in 1941 by an Australian Ophthalmologist - Sir Norman Grigg. Congenital infection can occur during pregnancy or the peri-partum period. Primary infection in the mother, generally, results in greater risk of consequences to the developing fetus compared with 're-activation'. The timing of infection is important in regards to the severity of neonatal illness and in relation to the organism involved.

A. TOXOPLASMOSIS: 1. 2. 3. 4. 5. 6. 7.

Summary Introduction Clinical features Investigation Management Outcome Prevention

1. Summary:

-

Congenital Toxoplasmosis occurs in between 0.2 to 10 per thousand pregnancies Risk of fetal infection is lowest in early pregnancy but most fetuses infected early have severe consequences Specific therapy is available to treat congenital toxoplasmosis

2. Introduction: Toxoplasma gondii is a parasitic organism. The domestic cat is the primary host. Infection can be contracted by: - ingesting oocytes present in faecal material of infected hosts - eating pseudocysts present in undercooked meat. Most women have no symptoms. Although 15% of women report acute flu-like illness with lymphadenopathy. Risk of fetal infection is lowest in early pregnancy but most fetuses infected early have severe consequences.

Risk of fetal infection

Severe consequences of infection

1st trimester

10%

70%

3rd trimester

60%

<1%

3. Clinical features: Infants congenitally infected with Toxoplasmosis can be: - completely asymptomatic - unaffected at birth and manifest problems later - severely affected in-utero and at birth Infection usually affects the neurological and haemopoietic systems. The classical tetrad described by Sabin in 1942 includes: - hydrocephalus/microcephaly - chorioretinitis - convulsions (link) - other evidence of CNS involvement (including calcification) Haemopoietic manifestations include: - hydrops due to anaemia - rash due to thrombocytopenia purpura - blueberry muffin appearance (seen in 25% of generalised infection) - lymphadenopathy

39

- hepatosplenomegaly Neurological manifestations include: - convulsions - hydrocephalus with bulging fontanelle - microcephaly - chorioretinitis can be present early or develop later Generalised features include: - lethargy and malaise - poor feeding - vomiting - diarrhoea - temperature instability - jaundice 4. Investigation: Antenatal diagnosis can be performed using fetal blood sent for: - PCR - IgM assay - culture Postnatal investigations include; - specific IgM or IgA in cord or baby's blood - FBE (anaemia/thrombocytopenia) - liver function tests - culture by inoculation of blood/placenta in mice - cranial US (hydrocephalus and calcification) - CT scan (more sensitive than ultrasound at identifying calcification) - ophthalmological review

5. Management: Treatment consists of prolonged therapy for the first year of life with: - pyrimethamine (1mg/kg orally daily) - sulphadiazine (50mg/kg orally, twice daily) - folinic acid (1ml/kg, orally twice weekly) is added Bone marrow suppression and hepatotoxicity can develop, and fortnightly blood tests are needed. An alternative regime aimed at minimising toxicity may be used: - 4 x 21 day cycles of pyrimethamine, sulphadiazine and folinic acid - spiramycin (50mg/kg, orally twice daily) used for 30 days in between The addition of steroids in severe infection has been suggested, but no evidence exists for this practice. Ongoing opthalmological and developmental follow up is mandatory.

6. Outcome: Infants symptomatic at birth have high incidence of long term difficulties: - chorioretinitis (over 90%) - developmental delay (50%) - seizures (40%) - microcephaly (20%) - deafness - hydrocephalus Outcome data for infants who are asymptomatic at birth is scant. In 'asymptomatic' neonates, it appears that a significant number develop long-term sequelae if left untreated. Up to 92% develop long-term problems, usually due to ophthalmological disease. Chorioretinitis may not become evident for many years. Although prolonged therapy reduces the incidence of sequelae compared to untreated infants sequelae may still occur (over 80%).

7. Prevention: Prevention of Toxoplasmosis is aimed at preventing ingestion of infected material. Pregnant women should be warned to avoid foods/products that may be contaminated with the oocytes - including care with the family cat (there may be a role for advocating against acquiring a new cat in households with pregnant women).

40

B. RUBELLA: 1. 2. 3. 4. 5. 6.

Introduction Clinical features Investigations Management Prevention Outcome

1. Introduction: Most people develop immunity (if not immunised) during childhood. In non-immunised populations, 10-20% of women of child bearing age are susceptible. Re-infection occurs in around 2% of people but is generally subclinical. Cases of congenital infection have been described with maternal re-infection. Rubella vaccination is effective in almost totally eliminating congenital rubella infection - provided coverage remains high.

2. Clinical features: Most congenital infection is the result of primary maternal infection. The mother may have had little, if any, symptoms of infection.

Onset of maternal infection <12 weeks 12-18 weeks >18 weeks

Fetal Complications Congenital rubella syndrome (>90%) Sensorineural deafness (20%) Rare

Congenital rubella syndrome is a severe, disabling condition featuring:

-

-

eye disorders (cloudy cornea/cataracts, salt and pepper chorioretinitis, microphthalmia) sensorineural deafness cardiovascular (pulmonary stenosis and PDA) microcephaly growth restriction haemopoietic disorders: • hepatosplenomegaly • lymphadenopathy • thrombocytopenia • anaemia • extramedullary heamopoiesis (blueberry muffin skin appearance) long bones radiolucencies seen on Xray pneumonitis with associated respiratory signs renal tract abnromalities

3. Investigations: Diagnosis is usually demonstrated by evidence of maternal seroconversion or rising IgG titres. This occurs some 10 days after contact. IgM assay is useful where exact 'contact time' is not known. IgM persists for around 2 months after primary infection. Re-infection can be identified by seeing a four-fold or more rise in IgG titres. Fetal diagnosis is possible from: - cord blood IgM - rubella PCR of amniotic fluid Postnatal diagnosis is by: - IgM - isolation of rubella virus (possible form many sites including NPA, eye, throat, CSF, stool and urine for up to 12 months) Other test include: - FBE - renal function and electrolytes - liver function tests

41

-

cranial ultrasound (looking for discrete calcification) echocardiography (looking particularly for Pulmonary Stenosis and PDA) renal ultrasound LP (pleocytosis with elevated protein) CXR (indicated if the baby has respiratory symptoms) long Bone Xrays hearing assessment is mandatory, even in babies with no overt disease at birth.

Deafness may be progressive, and therefore serial hearing assessments over the 1st few years of life are essential. Ophthalmological assessment is also essential and progressive retinal damage can be seen. Endocrine problems can occur in the long term including diabetes mellitus and hypothyroidism .

4. Management: There is no specific treatment. Management is supportive and aimed at addressing specific problems present (developmental/sensory/endocrine/cardiac/etc ).

5. Prevention: Rubella immunisation is offered to all children in combination with measles and mumps vaccination at 1 year of age. This also reduces the 'viral pool' in the population and helps protect susceptible pregnant women. New arrivals into Australia also are a potential group of susceptible individuals. All women should be screened at first antenatal clinic appointment, and if found to be rubella susceptible, offered immunisation in the post-partum period. If rubella infection is confirmed in the pregnant woman, then appropriate counselling is essential to provide the woman with information regarding the likely effects on the unborn child and options for management.

6. Outcome: Children with congenital rubella syndrome are likely to have severe developmental issues. Ongoing hearing and vision assessments are essential in babies whose mothers contracted rubella after 12 weeks gestation. Rarely, a form of subacute sclerosing panencephalitis, with demonstration of raised rubella antibodies in CSF, has been documented.

C. CYTOMEGALOVIRUS (CMV) INFECTION: 1. 2. 3. 4. 5.

Introduction Clinical features Investigations Management Prevention

1. Introduction: CMV is a ubiquitous herpes virus that usually it causes only mild disease. It is commonly acquired in infancy and childhood through 'saliva sharing', particularly in less developed countries where over 90% are infected in childhood compared to around 60% in Western countries.

2. Clinical features: Overall, around 5 to 10 per 1000 babies are born with congenital CMV infection - with only 5-10% being symptomatic. Congenital CMV can develop from maternal primary infection or re-activation, with primary infection more likely to result in sequelae. Risk for sequelae is highest after fetal infection during the first trimester. Around 1% of non-immune women develop primary CMV in pregnancy, approximately 50% of their fetuses become infected. In women with prior CMV infection, re-activation can occur in pregnancy with 5% of babies developing infection inutero. Perinatal and postnatal infection can occur through birth canal secretions and breast milk or blood. If affected the clinical syndrome is usually mild and self-limiting. Severe infection can result in transfusion-acquired disease. Use of CMV negative donor blood or deglycerolised frozen blood transfused through a leucocyte filter prevents this problem.

42

Symptomatic babies can be variously affected including: - growth restriction - haemotological problems: • thrombocytopenia and purpura are common • anaemia, neutropenia, lymphocytosis are occasional • hepatosplenomegaly • lymphandenopathy - neurological problems: • poor tone and poor suck • seizures • microcephaly • chorio-retinitis • cerebral calcification (classically periventricular) • deafness (can be a late manifestation and is the most common cause of sensori-neural hearing loss) - pneumonitis - colitis - hepatitis - dental defects

3. Investigations: A high index of suspicion is needed. Investigation is warranted in: - babies whose mothers have developed primary infection in pregnancy or have 're-activated' - growth restricted infants with low platelet count Tests performed include: - IgM assayed from cord/baby blood ( tests have poor sensitivity) - viral culture from urine (the test of choice) - throat/saliva swab and NPA sent for PCR can give a more rapid answer. Culture and PCR should be performed as soon as possible in the first 2 weeks of life as CMV detected after this time can indicate peri/post natal infection.

4. Management: Attention to 'general' measures include management of: - nutrition - haemotological disturbances (low platelets) - respiratory disease Specific treatment with foscarnet of ganciclovir has not been shown to be associated with long-term benefits in congenital infection. There is a role for their use in life-threatening CMV infection (particularly post-natal disease in preterm babies) or in the setting of chorio-retinitis but this will not reverse damage that has already been done. Long-term follow-up is essential with attention to: - management of neurological sequelae - hearing testing, continued for the first 2 to 5 years of life, due to the risk of late-onset deafness

5. Prevention: Two groups require consideration: - hospitalised newborn infants: • prevention of transfusion acquired infection is achieved by use of leucocyte filters or CMV negative blood • standard precautions and aseptic measures (particularly hand-washing, especially after nappy changing) is important to prevent nosocomial spread of infection - potentially 'at-risk' pregnant women After infection viral shedding can either persist for months or occur transiently and then recur intermittently. Testing for viral shedding will not guarantee a baby is not shedding virus at other times. Seronegative staff members have a low risk (around 1-5%) of developing a primary infection. Attention to prevention through use of standard precautions is important. Likewise, it is difficult to advise parents of babies with documented CMV infection as to what to tell friends/family. Re-assurance and explanation about prevention of spread through scrupulous attention to hand washing after performing baby care are the most valuable tools.

43

D. HERPES SIMPLEX VIRUS (HSV): 1. 2. 3. 4. 5. 6.

Introduction Clinical features Investigations Management Prognosis Prevention

1. Introduction: HSV 1 and HSV 2 are uncommon, but important, causes of neonatal illness. Neonatal infection is usually the result of HSV 2 as this is the main virus associated with genital infection. The overall rate of genital HSV infection varies from country to country and many women (amd men) remain asymptomatic, with no history of infection despite shedding virus. HSV can remain latent for long periods, with shedding or re-activation occurring at any time. There is a 1% chance of a women with a past history of genital HSV infection shedding virus at the time of delivery. In cases of neonatal infection, most women do not give a history of active genital herpes at the time of delivery. Babies born to mothers with a primary genital infection at the time of delivery have a 50% risk of developing infection, compared with <5% in cases of recurrent infection present at the time of delivery.

2. Clinical features: Neonatal HSV usually presents within 2 weeks of birth Infection occurs in less than 5 per 100,000 deliveries (up to 10 times more in the USA). - 90% are acquired during passage through the birth canal or through ascending infection - 5% have 'congenital' HSV infection - 5% have post-natally acquired infection Usual clinical presentations are: - skin/eye/mouth (SEM) localised disease: • untreated, >70% will progress to disseminated disease • 25% will have virus in CSF at initial presentation • isolated vesicles or 'crops • occassionally other skin reactions can be present, including zoster-like eruptions • keratoconjuncitivitis with dendritic ulcers • choriodoretinitis • single of multiple oral vesicular lesions can be present - disseminated disease: • poor prognosis, with over 70%mortality untreated • non-specific presentation with: ƒ lethargy ƒ poor feeding ƒ fever ƒ convulsion ƒ apnoea ƒ respiratory distress ƒ hepatomegaly ƒ jaundice ƒ DIC - Pneumonitis: • tends to occur day 4 to 7 • respiratory distress and can develop into haemorrhagic pneumonitis • CXR shows diffuse pnuemonic change • rare but dissemination is common if untreated - meningo-encephalitis: • isolated or part of dissemnated disease • presents with: ƒ encephalopathy (mean 11 days of age) ƒ seizures are common and often intractable ƒ absent gag-reflex is a particular feature - EEG shows characteristic temporal/parieto-temporal focus with periodic slow and fast waves. - brain imaging (CT/MRI) shows disease particularly affecting the temporal areas. Later calcification and cerebral atrophy can develop.

44

3. Investigations: Neonatal HSV infection is uncommon and a high level of vigilance is needed, particularly since most affected newborns are born to mothers with no history of current genital HSV lesions. The unwell baby should be examined for vesicles including oral. Specimens from lesions, throat and eye swabs should be performed. The use of immunoflourescence can provide rapid evidence of infection. Viral culture can take 5 days to demonstrate typical cytopathic changes. Lumbar puncture is mandatory, with CSF sent for PCR and culture. However, negative PCR testing on CSF does not completely rule out HSV infection, and the clinical picture of herpes encephalopathy is important in determining treatment. EEG and brain imaging are useful adjuncts in cases where diagnosis of CNS infection is in doubt. Serological studies are of little value early on as IgM may take 2 weeks to appear and IgG titres may not rise in babies and may reflect maternal antibody status.

4. Management: Specific early treatment is with: - Acyclovir 10mg/kg IV three times daily for a total of 14 to 21 days - Vidarabine 15mg/kg 12 hourly, IV is also effective but is more cumbersome Supportive care as always is vitally important with attention to general care. Eye lesions require topical treatment (eg. Idoxuridine) and ophthalmological referral is essential.

5. Prognosis: Mortality and morbidity rates for disseminated and CNS disease are very high, even with early and aggressive treatment. Even in the setting of localised SEM disease, 10% have long-term neurological sequelae. Recurrent skin and eye eruptions can occur. Oral acyclovir has a role in this setting.

6. Prevention: Babies born to mothers with active genital herpes lesions, particulary primary infection, at the time of delivery are at high risk. LUSCS should be performed as soon as possible, particularly within 6 hours of ROM. Swabs from the baby's eyes and throat should be sent and if positive, the baby treated with acyclovir sysemtically. However, consideration to treatment even in the setting of CS should be given - especially if there delay in getting results occurs. Babies born vaginally in the face of active genital lesions should be treated systemically. Nosocomial infection can occur and vigorous infection control measures should be instituted. Relatives or staff with 'cold-sores' should be discouraged from handling newborn infants as there is a risk of infection. Mothers with cold-sores present a low-risk to the infant as passive antibody protection of the baby should be present, but in this setting the wearing of masks/rigorous handwashing and topical cold-sore treatment should be advocated.

E. SYPHILIS: 1. 2. 3. 4. 5. 6.

Introduction Clinical features Investigations Management Follow-up Prevention

1. Introduction: Congenital syphilis is rare in Australia, disadvantaged groups are at higher risk. Screening at the initial antenatal visit is part of routine obstetric care since women may have asymptomatic latent disease. Untreated maternal syphilis can result in: - stillbirth/perinatal death - premature delivery - about half of survivors have long-term neurological sequelae. Transmission rates are around 50% for primary, secondary or early latent syphilis. In established latent syphilis, vertical transmission occurs in around 10%. Treponema pallidum infection remains treatable with penicillin.

45

2. Clinical features: The infected baby can: - be asymptomatic at birth - have disseminated sepsis with: • reticulo-endothelial/haemotogical features: ƒ generalised lymphadenopathy and hepatosplenomegaly seen in over 50% ƒ haemolytic anaemia/thrombocytopenia/pancytopenia can occur ƒ occassional leucocytosis ƒ jaundice (unconjugated/conjugated or mixed) is common • mucosal features: ƒ rhinitis (snuffles) develops at 1 week and worsens. Initially clear then progressively purulent and blood stained ƒ mucous 'patches' seen on palate and lips ƒ perioral and perianal condylomata ƒ ulceration of nasal mucosa can lead to 'saddle-nose deformity' in longer term • cutaneous features: ƒ maculo-papular eruption over buttocks and lower torso, palms and soles ƒ bullous eruptions (pemphigus syphiliticus) which mimic staphyloccal infection ƒ desquamation • bone involvement: ƒ osteo-chondritis, periostitis, osteitis is very common (>75% of cases). Usually asypmtomatic initially but can lead to deformity and pathological fracture • neurosyphilis (rare at birth): ƒ meningitis ƒ eye involvement: ƒ gluacoma ƒ chorioretinitis ƒ chancres ƒ uveitis • myocarditis • pneumonitis • renal (nephrotic) involvement • if untreated, late features include: ƒ Hutchison's teeth and other dental deformity ƒ Sabre tibia ƒ keratitis and blindness ƒ nerve deafness ƒ saddle nose deformity ƒ frontal skull bossing ƒ scarring ƒ development impairment

3. Investigations: Pregnant women are screened with non-specific treponemal tests (RPR and VDRL titre). If positive, then a specific TPHA/FTA-Abs titre will be performed. Serum IgM in newborn babies with congenital syphilis is positive in around 90%. Diagnosis of congenital infection can be confirmed by demonstration of treponema pallidum on dark ground microscopy on specimens from lesions on skin, placenta or other tissues. A fourfold rise in the baby's antibody titre over the first 3 months is considered diagnostic. Other tests:

-

FBE liver function tests urinalysis for proteinuria X-rays of long bones lumbar puncture: • CSF abnormalities should be considered suggestive of CNS infection • a positive CSF VDRL titre or treponema PCR is diagnostic of CNS involvement

46

4. Management: Babies born to mothers who have not been adequately treated should be considered as infected. Infants with suspected or confirmed infection should be treated with penicillin for at least 10 days. Benzyl penicillin, 30mg/kg per dose 12 hourly, IM or IV or Procaine penicillin, 30mg/kg daily, IM Infants with low antibody levels whose mother was treated appropriately and has evidence of falling RPR/VDRL titres, is unlikely to be at risk. Ongoing follow up will be needed and if follow up cannot be assured, the baby should be treated.

5. Follow up: Babies should be evaluated at 3-monthly intervals over the first year of life, with serological tests performed at each visit.. In cases of neurosyphilis, ongoing serum and CSF analysis should be undertaken 6-monthly for the first 5 years of life. Re-treatment is needed if titres do not fall, or clincial signs of disease persist or develop.

6. Prevention: Prevention relies upon adequate antenatal services and screening facilities.

F. Further reading: • • • • • • • • • •

Isaacs D, Moxon ER. "Handbook of Neonatal Infections - a practical guide". WB Saunders, London. 1999. Remington JS, Klein JO. "Infectious Diseases of the Fetus and Newborn Infant" 5Th Ed. WB Saunders, Philadelphia. 2000. Davies EG, Elliman DAC, et al. "Manual of Childhood Infections". WB Saunders, London, 1996. Jeffries DG, Hudson CN. "Viral infections in Obstetrics and Gynaecology". Arnold, London, 1999. Jones JL. Lopez A. Wilson M. Schulkin J. Gibbs R. Congenital toxoplasmosis: a review. Obstetrical & Gynecological Survey. 56(5):296-305, 2001 May Beazley DM. Egerman RS. Toxoplasmosis. Seminars in Perinatology. 22(4):332-8, 1998 Aug. Jacobs RF. Neonatal herpes simplex virus infections. Seminars in Perinatology. 22(1):64-71, 1998 Feb. Murph JR. Rubella and syphilis: continuing causes of congenital infection in the 1990s. Seminars in Pediatric Neurology. 1(1):26-35, 1994 Sep. Riley LE. Herpes simplex virus.Seminars in Perinatology. 22(4):284-92, 1998 Aug. Hollier LM. Cox SM. Syphilis. Seminars in Perinatology. 22(4):323-31, 1998 Aug

16. CYANOSED INFANT ASSESSMENT A. B. C. D. E. F. G.

Introduction Differential Diagnosis of a Cyanosed Infant General Approach to the Cyanotic Infant Differential Diagnosis Cardiac Causes Prostaglandin E1 (PG) Infusion Reference

A. Summary: - echocardiography is the gold standard for the assessment of congenital heart disease in infancy - all infants with central cyanosis should be commenced on parental antibiotics early until further -

investigation is possible. differentiating PPHN from ductal dependent pulmonary cardiac lesions can be very difficult; if uncertainty exists a PG infusion is generally the safest option for transport

B. Introduction: Central cyanosis affects 3-4% of all newborns and is a marker of significant disease. The causes are varied including: - primary pulmonary disease - cardiac malformations - persistant pulmonary hypertension - sepsis - anaemia - asphyxia - metabolic conditions - methaemaglobinaemia

47

C. Differential Diagnosis of a Cyanosed Infant: Breathing Pattern

Tachypnoea, grunting and Primary Pulmonary recession Disease Cardiac

Tachypnoea, slow/deep breathing

PPHN

Tachypnoea, recession and grunting may be present

Sepsis

Respiratory distress may be present

Right & Left SaO2 difference

pCO2

no

No difference

+/(usually 5-10%) >10 - 15% No difference

Severe Response to Metabolic 100% O2 Acidosis

Normal or Normal or Normal or

PaO2 and SaO2

Present

No significant change

+/-

+/-

+/-

Moderate PaO2 or SaO2

(PPHN = Persistent Pulmonary Hypertension of the Newborn) History and presentation may allow the cause to be easily identified but often differentiating cause is difficult without echocardiography, especially in infants with relatively little respiratory distress. Transporting infants with severe cyanosis is difficult whatever the aetiology and stabilisation prior to transport is particularly important. Fortunately with adequate stabilisation, the overall transport-related mortality in infants with suspected cardiac disease is 0.7%. Echocardiography is the gold standard for the assessment of congenital heart disease in infancy.

D. General Approach to the Cyanotic Infant: - Confirm central cyanosis with arterial blood gas (ABG) in room air, if possible, a sample from the right arm -

-

-

is the best site Assess the history and examination for cause, including four limb BP: • an upper to lower limb systolic difference of > 10mmHg is significant and suggestive of Coarctation of the Aorta • hypotension in a cyanotic infant is a serious finding Correct metabolic acidosis and systemic hypoperfusion if present with fluid boluses and bicarbonate Hyperoxia Test (HT): • 100% FiO2 into headbox for > 10 min • monitor SaO2 • Repeat ABG: ƒ PaO2 > 100mmHg or SaO2 increase by 15%: pulmonary disease likely ƒ PaO2 < 70mmHg, rise by < 30mmHg or SaO2 unchanged: cardiac cause or PPHN likely ƒ Total Anomalous Pulmonary Venous Drainage (TAPVD) and Hypoplastic Left Heart syndrome may respond ƒ Pulmonary disease with a massive intrapulmonary shunt may not respond • Limitations of HT: ƒ HT is not as reliable as an echocardiogram and is not as important as resuscitation and attendance to cardiorespiratory support, especially if acidosis or respiratory distress is present ƒ HT has many limitations especially when only saturations are measured and not arterial PaO2 and should only be used in conjunction with a thorough clinical assessment Assess right and left sided SaO2 for any ductal difference CXR and ECG if possible Intubation and paralysis if significant distress Two IV lines ideally or UVC Parental antibiotics (preferably after blood cultures taken) Prostaglandin E1 infusion if duct dependent cardiac disease is suspected Consider inotrope support to maintain BP/improve cardiac contractility Infants should be transferred to a centre with Paediatric Cardiology and Cardiac Surgery facilities readily available

48

E. Differential Diagnosis: - Sepsis: Sepsis with a low output state may cause: • poor pulses • severe metabolic acidosis • blunted response to HT • absent respiratory distress (if no primary lung pathology) Differentiating the infant in severe septic shock from other causes of cyanosis is very difficult and no safe clinical measures exist. Thus, generally all infants with central cyanosis should be commenced on parental antibiotics early until further investigation is possible.

-

PersistantPulmonary Hypertension Of The Newborn (PPHN):

PPHN results from an altered pulmonary vasoreactivity and raised pulmonary vascular resistance, this causes a right to left ductal shunt. Most infants present with respiratory distress and cyanosis. Usually the infant is tachypnoeic, shows labile oxygenation and has evidence of right ventricular strain (prominent right ventricle impulse and tricuspid regurgitation murmur). There is usually a pre- and post-ductal difference of 10-15% in SaO2 and 10-15mmHg PaO2. Despite this a degree of clinical variability exists depending on the severity, stage of disease and underlying pathology. If PPHN is suspected hyperventilation for 10 minutes is a useful clinical test when other investigative options are unavailable. Infants with PPHN show improved oxygenation (PaO2 increasing by >30mmHg) when pH is raised to 7.55. Prolonged hyperventilation is not recommended due to the cerebral effects of prolonged hypocapnia. Differentiating PPHN from ductal dependent pulmonary cardiac lesions can be very difficult; if uncertainty exists a PG infusion is generally the safest option for transport and infants with PPHN may show some improvement on infusions of 50-60 nanog/kg/min.

F. Cardiac Causes: Generally an infant with cyanosis and a murmur has a high probability of a cardiac cause, absence of pulses further raises the probability. Infants presenting with cyanosis due to a cardiac cause have a high probability of a ductal dependent lesion involving either: - Ductal Dependent Pulmonary Circulation presenting with: • cyanosis • tachypnoea without respiratory distress • adequate perfusion initially • such as: ƒ critical pulmonary stenosis ƒ transposition of the great vessels - Ductal Dependent Systemic Circulation (critically obstructed systemic circulation) presenting as: • cardiac failure with systemic hypoperfusionhypoperfusion • poor or absent peripheral pulses • increasing metabolic acidosis • cyanosis may not develop until the latter stages of the clinical course • Such as: ƒ coarctation of the aorta ƒ hypoplastic left heart syndrome ƒ critical aortic stenosis - Management: Aim to maintain adequate tissue perfusion and ductal patency rather than correcting the cyanosis. • minimise pulmonary blood flow: ƒ moderate PEEP (4-6 cm H20) ƒ ventilate in air if possible ƒ aim for a CO2 of 37 - 45 mmHg ƒ SaO2 75 - 85% • maximise tissue perfusion: ƒ fluid resuscitation (saline 10ml/kg boluses) ƒ low dose inotropes (dopamine/dobutamine) - further details in section on management of shock ƒ sodium bicarbonate if BE > -10 (dose (mmol) = BE *wt/4) ƒ consider paralysis if infant distressed • achieve ductal patency with Prostaglandin E1

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G. Prostaglandin E1 (PG) Infusion: - When to give? In a cyanotic infant in whom cardiac disease is suspected a low threshold for starting PG is needed. Even in a stable infant the risk of withholding PG is usually greater than the risks associated with PG due to the risk of rapid clinical deterioration when the duct closes, especially in a transport environment. There is evidence that infants with suspected duct dependent cardiac lesions transported with prostaglandin have better outcomes than those in which prostaglandin is withheld and the overall risk to the infant is low. There are no true contraindications to PG but infants with TAVPD may worsen on PG. If the diagnosis is uncertain a trial of PG for 30 to 60 minutes with repeat abg may be warranted and will usually outweigh the risks of delaying treatment.

-

Dose:

When the duct is still open the priority is to prevent further loss of patency, usually a starting dose of 10 ncg/kg/min infusion in 5% dextrose or Normal Saline is adequate. If no improvement in SaO2 then increase dose by 10 nanogram/kg/min increments up to 50 nanogram/kg/min until SaO2 improves. Prostaglandin can be given via a peripheral line, UVC or UAC. Infants in extremis will usually have a closed duct and a higher starting dose of 100 ncg/kg/min will be required to reopen the duct, when saturations improve then dose can be decreased to a dose to maintain ductal patency.

-

Side Effects:

Most frequent side effects include: • fever 12% • apnoea 12% • flushing 10% • hypotension Apnoea will rarely occur at 10 ncg/kg/min and apnoea is not an indication to decrease the dose if the infant is responding clinically, rather respiratory support is warranted. The likelihood of apnoea is very high at a dose of 100 ncg/kg/min and most infants on this dose should have ventilatory support. Close observation is mandatory following commencement of PG infusion, and assisted ventilation and volume expansion or inotrope infusion are frquently required.

-

Who to intubate?

The threshold to intubate an infant on a PG infusion will be lower in a transport or remote setting. Factors to consider include • presence of apnoea • the distance to the receiving hospital • gestation of the infant • clinical state of the infant (metabolic acidosis, shock, severe distress and tachypnoea) • high PG dose required to achieve ductal patency Thus in a stable infant with a PG responsive ductal lesion transport without intubation maybe appropriate. Conversely, it would generally be appropriate to electively intubate an infant requiring high dose PG (although these infants usually require respiratory support for other reasons).

H. References: • • • • • •

Penny DJ, Shekerdemian LS. Management of the neonate with symptomatic congenital heart disease. Arch Dis Child Fetal Neonatal Ed 2001; 84: F141 - F145. Hellstr?m-Westas L et al. Long-distance transports of newborn infants with congenital heart disease. Pediatr Cardiol 2001; 22: 380-384 Buck ML. Prostaglandin E1 treatment of congenital heart disease: use prior to neonatal transport. DICP Ann Pharmacother 1991; 25: 408 - 9 Barry PW, Ralston C. Adverse events occurring during interhospital transfer of the critically ill. Arch Dis Child 1994; 71: 8-11 Jaimovich DG, Vidyasagar D (Ed). Handbook of pediatric and neonatal transport medicine. Ch 8. 2nd Ed. 2002. Hanley & Belfus. Pp 93 - 125 Myung K Park. Pediatric cardiology for practitioners. 3rd Ed. 1996. Mosby-Year Book (St Louis)

Web Sites: • •

Cyanosis in the newborn: The Cyanotic Newborn Infant (University of Minnesota Neonatology Lecture) http://www.kumc.edu/kumcpeds/cardiology/cardiology.html Prostaglandin: http://www.cs.nsw.gov.au/rpa/neonatal/html/listview.asp?DrugID=36

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17. DEVELOPMENTAL CARE A. B. C. D. E. F.

Summary Introduction Interventions in Developmental Care Principles of developmental care Areas Of Uncertainty In Clincial Practice References

A. Summary: - premature neonates are born before brain maturation is complete - the stressful and abnormal environment of the nursery may contribute to altered brain development - modification of the nursery environment may reduce long term morbidity - light protection should not prevent adequate visualisation of the infant B. Introduction: While advances in biomedical technology and improvements in care have led to a decrease in mortality rates in premature and extremely low birth weight neonates, there has not been a corresponding change in morbidity. Comprehensive long term follow up of these infants has lead to the recognition of new morbidities:

-

including learning and attention deficit disorders language comprehension and speech problems and visual and motor impairments

The focus of neonatal care must now extend beyond simply achieving survival. Tthe challenge now is to optimise infants’ developmental course and long term outcome. Developmental problems resulting from damage to the cerebral cortex may not become evident for some months or even years after birth. Infants "at risk" therefore require long term developmental follow up.

C. Interventions in Developmental Care: The aim of developmental care is to modify the environment of the nursery utilising a broad range of strategies designed to:

-

reduce stress and prevent agitation preserve energy and promote growth enhance recovery facilitate self regulatory capabilities promote C.N.S. organisation

Individualised strategies such as the "Neonatal Individualised Developmental Care and Assessment Program" (NIDCAP) have also been used.

D. Principles of developmental care: - recognise physiological stressors: • •

-

certain sensory and motor stimuli may cause physiological changes such as fluctuations in heart rate and oxygen saturation, and/or apnoea such stimuli include handling, painful procedures, or sudden loud noise

protect from light: • constant bright light in the nursery can interfere with the development of natural diurnal rhythms and have an arousing effect on the C.N.S. • reducing light levels may prevent sensory overload and facilitate rest • cover incubator hoods to reduce exposure to bright overhead lights • dim the lights at night to assist in establishing day/ night patterns

Light protection should not preclude adequate visualisation of the sick or potentially sick infant.

-

protect from noise: • noise (above 80-85decibels) has the potential for damage to the cochlear & hearing loss in adults. The immature cochlear is more sensitive to damage • closing portholes with a "snap", dropping the head of the mattress and tapping or placing bottles on the Plexiglas top of the incubator all have a sound level above 80db • noise may also cause agitation, irritability and crying, which may result in increased intra-cranial pressure and decreased oxygen saturation

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• interventions to reduce noise include: ƒ turn the radio down or off ƒ have a designated "quiet time" daily ƒ avoid banging bin lids ƒ remove bubbling water in oxygen/ventilator tubing ƒ close incubator portholes gently ƒ give 'handover' away from the infant’s bedside ƒ avoid talking loudly, especially across open care beds

-

protect from over-stimulation: • handling can effect physiological stability and cause hypoxaemia, especially in the extremely premature, unstable or ill neonate • provide "time out"/ recovery time when the infant demonstrates avoidance or "stress" behaviour. Signs of stress behaviour include: ƒ colour changes: mottled, dusky, cyanosed ƒ apnoea, bradycardia, desaturation ƒ hiccoughing, sneezing, yawning, gagging, regurgitating feeds ƒ tremors, twitches, frantic activity, arching, frowning, gaze averting ƒ completely flaccid trunk, extremities & face ƒ easy fatiguability (take care as these behaviours may have serious underlying causes) • introduce sensory stimuli slowly: eg one toy or picture in the incubator (too many are overwhelming) and be sensitive to the infant’s response

-

alter patterns of care to allow maximum time for sleep and growth: • clustering of cares/ minimum handling approach • positioning: prone or side lying to enhance flexion, bring the shoulders forward and the hands to the midline • provide boundaries and use rolls/nesting to maintain desired posture, reduce agitation, conserve energy and create a feeling of "security" for the infant • avoid moving an infant who has sought out his own boundaries (eg foot against a porthole door)

-

establish day and night patterns (diurnal rhythm): • dim the lights at night and turn the radio off • remind staff to talk & walk quietly around the nursery • avoid non-emergency interventions during the night: eg. bathing & weighing

-

normalise parent expectations: • promote parent understanding of their infant’s behaviour, including signs and manifestations of stress • provide opportunities for Kangaroo Care, Non-nutritive sucking and other forms of sensory stimuli as the infant matures and is able to maintain physiological homeostasis

E. Areas Of Uncertainty In Clincial Practice: - Does developmental care lead to the hypothesised measurable outcomes of: • • • • •

reduction in incidence and severity of developmental delay improved weight gain decreased length of hospital stay less days of mechanical ventilation less days of oxygen dependence?

A Cochrane review of 31 eligible randomised control trials found evidence of some benefit from developmental interventions, with no major harmful effects reported. However, there were a large number of outcomes for which conflicting effects or no effects were demonstrated.

-

Is developmental care cost effective?

Broad interventions such as reducing light and noise in a nursery are easily implemented, of negligible cost and not harmful; however implementing and maintaining a formal developmental care program (such as NIDCAP) has a significant economic impact. Symington & Pinelli (2001) suggest that further evidence of the efficacy of developmental care is required before a clear direction for practice can be supported.

F. References: •

Als, H., Lawhon, G., Brown, E., Gibes, R., Duffy, F.H., McAnulty, G., & Blickman, J.G. (1986). Individualised behavioural and environmental care for the very low birth weight preterm infant at high risk of Bronchopulmonary Dysplasia: Neonatal Intensive Care Unit and developmental outcome. Pediatrics. 78(6): 1123-1132.

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•

Blackburn, S.T. & VandenBerg, K.A.(1993). Assessment and management of neonatal neurobehavioral development. In: Kenner, C., Brueggemeyer,A. & Gunderson, L.P. (eds). Comprehensive Neonatal Nursing: A Physiological Perspective. Philadelphia: WB Saunders, 1094-1134. • Buehler,D.M., Als, H., Duffy, F.H., McAnulty,G.B. & Liederman, J. (1995). Effectiveness of individualised developmental care for low risk preterm infants: Behavioural and electrophysiologic evidence. Pediatrics. 96(5): 923-932. • Symington, A. & Pinelli, J. ((2001). Developmental care for promoting development and preventing morbidity in preterm infant (Cochrane Review). The Cochrane Library, 2, 2001. Oxford: Update Software. • VandenBerg, K.A. (1995). Behaviourally supportive Care for the Extremely Premature Infant. In: Gunderson, L.P. & Kenner, C. (eds). Care of the 24-25 Week Gestational Age Infant. 2nd Ed. Petaluma: NICU INK, 145-171. Web Links: Developmental Progress Clinic at Emory University

18. DEVELOPMENTAL DYSPLASIA OF THE HIP A. B. C. D. E. F. G.

Screening Algorithm Introduction Absolute Risk of DDH per 1000 births Screening Additional Investigations Areas of Uncertainty in Clinical Practice References

A. Screening Algorithm: - all newborn infants should have the Ortolani and Barlow tests performed by a trained examiner as part of

-

-

-

-

the routine newborn examination Unfortunately, infants who are unwell after delivery, and who require admission to neonatal intensive or special care units, often have this important part of their newborn examination omitted. It must always be documented that the examination has been performed both in the infant's medical record and child health record. infants, in whom the examiner is uncertain of the findings, should be re-examined by a more experienced clinician prior to discharge Inexperienced examiners who are unsure whether what they are feeling is a 'click' or a 'clunk' are advised to enlist expert help. infants in whom either test is positive should be assessed by an orthopaedic surgeon prior to discharge and fitted with a Pavlik harness or Von Rosen splint. There is nothing to be gained by performing X-rays or ultrasonography in these infants. In addition, there is no evidence to support the use of double or triple napkins until definitive treatment is instituted high risk infants in whom examination is normal should have ultrasonography performed within 4-6 weeks of birth High risk infants are those with: • breech presentation • history of DDH in a first degree relative (parent or sibling) • neuromuscular disease since DDH can develop over time, all infants (both high and low risk) with normal newborn examinations should have their hips regularly re-examined during the first year of life

B. Introduction: Developmental dysplasia of the hip (DDH) is the preferred term for the disease previously referred to as congenital dislocation of the hip since it recognises that presentation can follow a normal examination of the hips in the newborn period. DDH refers to a spectrum of disorders of hip instability due either to the femoral head being able to move outside the acetabulum (luxation or dislocation), or abnormally within the acetabulum (subluxation or partial dislocation). Early detection is vital since if DDH is left untreated the hip joint develops abnormally and surgical reduction is required. By contrast, early conservative management with splinting (either a Pavlik harness or a Von Rosen splint) allows the hip joint to develop normally and avoids the need for surgery in most cases. Pathogenic factors for DDH include: - abnormal rotation of the developing hip during the first trimester - neuromuscular disease, especially in the second trimester - abnormal mechanical forces e.g. oligohydramnios, breech presentation (particularly frank breech), in the third trimester - female infants (who are more susceptible to the maternal hormone relaxin) - postnatal mechanical forces associated with swaddling (African infants strapped to their mothers' backs with hips abducted have a very low incidence of DDH)

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C. Absolute Risk of DDH per 1000 births: Male Female Studies using Ortalani and Barlow tests for screening

4.1

19

First degree relative with history of DDH

6.4

32

Infant born after breech presentation

29.0

133

The relative risk for infants with a history of DDH in a first degree relative is 1.7 and when born after breech presentation (all types) is 7.0.

D. Screening: There is no 'gold standard' diagnostic test for DDH. The Ortolani and Barlow tests are widely used for screening: • •

The Ortolani test detects a dislocated hip reducing during the examination. The Barlow test detects a hip dislocating or subluxing during the examination.

A positive Ortolani or Barlow test is one in which a distinctive 'clunk' is felt. 'Clicks' are often felt while performing these tests, are not predictive of DDH, but cause considerable confusion. Readers who wish to learn the tests should: - consult an authoritative text - be shown how to perform both tests by an expert - practice the tests on the 'Baby Hippy' manikin - practice the tests on many infants to perfect their technique

E. Additional Investigations: X-rays are unhelpful in assessment as the femoral head is cartilaginous until six months of age.

F. Areas of Uncertainty in Clinical Practice: Ultrasound examination of the hips has been advocated by some as the most effective method of screening for DDH. Although very sensitive as a screening tool, it has low specificity, is expensive and is highly operator dependent. For this reason, the American Academy of Pediatrics considers it most useful as an adjunct to clinical examination.

G. References: • •

American Academy of Pediatrics. Clinical Practice guidelines: Early detection of developmental dysplasia of the hip. Pediatrics 2000; 105:896-905. Griffin PP, Robertson WW Jr. Orthopedics. In: Avery GB, Fletcher MA, MacDonald MG, editors. Neonatology: Pathophysiology and management of the newborn. Philadelphia: Lippincott, Williams & Wilkins, 1999:1270.

Other Reading/Web links: •

AAP Clinical Practice Guideline: Early Detection of Developmental Dysplasia of the Hip RPA Newborn Care

19. DYSMORPHOLOGY ASSESSMENT OF THE NEWBORN A. B. C. D. E. F. G.

Summary Introduction History Checklist Examination Checklist Investigations - when to do what? Communication Strategies with Parents Reference

A. Summary: - a thorough history and examination is required - ancillary investigations may be useful - chromosome and gene tests may be warranted in certain circumstances - parental communication is important - potentially 'offensive' terms should be avoided 54

B. Introduction: A dysmorphology assessment of a newborn focuses on aspects of history, examination and investigations that may lead to a syndrome diagnosis. This assessment should be carried out in any child with any of the following - congenital abnormality - growth abnormalities - dysmorphic features Below are checklists for history and examination with a dysmorphology focus as well as investigations that the paediatrician should consider as part of a dysmorphology work-up. For many doctors, the discussion of issues relating to syndrome diagnosis and dysmorphism can be difficult, and some suggestions are outlined.

C. History Checklist: - pregnancy history, noting particularly exposure to teratogens, amniotic fluid volume - results of ultrasound and amniocentesis/CVS - fetal movements - maternal illness - delivery history - family history of abnormalities - consanguinity D. Examination Checklist: The following focuses on the examination for dysmorphic features in a baby. A thorough examination of all other systems is vital when considering a syndrome diagnosis. a) Growth: Birth weight, length and head circumference. Assess whether the baby's growth parameters are in proportion as well as the percentiles

b) Ectodermal Features:

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skin - texture and colour, birthmarks, redundancy, defects hair - scalp hair and body hair: colour and distribution. Note position of anterior and posterior scalp hairline

c) Skull:

-

shape, symmetry sutures (over-riding/normal/widely open) fontanelle size and number d) Face: In examining the face, it can be useful to first gain an overall impression of the facial appearance. Sometime, an overall gestalt can be diagnostic (e.g. Down syndrome). If no diagnosis is made, it is then important to divide the face into sections to examine it thoroughly. You may divide the face into the forehead, midface and oral region. It can sometimes help to cover parts of the face with your hand, in order to isolate the section of the face you are assessing. In assessing the face, it is important to view the face from the front and from the lateral view. The depth or height of structures such as the nasal bridge, the position of the mandible relative to the maxilla and the development of the midface are best assessed by the lateral view. - Overall face shape, symmetry, facial muscle movement - Forehead region: • forehead shape - (broad/bitemporal narrowing/tall) • eyes: ƒ palpebral fissure length (short/long) ƒ palpebral fissure slant (up/down) ƒ epicanthic folds - a fold of skin which arcs from below the eye into the upper lid ƒ eye spacing (use a rough guide of 1:1:1 for the ratio of left palpebral fissure length: inner canthal distance: right palpebral fissure length) ƒ palpebral fissure shape ƒ iris colour ƒ pupil shape ƒ retina ƒ globe position (assessed from lateral view: protuberant vs deep set globes) - Midface region: • nose divide the nose into 3 sections from the lateral view from superior to inferior into the nasal root, bridge and tip. ƒ root ƒ bridge (depressed/prominent/broad)

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•

-

ƒ ƒ ƒ

tip columella (the vertical ridge separating the nostrils) nostrils - patency, position (anteverted nostrils often reflect a short nose)

ears:

ƒ ƒ ƒ

ear position should be assessed relative to the face, from the lateral view ear rotation is normally 15 degrees posterior to the vertical plane of the head ear shape and structure

Oral region: • mouth size and shape • lip shape, thickness • gum thickness • philtrum definition and length • jaw position (prognathia/micrognathia) • palate shape • oral cavity - natal teeth/frenulum/tongue size and morphology

e) Hands and Feet:

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overall shape and size of hand and foot digit number digit shape (e.g. clinodactyly) and length webbing between digits palmar, plantar and digit creases nail morphology

f) Joints and Skeleton:

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contractures limb shortening joint range of movement soft tissue webbing across joints (pterygium) sternum length and shape (pectus carinatum/excavatum) shape of thoracic cage spine length, straight/curved neck length, webbing

g) Genitalia and Anus:

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phallus size, morphology development of scrotum and palpation of testes development of labia position of anus relative to genitalia, patency of anus

Examination of other family members (siblings and parents) may be crucial to determining whether any dysmorphic features noted are familial or syndromic.

E. Investigations - when to do what? a) Tests in the syndrome work-up: - renal ultrasound, echocardiogram and cranial ultrasound may be indicated when a syndrome is suspected. In particular, midline abnormalities tend to cluster together, so, for example, an echo may be indicated when there is a cleft palate and dysmorphic features - eye examinations are useful for clues to make a syndrome diagnosis - skeletal radiographs - are indicated when there is disproportionate short stature, or other abnormalities in the skeletal system. X rays may be useful in diagnosing a skeletal dysplasia, which is a disorder caused by a primary abnormality of bone growth/development, or to assist in diagnosing a dysmorphic syndrome which can have skeletal abnormalities associated with it A genetic skeletal survey includes: - AP and lateral X rays of the skull - AP and lateral pelvis and spine (cervical to sacrum) - AP of one arm - AP both hands - AP of one leg and AP of both feet In a neonate, it may be sufficient to obtain a "baby-gram" (X-ray of the baby) and a separate X ray of the hands and feet.

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b) Chromosome, fluorescent in-situ hybridisation (FISH), single gene and biochemical tests: Blood chromosomes are indicated:

-

when there are multiple congenital abnormalities +/- dysmorphic features when there is one congenital abnormality in the presence of dysmorphic features and/ or growth retardation

Chromosome abnormalities are more likely when there are abnormalities of growth, most commonly growth retardation and microcephaly, in association with dysmorphic features and congenital abnormalities. Note that a normal chromosome analysis does not exclude a single gene mutation or a micro deletion syndrome. Also, a normal antenatal chromosome analysis does not completely exclude a chromosome abnormality, as the resolution of chromosome banding may be greater on a postnatal sample than samples from chorion villus sampling or amniocentesis. If a chromosome abnormality is strongly suspected, it is indicated to repeat chromosomes in the postnatal period. A chromosome test takes a minimum of 5 days and the time taken to obtain a result depends on the growth of cells in culture. If an infant has been transfused, there is a small risk that there may be circulating lymphocytes from the blood donor, which may lead to an ambiguous result. Most laboratories recommend delaying a karyotype until one week following a transfusion. FISH for Trisomies 13/18/21 are used to expedite diagnosis when Trisomy of a specific chromosome is suspected. A result is usually available within 48 hours. FISH for submicroscopic deletion syndromes are tests using a probe that detects small chromosome deletions not visible on routine chromosome analysis.

-

22q FISH should be considered in babies with heart defects, particularly those with cleft palate and dysmorphic features. The commonest cardiac defects seen are conotruncal heart defects and VSD 7q FISH (Williams' syndrome) should be considered in babies with supravalvular aortic stenosis and/or hypercalcaemia

Fragile X testing is rarely indicated in the neonatal period in the absence of a family history. Single gene tests may be indicated, depending on the syndrome being considered. Such tests usually require liaison with the clinical geneticist. Biochemical tests may be indicated, such as 7-dehdrocholesterol assays if considering Smith-Lemli-Opitz as a diagnosis.

F. Communication Strategies with Parents: It can be awkward to raise a concern that a child is dysmorphic. However, it is important to communicate concerns to the family in order to assist them in understanding the reasons behind investigations, examinations of other family members, and referrals to genetics. Withholding concerns regarding dysmorphism can be bewildering and frightening to parents. One useful tactic is to ask the parents whom the child resembles in the family. The family may then disclose their concerns regarding the child's appearance, and this can then be a topic for careful discussion. Geneticists often explain that the reason for examining the baby's appearance is to look for clues as to the cause of the problem(s) seen in the baby. Feedback from families suggests that it is best to avoid terms such as dysmorphic, and to use in preference terms such as "distinctive facial features". Families report that the terms abnormal or deformed can be offensive, and that an abnormality is better described as a problem or difficulty.

G. Reference: •

Aase, JM. Diagnostic dysmorphology Plenum Medical Book Company, New York, 1990

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20. IMMEDIATE MANAGEMENT OF THE TINY BABY (1,000G>) A. B. C. D. E. F. G.

Summary Introduction Antenatal corticosteroids Resuscitation Nursery management Areas of Uncertainty in Clinical Practice Reference

A. Summary: - the most experienced staff should care for tiny babies - avoidance of hypothermia/cold stress is paramount - transepidermal water loss should be minimised - volutrauma (secondary to excessive tidal volume) and hyperoxaemia should be avoided - extreme care should be taken with skin attachments B. Introduction: Although in excess of 90% of babies less than 1,000 grams or < 28 weeks gestation are delivered in tertiary centres, occasionally, a tiny baby is delivered in a level 2 (or smaller) hospital. Although it is mandatory to transfer these babies ex utero by NETS to a level 3 NICU, there is ordinarily some delay between delivery and the arrival of the transport team. The following is a guide to the management of the tiny baby pending arrival of NETS. Wherever possible, the most experienced doctors and nurses available should care for these babies. This is particularly important with respect to any procedures. It is also important to contact NETS or level 3 personnel early.

C. Antenatal corticosteroids: Although the effectiveness on fetal lung maturity of steroids administered to the mother less than 24 hours prior is unclear, there are other benefits, for example the prevention of intraventricular haemorrhage. Therefore, even if delivery is thought to be inevitable, treatment with antenatal steroids should always be considered.

D. Resuscitation: - refer to section on resuscitation for general principles - avoidance of hypothermia/cold stress is paramount; heat loss can be minimised by the following: • • • • •

-

-

avoid evaporative heat loss – dry the infant avoid conductive heat loss – ensure that wraps are/remain warm (i.e. replace if necessary) reduce radiant heat loss – manage baby under a radiant heater avoid convective heat loss – avoid drafts, keep baby away from air conditioning ducts N.B. ‘blanketing’ is ineffective in tiny babies as they are unable to generate enough heat to warm the air between the skin and the blanket; bubble wrap between the baby and the overhead heater is preferable as it allows transmission of heat and reduces convective heat loss it is extremely likely that the baby will require endotracheal intubation: • refer to the section on endotracheal intubation • use a 2.5 mm endotracheal tube • oral intubation is recommended if: ƒ the infant is < 26 weeks’ gestation ƒ the tube cannot be easily passed through the nose ƒ the doctor is inexperienced/is having difficulty with nasotracheal intubation an oral tube should be tied at 6.5 to 7.0 cm at the lips a nasal tube should be tied at 7.5 to 8.0 cm at the nares alternatively, if using a Portex tube, the tube should be inserted until the black marker ‘disappears’ beyond the vocal cords it is helpful to check for symmetrical breath sounds once intubated, most tiny babies respond rapidly to IPPV (or bag and mask ventilation if endotracheal intubation is not possible): • IPPV may be provided with: ƒ a ‘Neopuff’ ƒ a Laerdal bag ƒ an anaesthetic bag attached to a manometer (experienced hands only) • aim for a PEEP of 5 cm H20

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• • •

-

use enough PIP to ensure adequate, but not excessive chest wall movement aim to replicate the baby’s endogenous respiratory rate (~ 60 pbm) where ever possible the infant should be placed onto a mechanical ventilator (the ‘Neopuff’ is an alternative) the baby should receive 0.5 mg Vitamin K intramuscularly

E. Nursery management: - procedures should be undertaken under a radiant heater. Once completed, ideally, the baby should be

-

-

-

-

-

placed in a double walled humidified isolette. However, if this is not available, the baby should remain under a radiant heater (servo controlled, if possible). The baby should be covered directly with bubble wrap or indirectly with cling wrap, preferably in a humidified (60-80%) environment – see section on thermoregulation if the baby is placed on a mechanical ventilator, the following settings are recommended: • inspiratory time – 0.35 seconds • expiratory time – 0.65 seconds • respiratory rate – 60 breaths per minute • PEEP – 5 cm H20 • PIP – that required to ensure adequate, but not excessive chest movement the following monitoring guidelines are recommended: • FiO2 – this should be altered to maintain percutaneous SaO2 between 90-95% with alarms set at 88-96% (high saturations may increase the risk of retinopathy of prematurity) • transcutaneous electrodes should be used with caution (e.g. heated to 43 not 44 degrees) as they can strip the immature epidermis • the skin is extremely fragile and liable to break down –the following products help to avoid this trauma but if they are not available remember that it is better to use all available monitoring equipment and standard probe attachments in order to avoid excessive handling of the infant: ƒ hydrogel products should be used for all electrodes and temperature probe placement ƒ hydrocolloid products (e.g Comfeel Coloplast) should be applied under all taping ƒ an elastic non adhesive tape (Coban) should be used to secure pulse oximeter probes and peripheral cannulas a chest x-ray should be organised to ensure correct position of the endotracheal tube and assess the type/severity of lung disease venous access should be obtained • umbilical venous catheter < 26 weeks (this can also be used for sampling) • intravenous cannula (25 gauge) in bigger babies fluids should be commenced at 80 mls/kg/day of 10% dextrose the baby should not be fed if possible, the following blood tests should be performed (to facilitate discussion with NETS): • blood sugar level • blood gas • blood culture because of the high risk of perinatal sepsis, even if a blood culture cannot be taken, intravenous antibiotics should be given (even though many babies may not eventually prove to be septic or have a ‘set up’ for perinatal sepsis): • penicillin 60mg/kg • gentamicin 2.5 mg/kg following discussion with NETS, particularly if the retrieval is to be delayed, and in experienced hands, the baby may be given exogenous surfactant if there are concerns about poor perfusion, then volume expansion in the form of 10 mL/kg 0.9% normal saline should be considered the baby may require inotropic support, although this should follow discussion with NETS blood pressure should be measured every 30 minutes

F. Areas of Uncertainty in Clinical Practice: - the role of limiting tidal volume rather than just pressure in the resuscitation of the tiny infant G. References: • •

Crowley P. Prophylactic corticosteroids for preterm birth. The Cochrane Library 2001 Issue 2 Donoghue D, Cust A. Report of the Australian & New Zealand Neonatal Network: 1999. University of Sydney

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• • • •

Harpin V, Rutter N. Humidity of incubators. Arch Dis Child 1985;60:219-224 Flenady VJ, Woodgate PG. Radiant warmers versus incubators for regulating body temperature in newborn infants. The Cochrane Library 2001 Issue 2 Bucher H, Fanconi S, Baeckert P, Duc G. Hyperoxaemia in newborn infants: detection by pulse oximetry. Paediatrics 1989;84:226-30 Sorm K, Jenson T. Skin care of preterm infants: strategies to minimise potential damage. Journal of Neonatal Nursing 1999;5:13-5

Other Reading/Web links: www.cs.nsw.gov.au/rpa/neonatal/html/newprot/small_baby.htm (for a more detailed discussion of the management of small babies)

21. FETAL HYDRONEPHROSIS A. B. C. D. E. F. G. H.

Management Summary Introduction Definition Differential Diagnosis Postnatal Investigation Management Areas of Uncertainty in Clinical Practice References

A. Management Summary:

B. Introduction: Ultrasonographic examination of the fetus has become a routine examination of pregnancy. Victorian Perinatal Data confirms that 97% of pregnant women undergo antenatal ultrasound1. In 1% of pregnancies a significant structural anomaly is detected. Urological anomalies comprise 30-50% of all fetal abnormalities. An Australian study published by Tam and colleagues in 1994 established an incidence of fetal hydronephrosis of 5.1 per 1000 live births. More recently a prospective UK study identified fetal hydronephrosis in 2.3% of women. The extent to which postnatal investigation of stable minimal hydronephrosis is required remains a debated issue.

C. Definition: No agreed international classification exists. The Australian Society for Ultrasound in Medicine defines hydronephrosis according to gestation by anteroposterior renal pelvic diameter.

18 - 20 weeks

4mm

32 weeks

6mm

Any gestation

10mm (regarded as severe hydronephrosis) 60

80% of fetal hydronephrosis is mild with 20% classified as moderate/severe. The Society for Fetal Urology considers the appearance of the calyces, renal pelvis and parenchyma to grade the degree of hydronephrosis from I - V (minimal to severe).

Calyceal dilatation

Size of Pelvis

Grade 1

Physiological

1 cm

Grade 2

Normal calyces

1 - 1.5 cm

Grade 3

Slight dilatation

> 1.5 cm

Grade 4

Moderate dilatation

> 1.5 cm

Grade 5

Severe dilatation, atrophic cortex

> 1.5 cm

D. Differential Diagnosis: a) fetal hydronephrosis appears to be associated with an excellent prognosis, most likely representing the spectrum of physiological renal pelvic dilatation. b) Persistant moderate or progressive fetal hydronephrosis may be due to: - Pelviureteric junction obstruction (PUJ) - Vesico-ureteric reflux (VUR). c) Severe bilateral hydronephrosis is associated with structural or chromosomal anomaly in 55% of cases. d) Posterior urethral valves in the male fetus- may be suggested antenatally by observation of bladder trabeculation post voiding e) Multicystic, dysplastic kidney may appear as marked hydronephrosis although echogenic foci can usually be seen within the renal margins f) Renal duplications g) Megaureters

E. Postnatal Investigation: -

perform a physical exam to exclude other problems imaging studies

Severe hydronephrosis requires immediate imaging. Investigation of mild/moderate hydronephrosis is better delayed until good urine flow is established (at least 5 - 7 days post delivery).

-

renal ultrasound is required for all infants micturating cystourethrogram is required to exclude VUR isotope renography is required to exclude PUJ obstruction. MAG3 study can be done within 3-5 days of birth whereas DTPA is best delayed to 6 weeks of age when GFR is maximal

F. Management: a) Severe Hydronephrosis: In severe prenatal hydronephrosis joint antenatal consultation with the paediatrician and paediatric urologist may be beneficial in informing parents of likely diagnoses and postnatal course. The possibility of transfer to a tertiary paediatric facility soon after birth to decompress the urological system may need discussion. Oligohydroamnios is an independent predictor of poor outcome because of the association with pulmonary hypoplasia. After birth severe hydronephrosis palpable mass should be referred promptly to a paediatric urologist.

61

b) Mild: When the fetal hydronephrosis is mild or moderate and the infant is to be discharged home prior to confirmatory imaging antibiotic prophylaxis against urosepsis is considered prudent. Eg: Trimethoprim 2mg/kg/day once daily as prophylaxis Once imaging excludes VUR antibiotic prophylaxis can be ceased. If VUR is excluded and the degree of hydronephrosis is moderate, isotope renography is required to exclude PUJ obstruction. If PUJ obstruction is found referral to a paediatric urologist is appropriate. All remaining uncomplicated hydronephrosis can be serially monitored with ultrasonography at 6 - 12 monthly intervals until resolution is documented.

G. Areas of Uncertainty in Clinical Practice: As mild fetal hydronephrosis is associated with an excellent prognosis the extent of postnatal investigation is controversial. Some authors suggest that ultrasonography combined with careful clinical review is all that is required. The place of antibiotic prophylaxis prior to postnatal ultrasound is also questioned. If the infant remains in hospital until the time of ultrasound and/or micturating cystourethrogram some authors suggest that antibiotic therapy is unnecessary in the absence of proven infection. Where prenatal pelvicalyceal dilatation is marked outcome is difficult to predict. The presence of a thin crescent of echogenicity over a distended calyx (the egg-shell sign) may indicate raised intrarenal pressure justifying aggressive management.

H. References: • • • • • • • • • • • • •

Yates J, Lumley J, Bell R. The prevalence and timing of obstetric ultrasound scans. Final report to all Victorian hospitals. Centre for the Study of Mother's and Children's Health, Monash University. 1993. Anderson N, Boswell O, Duff G. Prenatal Sonography for the detection of fetal anomalies: Results of a prospective study and comparison with prior series. Am J Roentgenol 1995;165:943-950. Thomas DFM. Fetal Uropathy. Br J Urol 1990;66:225-31. Tam JC, Hodson EM, Choong KC et al. Postnatal diagnosis and outcome of urinary tract abnormalities detected by antenatal ultrasound. Med J Aust 1994;160:633-37. Sairam S, Al-Habib A, Sasson S and Thilaganathan B. Natural history of fetal hydronephrosis diagnosed on mid-trimester ultrasound. Ultrasound Obstet Gynaecol 2001;17:191-6. Dudley JA, Haworth JM, McGraw ME, Frank JD, Tizard EJ. Clinical relevance and implications of antenatal hydronephrosis. Arch Dis Child 1997;76:F31-34. Grignon et al. Urinary tract dilatation in utero: classification and clinical applications. Radiology 1986; 60:645-7 Elder JS. Antenatal Hydronephrosis. Fetal and neonatal management. Pediatr Clin North Am 1997;44:1299-1321. Oliveira EA et al. Prognostic factors in fetal hydronephrosis:a multivariate analysis. Pediatr Nephrol 1999;13:859-64. Harding LJ, Malone PS, Wellesley DG. Antenatal minimal hydronephrosis: is its follow-up an unnecessary cause for concern? Prenat Diagn 1999;19:701-5. Yerkes EB, Adams PC, Pope JC 4th, Brock JW 3rd. Does every patient with prenatal hydronephrosis need voiding cystourethrography? J Urol 1999;162:1218-20. Jones CL, Walker RG, Powell HR. Recent Advances in the management of vesico-ureteric reflux. J Paediatr Child Health 1993;29:325-7. Dewan PA, Anderson K. The egg-shell sign: a possible indicator of raised intrarenal pressure. Pediatr Surg Int 2000;16:527-8.

62

22. GASTRO-OESOPHAGEAL REFLUX A. B. C. D. E. F. G. H.

Summary Introduction When might GOR be pathological? Differential Diagnosis (of vomiting) Diagnosis of GOR Management Areas of Uncertainty in Clinical Practice References

A. Summary: -

some GOR occurs in most premature infants, but it is usually not pathological a 24-hour pH probe study is the gold standard for the diagnosis of occult GOR, but requires the gastric contents to be acidic non-pharmacological measures should be adopted first in the treatment of GOR pharmacological treatment of GOR should only be undertaken where there is proven, pathological reflux

B. Introduction: Gastro-oesophageal reflux (GOR) may be defined as the spontaneous effortless regurgitation of gastric contents into the oesophagus. This may or may not result in vomiting. Although some (physiological) reflux occurs in most premature infants, the total amount of reflux in a 24-hour period is usually not grossly abnormal. Preterm infants appear to have fewer and shorter episodes of reflux than term infants. Therefore, the investigation and management of GOR in the neonatal nursery should be reserved for those infants in whom the reflux is considered to be pathological.

C. When might GOR be pathological? - delayed acid clearance resulting in: • •

-

-

bleeding stricture (incidence unknown) pulmonary complications: • apnoea (however, most apnoea is not due to GOR) • aspiration • exacerbation of chronic lung disease in some cases failure to thrive, secondary to poor intake apparent life-threatening events and SIDS (controversial)

D. Differential Diagnosis (of vomiting): -

drugs e.g. theophylline and caffeine inborn errors of metabolism pyloric stenosis (GOR usually not projectile) bowel obstruction (usually bile-stained vomiting) sepsis (especially UTI) necrotising enterocolitis

E. Diagnosis of GOR: -

usually clinical barium swallow and ultrasound nonspecific (only useful to rule out structural abnormalities) 24-hour pH probe gold standard, although gastric contents must be acid demonstration of acid in oral secretions by using litmus paper (wont diagnose reflux into lower oesophagus) white oral secretions may be differentiated from milk if milk is tinged with methylene blue (few drops only) endoscopy little data available for preterm infants radio-nucleotide studies not standardised in preterm infants oesophageal manometry catheter size limits usefulness in VLBW

63

F. Management: -

Non-pharmacological: • prone +/- 30-degree elevation (beware increased risk of SIDS if prone - apnoea monitoring required), alternatively left side down • increased frequency (thus decreased volume) of feeds • indwelling vs. intermittent tube insertion • continuous feeding (gastric or transpyloric) • thickeners including Karicare, Carobel, Gaviscon • fundoplication (reserved where intractable or life-threatening proven GOR and failed pharmacological therapy)

-

Pharmacological only for proven, pathological GOR: • Antacid therapies e.g. Gaviscon, Mylanta • H2 blockers e.g. Ranitidine • Proton pump inhibitors e.g. Omeprazole (expensive)

G. Areas of Uncertainty in Clinical Practice: -

the role of GOR in the aetiology of SIDS reflux-specific behavioural criteria (e.g. discomfort, head retraction and mouthing) may be inappropriate as diagnostic criteria for GOR in premature infants

H. References: • • •

Novak DA. Gastroesophageal reflux in the preterm infant. Clin Perinatol 1996;23:305-20 Vandenplas Y, et al. The role of cisapride in the treatment of pediatric gastroesophageal reflux. A medical position statement of the European Society of Pediatric Gastroenterology, Hepatology and Nutrition. J Pediatr Gastroenterol Nutr 1999;28:518-28 Gilbert RE, et al. Cisapride treatment for gastro-oesophageal reflux in children: A systematic review of randomized controlled trials. J Paediatr Child Health 2000;36:524-9

Other Reading/Web links: • • • • •

Orenstein SR. Gastroesophageal reflux. Pediatrics in Review 1999;20:24-8 Lander A. The risks and benefits of cisapride in premature neonates, infants, and children. Arch Dis Child 1998;79:469-70 Badriul H, Vandenplas Y. Gastro-oesophageal reflux in infancy. J Gastroenterol Hepatol 199;14:13-9 Page M, Jeffery H. The role of gastro-oesophageal reflux in the aetiology of SIDS. Early Hum Dev 2000;59:127-49 Newell SJ, Booth IW, Morgan MEI, et al. Gastro-oesophageal reflux in preterm infants. Arch Dis Child 1989;64:780

23. PREVENTION OF GBS SEPSIS A. Antenatal Strategies: Women at high risk of GBS carriage at delivery and assumed to potentially have GBS (therefore not screened): -

GBS grown from urine or vaginal swabs in current pregnancy Previous pregnancy with a GBS infected neonate Previous GBS carriage

Screen all remaining women for GBS carrier status: -

Screening best performed at 34-36 weeks’ gestation to enable result to be processed but still reflective of flora at term Vaginal AND Perianal swabs will lead to fewer false negatives

64

B. Intrapartum Strategies:

C. Neonatal Strategies:

Further information regarding antibiotic dosage and duration is available in Sepsis section

65

24. GLUCOSE-6-PHOSPHATE DEHYDROGENASE DEFICIENCY A. B. C. D. E. F. G.

Introduction Differential Diagnosis Investigation Management References Parent Information handout Reference

A. Introduction: G6PD is a cytoplasmic enzyme in the hexose monophosphate pathway responsible for the production of glutathione. It helps to protect the red blood cell from oxidative damage. The G6PD gene lies on the X chromosome, and over 300 mutations have been described. Therefore, G6PD deficiency is a common X-linked recessive genetic disorder affecting: - 1 in 50 southeast Asians - 1 in 10 Mediterranean families (Italian, Greek, and Middle Eastern) - 1 in 10 African-American. Because of the high gene frequency in some regions, homozygous affected females are not uncommon. Females may also be affected through Lyonisation or if they have Turner’s Syndrome. There are 3 major clinical disorders: - neonatal hyperbilirubinaemia - chronic haemolytic anaemia - induced haemolytic anaemia: • naphthalene (mothballs) • sulphonamides • nitrofurans • aspirin • fava (broad) beans • viral infection Newborn infants with immature and deficient enzyme pathways are at greater risk of developing haemolytic anaemia than adults. However, neonates usually present with jaundice in the absence of anaemia. Jaundice can be severe and result in kernicterus.

B. Differential Diagnosis: Causes of haemolytic anaemia: - maternal-fetal blood group incompatibilities: • rhesus isoimmunisation • ABO incompatibility - other red cell enzyme deficiencies (eg pyruvate kinase) - red cell membrane disorders (eg hereditary spherocytosis) - disorders of haemoglobin synthesis (eg alpha thalassaemia group of disorders)

C. Investigation: -

-

likely findings suggesting further investigation required include: • unconjugated hyperbilirubinaemia • Heinz bodies noted on FBE • increased reticulocyte count • negative direct anti-globulin titre (Coombs) test diagnostic: • G6PD screen then assay

D. Management: -

treatment of hyperbilirubinaemia: phototherapy and/or exchange transfusion (may be required at a lower threshold as haemolysing) confirmation of diagnosis educate parents about G6PD deficiency and avoidance of triggers (especially mothballs)

66

E. Parent Information handout: Dear Your baby has been found to have a condition called Glucose–6 Phosphat Dehydrogenase deficiency. This condition is also called G6PD deficiency. G6PD deficiency is an inherited condition of the red blood cells. It is most often found in children from families of Mediterranean or South East Asian origin. It is important to know that G6PD deficiency will not affect the normal development and health of your child. There are a few substances that may cause break down of the red blood cells if your child comes in contact with them. The rapid break down of red blood cells causes anemia. Apart from avoiding these substances the G6PD deficiency does not cause other troubles and does not need any treatment. You should ask your doctor if you want more information. If there are any other children in the family who have not been tested for G6PD deficiency your doctor can arrange this for them. The following substances should be avoided: • Moth balls and Napthalene Anything stored in mothballs should be washed before it comes near your baby. When your child is older, do not let him handle moth balls. • Broad Beans (also called Fava Beans or Vicia Fava) This is the only food that should be avoided. All other types of beans are safe. • Aspirin (also called acetyl salicylic acid) Large amounts of aspirin affect children with G6PD deficiency. Paracetamol is the preferred medicine for relief of pain or fever in children. • Medicines prescribed by your doctor Some medicines may affect people with G6PD deficiency including nitrofurantoin, probenecid, phenacetin, suphonamides, chloroquine, primaquine, para-amino salicylic acid. Show your doctor this letter before any medicine is prescribed for your child.

F. References: •

Balnchette V, Doyle J, Schmidt B, Zipursky A. Hematology. In Neonatology: Pathophysiology and Management of the Newborn, 4th ed. Philadelphia: JB Lipincott Co 1994; 952-999

Web links: • •

www.cs.nsw.gov.au/rpa/neonatal/html/newprot/rhesus.htm (look under 'Other Causes of Haemolytic Jaundice) www.aap.org

25. HEADBOX OXYGEN SET-UP A. B. C. D. E. F. G.

Introduction Equipment Procedure Complications Cleaning of Equipment Areas of uncertainty in clinical practice References

A. Introduction: The headbox is a clear plastic hood that surrounds the baby’s head, and has an opening for the baby’s neck, which leaves the body accessible for nursing care. The headbox maintains a stable concentration of warm and humidified oxygen that is titrated to achieve the desired oxygen saturation.

B. Equipment: - oxygen blender/oxygen & air flow meters with nipples - green oxygen tubing - humidifier base, water chamber & sterile water for irrigation - heater hose/corrugated tubing - headbox (with sponge, optional) - headbox thermometer - oxygen analyser 67

C. Procedure: - assemble the humidifier base and water filled chamber - connect the oxygen tubing from the oxygen blender to the water filled chamber. Alternatively connect -

tubing from oxygen and air flow meters via a "Y" connector and then attach the single piece of tubing from the "Y" connector to the water filled chamber connect the heater hose to the water filled chamber secure the headbox thermometer to the inside of the headbox. If possible, insert spnge over gas inlet place the headbox over the baby’s head, taking care when positioning the headbox around the baby’s neck connect the heater hose to the headbox blend the oxygen to obtain the necessary oxygen concentration to achieve the desired oxygen saturation. The total flow of gases should be at least 6 to 8 L/min to prevent accumulation of carbon dioxide in the headbox desired oxygen concentrations are achieved either via a blender "dialled" to the appropriate concentration, or by combining the flow of oxygen and air using the following guide

Headbox oxygen/air flow rates:

Oxygen percentage

Oxygen flow (L/min)

Air flow (L/min)

30

1

9

40

2

8

50

4

6

60

5

5

70

6

4

80

7.5

2.5

90

9

1

-

calibrate oxygen analyser and place into the headbox, alongside the baby’s nose maintain the inspired gas temperature at the appropriate neutral thermal environment for the baby Continuously assess and document hourly the following: - inspired oxygen concentration - oxygen saturation ( hourly) - heart rate - respiratory rate and effort - headbox temperature - water level in chamber - humidification (dry or moist) - observe the baby’s neck for irritation and pressure areas hourly, and ensure the position of the headbox is correct - remove any accumulated water in the heater hose hourly - calibrate the oxygen analyser every eight hours - check the baby’s temperature hourly for four hours or until stable when headbox oxygen commences and then four hourly

D. Complications: -

hypoxaemia hyperoxaemia hypothermia hyperthermia irritation and pressure to neck

68

E. Cleaning of Equipment: - change the headbox circuit, humidifying chamber and headbox when the 2 litre bag of water is empty - the heater/humidifier is wiped clean with disinfectant - the headbox and thermometer are washed with detergent and rinsed thoroughly. F. Areas of uncertainty in clinical practice: When to transfer an infant from incubator or intra-nasal flow oxygen will depend on: - the clinical situation - the concentration of oxygen required - the operational characteristics of the incubator being used. As a general guide infants requiring 40% oxygen or more will usually be managed with headbox oxygen. Optimally oxygen delivered by headbox should be warmed and humidified, however, during the immediate stabilisation of a sick infant consistency of oxygenation remains the priority.

G. References: • • •

Aloan, C.A. & Hill, T.V. (1997). Respiratory care of the newborn and child (2nd ed). Philadelphia: Lippincott. Askin, D.F. (1997). Acute respiratory care of the neonate: A self study course (2nd ed). Petaluma: NICU INK. Barnhart, S.L. and Czervinske (1995). Perinatal and pediatric respiratory care. Philadelphia: W.B. Saunders.

26. HYPOGLYCAEMIA A. B. C. D. E. F. G. H.

Summary Introduction Diagnosis Investigation Prevention Management Areas Of Uncertainty In Clinical Practice Reference

A. Summary: - there is a lack of consensus on the definition of hypoglycaemia - reagent stick screening of blood glucose concentrations is not accurate at low levels - most asymptomatic infants can be initially fed an increased volume of milk, and only if hypoglycaemia -

persist should an IV glucose infusion be started without a good evidence base for patient management, operational thresholds can be used to guide clinical practice

B. Introduction: Management of hypoglycaemia is complicated by:

-

a lack of consensus on its definition an inherent inaccuracy of reagent sticks being mostly asymptomatic or having symptoms that are non-specific a lack evidence from randomised clinical trial with long-term outcome data

C. Diagnosis: Infants with the following clinical features should have their blood glucose checked: - CNS excitation: • jitteriness • high-pitched cry • seizures - CNS depression: • lethargy • apnoea • poor feeding

69

Since the majority are asymptomatic, infants at risk for hypoglycaemia should also have their blood glucose checked on arrival in the nursery:

-

reduced glycogen stores or increased glucose demands: • prematurity • IUGR • perinatal asphyxia • hypothermia • RDS • sepsis

-

hyperinsulinaemic states: • infants of diabetic mothers • Rhesus isoimmunisation • Beckwith-Weidemann syndrome: ƒ microcephaly ƒ umbilical hernia ƒ macroglossia ƒ hypoglycaemia • islet cell hyperplasia • pancreatic tumour

D. Investigation: - reagent sticks used for screening may overestimate the occurrence of hypoglycaemia. It is important to -

confirm suspected hypoglycaemia with a true blood glucose estimation on at least one occassion. the infant of a diabetic mother and those admitted to intensive care should have screening performed promptly after arrival in the nursery. For other at risk infants testing should be performed at three hours of age and continue three hourly until 2 successive readings >2.6mmol/L are obtained. infants with blood glucose < 2.6 mmol/L should have hourly blood glucose determinations until stable >2.6mmol/L. large normally grown and nourished premature infants who can be fed early after birth generally will only require screening before the first two 3 hourly feeds. Other at risk infants require continued screening before every second feed until 24 hours of age. congenital adrenal hyperplasia can present with hypoglycaemia. Failure to investigate and promptly treat these cases of ambiguous genitalia can be disastrous if > 20 mg/kg/min of IV glucose is required for normoglycaemia in the first few days, or if > 12 mg/kg/min is required after that age, initiate diagnostic steps for hyperinsulinism. When the true blood sugar is < 2.0mmol/L, test urine for ketones and send venous or arterial blood for:

• • • • •

glucose insulin growth hormone cortisol free fatty acids

E. Prevention: If able to take enteral feeds, commence by 1-2 hours of age. Feed frequently either 2 hourly or 3 hourly if risk is low. Use full strength formula at 60 mL/kg initially, increase to 90 mL/kg by 24 hours according to tolerance. If only able to have IV fluid, commence 10% dextrose at 60-90mls/kg/24 hours (4-6 mg/kg/min of glucose). If fluid restriction is required increase the concentration of dextrose in the infusion.

F. Management: Oral Feeds. If a hypoglycaemic infant is able to tolerate enteral feed, this should be given and the blood glucose determined an hour later and before next feed. IV Glucose. If the infant is unable to tolerate enteral feeds or if there is no response to the above measure:

- An IV bolus of 200-300 mg/kg glucose (2-3 ml/kg of 10% dextrose) This is followed by a continuous IV infusion of 10% dextrose at 120 mL/kg/d (8 mg/kg/min glucose) to prevent rebound hypoglycaemia. If fluid restriction is necessary, give more concentrated dextrose solution (up to 15% with peripheral IV). IV infusion of solutions with >12.5% dextrose are best given through a central line in order to aviod complications. - Once the blood glucose normalises, enteral feeds can be reintroduced and the infusion tailed off. - Prescription to make up a 50mL solution of various dextrose infusions 70

Infusion Concentration

Volume of 10%Dextrose

Volume of 50%Dextrose

12.5%

46.5mL

3.5mL

15.0%

44.0mL

6.0mL

17.5%

40.5mL

9.5mL

20.0%

37.5mL

12.5mL

Glucagon. In infants with adequate glycogen stores (e.g. hyperinsulinaemic states) whose hypoglycaemia persists in spite of an IV infusion: An IM statim injection of glucagon 0.3 mg/kg (0.3 u/kg). This may be repeated once only if there is good initial response.

-

If hypoglycaemia recurs or persists despite IV infusion of 15% dextrose at 120ml/kg/d (12mg/kg/min glucose), an IV glucagon infusion should be considered (1-2 mg/kg/d) while arrangements are made to transfer the infant to a Level 3 centre for continued treatment.

Other Treatments. Corticosteroids (eg Hydrocortisone, 5-10mg/kg/24hours IM/IV, or Dexamethasone) are required rarely in severe hypoglycaemia to raise blood glucose levels. The use of diazoxide and pancreatic surgery is extremely rare, but may need to be considered in profound intractable hypoglycaemia secondary to hyperinsulinism. The cause of hypoglycaemia (e.g. hypothermia, sepsis) must also be treated.

G. Areas Of Uncertainty In Clinical Practice: - In the 1960s neonatal hypoglycaemia was diagnosed only in symptomatic infants with two true blood

-

-

glucose level <1.5 mmol/l. Since then, reagent stick screening has replaced true blood glucose measurements. With an increasing number of lawsuits, and with publication of studies in the late 1980s, the definition of hypoglycaemia has been changed to include asymptomatic infants with one screening blood glucose level <2.6 mmol/l. This contradicts experimental animal evidence: 30 minutes of isoelectric EEG/> • neurochemical endpoint: excess glutamate release from neurons only if blood glucose is <0.7 mmol/l associated with >15 minutes of isoelectric EEG • neurodevelopmental endpoint: intact survival even with blood glucose <0.9 mmol/l for 10 hours • Nevertheless, the definition for hypoglycaemia has progressively shifted: <1.5 mmol/l (1959-69), <2.2 mmol/l (1970-87), <2.6 mmol/l (1988-98), and in the USA now where lawsuits continue to multiply and succeed, <3.2 mmol/l (since 1999) Cornblath has recommended that hypoglycaemia should not be defined by a blood glucose level, as hypoglycaemia implies disease. Rather, neonatal practice should be guided by an ‘operational threshold’ for an appropriate clinical response, which he has suggested as follow:

Asymptomatic infants: < 2.0 mmol/l Symptomatic infants:

< 2.6 mmol/l

Sick infants:

< 2.6 mmol/l

IV therapy:

< 1.5 mmol/l

H. References: • •

Koh THHG, Aynsley-Green A, Tarbit M, Eyre JA. Neural dysfunction during hypoglycaemia. Arch Dis Child 1988;63:1353-1358. Lucas A, Morley R, Cole TJ. Adverse neurodevelopmental outcome of moderate neonatal hypoglycaemia. Br Med J 1988;297:1304-1308.

Other Reading: • •

Hawdon JM, Aynsley-Green A. Metabolic disease. In: Rennie JM, Roberton NRC (eds). Textbook of Neonatology, 3rd edition. Churchill Livingstone, London, 1999, pg. 939-956. Cornblath M. Hypoglycaemia. In: Proceedings of Special Ross Conference, Hot Topics in Neonatology, Washington DC, 2000.

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27. HYPOSPADIAS A. B. C. D. E. F.

Summary Introduction Differential Diagnosis Investigation Management References

A. Summary: - no immediate management is necessary as long as the testes are descended and there is a good urinary -

stream all cases should be referred to a paediatric surgeon

B. Introduction: Hypospadias is a common condition which affects 1 in 300 newborn males. It is more common in growth retrictred males. The clinical findings in hypospadias are as follows: - the urethra opens on the ventral surface of the penis and does not reach the tip of the glans. In mild cases the meatus is at the base of the glans. In severe cases the urinary meatus may open in the scrotum or perineum - the prepuce lacks ventral tissue so is hooded - all but the mildest cases involve some degree of chordee. Chordee is a lack of ventral tissue on the penis leading to a bowstring effect causing longitudinal bending of the shaft

C. Differential Diagnosis: If present with undescended testes an intersex disorder should be considered. Gender assignment should be delayed until the sex of rearing has been decided. Urgent expert assessment is required (see section on management of ambiguous genitalia).

D. Investigation: Careful examination is required since hypospadias is associated with a large number of other anomalies and syndromes. Infants with penoscrotal or perineal abnormalities should be assessed to exclude intersex disorders.(see section on management of ambiguous genitalia).

E. Management: -

no immediate management is required as long as the meatus is not stenosed and there is a good urinary stream the parents should be advised not to circumcise the child as the prepuce is sometimes used in reconstructive surgery referral should be made to a paediatric surgeon. To reduce the psychological impact surgical correction is usually performed in infancy, if possible, as a one-stage procedure. Occasionally surgery is not required. If a chordee is present surgical correction is required because when standing there will be difficulty with directing urinary stream. Intercourse may also be difficult or painful because the chordee is accentuated during an erection

F. References: • • •

Hutson, J.M., Woodward, A.A., and Beaseley, S.W. (editors). Jones’ Clinical Paediatric Surgery. 5th edition. Blackwell Science Pty Ltd. 1999. Smart, J. (editor). Paediatric Handbook. 6th edition. Blackwell Science Pty Ltd. 2000. Balfour-Lynn, I.M. and Valman, H.B.V. Practical Management of the Newborn. 5th edition. Blackwell Science Pty Ltd. 1993.

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28. HYPOTHYROIDISM A. Summary B. Congenital C. Transient Neonatal Hypothyriodism

A. Summary: -

transient disorders of thyroid function are more common than true congenital hypothyroidism (especially in preterm infants) when TSH levels are elevated treatment with thyroxine (either long or short term) is usually indicated

B. Congenital: In Australia the incidence is 1 in 3000-3500 with some geographic variation. - 75% due to dysgenesis: • agenesis • ectopia - 10% due to dyshormonogenesis: • often autosomal recessive • Pendred's syndrome = peroxidase deficiency associated with sensorineural deafness - 5% due to hypothalamic-pituitary (H-P) deficiency: • secondary hypothyroidism • tertiary hypothyroidism - 10% due to transient hypothyroidism: • iodine exposure • maternal antithyroid antibodies

1. Presentation:

-

-

the usual mode of presentation is by the presence of an elevated TSH detected on the day 3 screen (except in secondary or tertiary disease) neonates are often subclinically affected and only detected on routine screening clinical features include: • dry skin • hoarse cry • puffy face • prominent tongue • listless • umbilical hernia • hypothermia • bradycardia • failure to thrive neonates may also present with jaundice due to an unconjugated hyperbilirubinaemia (glucronyl transferase deficiency) gene mutations have been implicated in all forms of congenital hypothyroidism and in some cases result in an expanded phenotype including respiratory distress, choanal atresia, renal malformation and mental delay (independent of degree of hypothyroidism)

2. Investigation: Confirmatory investigations include:

-

repeat T4 and TSH levels thyroid scan (showing absent, lingual or increased uptake of radioisotope) X-ray distal femoral epiphysis (absence implying prolonged/prenatal hypothyroidism) assessment and imaging of pituitary gland, if indicated

3. Management: Thyroxine replacement therapy should be commenced as soon as possible at a dose of 8-10 microgm/kg/day in a single daily dose. Tablets should be ground up between two teaspoons and mixed with a few drops of milk. This solution should be transferred to a small, plastic feeding spoon and deposited on the back of the tongue immediately prior to feeds.

73

4. Prognosis: The prognosis is usually one of normal intellectual and physical development if treatment is commenced promptly and monitored closely. Over treatment may result in craniosynostosis and has been implicated in causing attention deficit hyperactivity disorder.

C. Transient Neonatal Hypothyriodism: This group of conditions can be subdivided into 4 main categories. Cause and biochemical profiles are listed in the table below. 1.

2.

3.

4.

Transient Hypothyroxinaemia: o low serum T4 levels seen in approx. 50%of infants delivered before 30 weeks gestation o normal or low TSH levels o corrects spontaneously over 4-8 weeks o no treatment required Transient primary hypothyroidism: o low serum T4 levels and high TSH levels o seen in approx. 20%of premature infants (incidence increases as gestation decreases) o usually develops within 1-2 weeks ex-utero and often superimposed upon transient hypothyroxinaemia o repeated screening cards should be sent on all infants <30wks (at 48hrs and then again at 28days) o hypothyroidism may persist for 2-3 months o treatment recommended Transient hyperthyrotropinaemia: o rare (1 in 16-19,000 births) o elevated TSH for 3-9 months before reducing spontaneously o no treament required but need careful follow-up to exclude partial dyshormonogenesis or ectopia Low T3/T4 syndrome ("sick euthyroid") : o non-thyroidal illness

T3 Low T3 syndrome

T4

TSH

N

N

Low T4 syndrome

N

no treament required

Causes and biochemical profiles of transient neonatal hypothyroidism

Serum levels of T4 Transient hypothyroxinaemia

Causes

TSH N

Immaturity of H-P axis (<30 wks gest'n)

Transient primary

Maternal anti-hypothyroidism thyroid therapy, iodine deficiency, maternal Ab's, idiopathic

Transient hyperthyrotropinaemia

Erroneous assay, iodine deficiency or excess, idiopathic

Low T3/T4 syndrome

N

N or

N

Prematurity, surgical stress, sepsis, malnutrition

Further Reading : Pediatric Endocrinology Sperling MA, WB Saunders 1996, Philadelphia

74

29. IMMUNISATION OF PRETERM INFANTS A. B. C. D. E. F. G. H. I. J. K.

Introduction Immunisation schedule Adverse Events Following Immunisation Observation after vaccination Cardiorespiratory monitoring after vaccination Anaphylaxis Management of anaphylaxis Common Minor Adverse Events Storage of Vaccines Areas of Uncertainty in Clinical Practice Reference

A. Introduction: Preterm babies should be vaccinated according to the recommended schedule, without correction for prematurity, provided that they are well and that there are no contraindications. They have a special need for protection against infectious agents such as pertussis. Vaccination commenced before discharge ensures the development of some degree of protection from infectious agents prevalent within the community. Preterm babies do not have a higher incidence of adverse reactions following immunisation. Some preterm babies, especially those born before 32 weeks do not mount a protective antibody response following immunisation with hepatitis B and Hib vaccines.

B. Immunisation schedule: AGE

Infection prevented

Gestation at birth (weeks) <28 weeks <28 weeks

28 - 32 weeks

>32 weeks

Birth

Hepatitis B

Hep B a

Hep B *

Hep B

2 months

Diphtheria, Tetanus & Pertussis

DTPa

DTPa

DTPa

H. influenza & Hepatitis B

Hib-hep B – COMVAX

Hib-hep B – COMVAX

Hib-hep B COMVAX

Meningococcus

MenCCV

MenCCV

MenCCV

Poliomyelitis

IPV

IPV

OPV

Pneumococcus

7Vpcv

7Vpcv

7vPCV

Diphtheria, Tetanus & Pertussis

DTPa

DTPa

DTPa

H. influenza & Hepatitis B

Hib-hep B – COMVAX

Hib-hep B – COMVAX

Hib-hep B COMVAX

Meningococcus

MenCCV

MenCCV

MenCCV

Poliomyelitis

OPV

OPV

OPV

Pneumococcus

7vPCV

7vPCV

7vPCV

4 months

75

6 months

Diphtheria, Tetanus & Pertussis

DTPa

DTPa

DTPa

Meningococcus

MenCCV

MenCCV

MenCCV

H. influenza & Hepatitis B

Hib-hep B COMVAX

Hepatitis B

Hep B

Poliomyelitis

OPV

OPV

OPV

Pneumococcus

7Vpcv

7vPCV

7vPCV

B Hib-hep B COMVAX

B Hib-hep B COMVAX

B Hib-hep B COMVAX

MMR

MMR

DTPa

DTPa

DTPa

VAricella-zoster (chickenpox) vaccine

VZ

VZ

VZ

Diphtheria, Tetanus & Pertussis

DTPa

DTPa

DTPa

Measles, mumps & Rubella

MMR

MMR

MMR

Poliomyelitis

OPV

OPV

OPV

12 months H. influenza & Hepatitis

Measles, Mumps & Rubella MMR 18 months Diphtheria, Tetanus & Pertussis

4 years

Notes: a. For hepatitis B vaccination at 32 or more weeks there are two alternative recommendations. The first immunisation can be given at the time of birth or the first immunisation can be delayed and given at 2 months postnatal age. However, infants whose mothers are hepatitis B surface antigen positive (HbsAg +ve) should receive the hepatitis B vaccine on the day of delivery. In addition, they should also be given hepatitis B immunoglobulin (HBIG 100 Units, 0.5 mL intramuscularly) within 12 hours of birth b. Wherever possible the same brand of DTPa should be used at 2, 4 and 6 months. c.

Babies born < 28 weeks gestation receive an extra dose of hepatitis B vaccine and Haemophilus influenza vaccine at 6 months of age.

d. Babies born between 28 and 32 weeks gestation receive an extra dose of hepatitis B vaccine at 6 months of age. e.

Adolescent hepatitis B Vaccination is not necessary for those children who have previously received three doses of hepatitis B vaccine.

f.

Varicella Zoster vaccine is recommended at 18 months but is not funded under the Vaccination Schedule.

g. Inactivated Polio Vaccine (IPV) containing combination vaccines at 2,4, 6 months and four years is preferable to Oral Polio Vaccine (OPV), subject to the availability of IPVcombination vaccines, but both IPV and OPV are acceptable for out-patient use in the Australian Standard Vaccination Schedule. 76

h. All doses are 0.5 mL and all vaccines are given IM except IPV, which is given by deep subcutaneous injection. i.

The 7-valent pneumococcal conjugate vaccine (7vPCV) is recommended for all Australian children but is only funded in the following circumstances: -

-

-

-

All Aboriginal and Torres Strait Islander children under the age of 2 years throughout Australia Aboriginal children in Central Australia between 2 and 5 years of age; plus NonAboriginal children in Central Australia under 2 years of age. Children with certain medical conditions which predispose them to invasive pneumococcal disease. These medical conditions require confirmation for the vaccine from a paediatrician. Diseases compromising immune response to pneumococcal infection: congenital immune deficiency including symptomatic IgG subclass or isolated IgA deficiency but excluding children where monthly immunoglobulin infusion is required Diseases associated with immunosuppressive therapy or radiation therapy (including corticosteroid therapy equivalent to greater than 2mg/kg of prednisone for more than 4 weeks) where there is sufficient immune reconstitution for vaccine response to be expected Compromised splenic function due to sickle haemoglobinopathies or congenital or acquired asplenia HIV infection renal failure or relapsing or persistent nephrotic syndrome. Anatomical abnormalities associated with higher rates or severity cardiac disease associated with cyanosis or cardiac failure proven or presumptive cerebrospinal fluid leak. children born before 28 weeks gestation children with chronic lung disease following complications of prematurity (who may have been born > 28 weeks gestation). Down's syndrome insulin dependant diabetes cystic fibrosis intracranial shunts cochlear implants

C. Adverse Events Following Immunisation: Surveillance for adverse events following vaccination is an integral part of the national vaccination program. An adverse event is a serious, uncommon or unexpected event following immunisation. Such an event may be caused by the vaccine or may occur by chance after immunisation. Any event that is considered serious or unexpected and possibly related to the vaccination should be reported to the Australian Adverse Drug Reactions Advisory Committee (forms are available from Hospital Pharmacies). Adverse events include: - anaphylaxis - abscess formation - encephalitis - acute flaccid paralysis - fever (> 40.5C) - persistent screaming - severe local reactions - seizures - any other severe or unusual events

77

D. Observation after vaccination: Recipients of vaccines should remain under observation for a short interval (15 minutes). Most life threatening adverse events begin within 10 minutes of vaccination. The most important immediate reaction to vaccination is anaphylaxis. The incidence of true anaphylaxis to DTP containing vaccines is 1-3 cases per million vaccinations. Hypotonic-hyporesponsive episodes in children do not usually occur immediately after vaccination (usually 4-24 hours post vaccination).

E. Cardiorespiratory monitoring after vaccination: There is an increased incidence of cardiorespiratory instability following immunisation of preterm infants. Apnoea has been reported in 30% of infants born at less than 31 weeks gestation following immunisation at approximately 2 months post natal age with whole cell DTP and HiB. It has been recommended that the cardiorespiratory function of hospitalized infants born at less than 31 weeks gestation is monitored for 48 hours post immunization. Following the introduction of T acellular DTP (Infanrix) the incidence of cardiorespiratory instability following immunisation has substantially fallen.

F. Anaphylaxis: Anaphylaxis following immunisation is very rare. Anaphylaxis is a severe adverse event of rapid onset, characterised by circulatory collapse. Signs of anaphylaxis include: - circulatory collapse: • loss of consciousness • pallor • weak pulse - rapid development of urticarial lesions (elevated red lumps with raised edges and pale centres) - signs of upper airway obstruction: • stridor • weak cry

G. Management of anaphylaxis: -

call for help administer oxygen (6 litres per minute via face mask) commence positive pressure ventilation if the respirations are slow or stop administer adrenaline if the baby is unconscious and commence external cardiac massage if the heart rate is < 60 beats per minute

Adrenaline Concentration

1:10,000

Dose

0.1 mL/kg

Route of administration

IM, IV, ET tube

Frequency

Every 5 minutes until cardiac output is established

H. Common Minor Adverse Events: The following adverse events are frequent but not serious although they can be distressing for parents. These adverse events do not contraindicate further vaccination and do not need to be reported. Transient minor events include: - soreness at the injection site (5%-15%) - fever (2% - 3% - usually low grade) - nausea - dizziness - malaise - myalgia - arthralgia

78

I. Storage of Vaccines: Safe vaccine storage when using a domestic refrigerator The "cold-chain" is the system of transporting and storing vaccines within the safe temperature range (20C to 80C) from the place of manufacture to the place of administration. A "frost free" rather than a cyclic type refrigerator is recommended for storage of vaccines because they have less temperature fluctuations. Because they have a number of different temperature zones they are not designed for the special temperature requirements of vaccines. However they can be used for safe vaccine storage if the following are adhered to:

-

the refrigerator is used for vaccine storage only door openings are kept to a minimum minimum and maximum temperatures are checked and recorded daily at around the same time food or drink are not stored in the vaccine refrigerator vaccines should be stored on the middle and upper shelves an uninterruptable power supply is available during defrosting or cooling, the vaccines are moved to a second refrigerator

J. Areas of Uncertainty in Clinical Practice: - There is little data regarding the immunological responses of extremely preterm infants receiving steroids

-

-

for the treatment of chronic lung disease. Live vaccines (eg Sabin) should not be administered to babies receiving prednisolone (2 mg/kg/day for more than 1 week or 1 mg/kg/day for more than 1 month) or the equivalent dose of dexamethasone. It is unclear if all babies <32 weeks should receive hepatitis B immunisation at birth. Uncertainty has arisen because of the diminished antibody response in this group of babies. However delaying the immunisation may increase the risks of hepatitis B infection during a stage when the infants are exposed to blood products and require invasive methods of treatment.
It is anticipated that from 2003, inactivated polio vaccine (IPV) will replace Sabin as the preferred means of poliomyelitis immunisation. It is anticipated that IPV will be incorporated into another multi-component vaccine e.g. Infanrix.

K. References: • • • • • • •

The Australian Immunisation Handbook. 7th edn. Canberra: NHMRC, 2000. D'Angio CT. Immunization of the premature infant. Pediatr Infect Dis 1999 18:824-825. Khalak R, Pichichero M, D'Angio C. Three-year Follow-up of Vaccine Response in Extremely Preterm Infants. Pediatrics 1998;101:597-603. Slack M, Schapira D. Severe apnoeas following immunisation in premature infants. Arch Dis Child Fetal Neonatal Ed 1999;81:F67-F68. Golebiowska M, Kardas-Sobantka D, Chlebna-Sokol D, Sabanty W. Hepatitis B vaccination in preterm infants. Eur J Pediatr 1999 Apr;158(4):293-297. Botham S, Isaacs D, Henederson-Smart D. Incidence of apnoea and bradycardia in preterm infants following DTPw and Hib immunization: a prospective study. J Paediatr Child Health 1997;Oct;33(5):418 421. Stajich G, Lopez G, Harry S, Sexson W. Iatrogenic exposure to mercury after hepatitis B vaccination in preterm infants. J Pediatr 2000;136;679-681.

Web links: • • •

Australian Immunisation Handbook 7th Edition Childhood Immunization Support Program The homepage of the Childhood Immunization Support Program. A very good site containing important information for health care providers and parents.

79

30. INCUBATOR TO COT TRANSFER A. B. C. D.

Introduction The premature infant and temperature maintenance Nursing Assessment References

A. Introduction: Evaluating when is the right time to transfer a preterm infant from a closed incubator into an open cot is an essential skill for staff in the Special Care Nursery (SCN). Incubators are designed to minimise heat loss and provide a thermo-neutral environment requiring minimal metabolic effort by the baby to maintain a normal temperature. Incubators are not required for the entire length of the baby's SCN stay. Recognising when an infant is capable of maintaining it's temperature in an open cot is an important step in planning for discharge.

B. The premature infant and temperature maintenance: Achieving temperature stability is important in optimising body growth and development in the premature infant. Both premature and low birth weight infants have: - sparse brown fat available for heat production - small liver with limited glycogen stores for energy and heat production - large surface area to body mass posing a huge potential for heat loss - immature response of the central nervous system to cold stress Cold stress can lead to: - feeding intolerance - respiratory and metabolic acidosis - hypoglycaemia - hypoxia

C. Nursing Assessment: - infant weight: • •

-

-

-

infants weighing 1500 grams or more are candidates for extremely preterm infants consistent weight gain is an additional indicator incubator settings: • the incubator should be in manual mode • stable body temperature (36.5 - 37.0•C per axilla) with the incubator set in the lower range of the neutral thermal range (NTE) physiologically stable: • the infant must be systemically well and physiologically stable feeding: • the infant should be tolerating feeds monitoring: • on transfer from incubator to open cot check axillary temperature: ƒ hourly for 4 hours ƒ then 3-6 hourly before feeds parent education

The ambient room temperature in most nurseries is frequently slighter warmer than the home and will influence the amount of clothing and blankets the baby requires on transfer to an open cot compared to at home. Perhaps the most important role is to educate the parents about actions to reduce the risk of SIDS including: - putting the baby's feet to the foot of the cot - placing the baby on his/her back to sleep - prevention of overheating - maintaining a non-smoking environment

D. References: • • • •

Open and Closed Care, Ducker. T and Todd. R, Journal of Neonatal Nursing Vol 6 No 6, 2000. Transition from incubator to waterbed: a care study approach, Harvey. M, Journal of Neonatal Nursing Vol 6 No 6, 2000, p 185 - 188. Kenner. C, Rockwern Amlung. S and Applewhite Flandemeyer. A (1998), Protocols in Neonatal Nursing, W.B Saunders Company Philadelphia. Merenstein. G and Gardner. S (1998), Handbook of Neonatal Intensive Care 4th ed., Mosby St Louis.

80

31. INFANT OF THE CHEMICALLY DEPENDENT WOMAN A. B. C. D. E. F. G. H. I. J.

Problems Encountered By Drug-Dependent Pregnant Women Prenatal And Perinatal Management Postnatal Management Morphine Therapy Non-Opioid Withdrawal Phenobarbitone Therapy Immunisation Breast Feeding Discharge Management Guidelines For Neonatal Abstinence Syndrome Scoring

A. Problems Encountered By Drug-Dependent Pregnant Women: - obstetric - prematurity, growth restriction, fetal demise - medical - asthma, epilepsy, liver disease, valvular heart disease, blood-borne virus infection, nutritional - neonatal - prematurity, growth restriction, neonatal withdrawal, sudden infant death - psychiatric, social, legal, domestic and financial problems The care of an infant born to such a woman needs to be holistic and multidisciplinary.

B. Prenatal And Perinatal Management: - no increase in fetal abnormalities in narcotic users - methadone substitution for heroin use in pregnancy results in: • • •

improved foetal growth improved survival less risk of prematurity

Methadone stabilisation is recommended rather than dose reduction in pregnancy. Withdrawal from narcotics should be avoided due to the risks of miscarriage in the first trimester and premature labour in the third trimester, as well as fetal distress and death in-utero. A majority of women still use some heroin in pregnancy despite methadone treatment. Induction of labour frequently occurs at or less than due date due to the high-risk nature of these pregnancies. Avoid naloxone administration to the newborn baby with respiratory depression — naloxone can precipitate instantaneous and dramatic narcotic withdrawal. If this occurs, the infant should commence morphine therapy as below.

C. Postnatal Management: •

• • •

• • •

Normal rooming-in is appropriate unless other medical problems exist. However, the practice of mother and baby sleeping in the same bed should be discouraged as a woman on narcotic medication sometimes sleeps more deeply and is more difficult to rouse. This may result in her not being alert to her baby’s needs at that time, and has been associated with babies being accidentally asphyxiated. The Paediatric medical team should be involved in the day to day care of these infants. If mother is known to be heroin dependent, or on methadone treatment, then the neonate should be observed for evidence of the Neonatal Abstinence Syndrome (NAS). Neonatal abstinence syndrome is scored using an NAS score chart (a modified Finnegan Scoring System). Infants born to narcotic dependent women are evaluated for signs of withdrawal by mean NAS scoring two hours after birth or sooner if signs of withdrawal are evident, and subsequently at 4 hourly intervals. The scoring should be performed to 1 hour after baby the baby has been fed. The NAS score chart lists 21 signs most commonly seen in the passively narcotic addicted neonate. Each sign and its associated degree of severity are assigned a score. Higher scores accompany those signs found in babies with more severe abstinence that are at an increased risk of morbidity. The total abstinence score is determined by summation of scores assigned to each sign observed throughout the entire scoring interval. The baby’s mother should assist with the scoring and discuss each sign as it is assessed - it is usually the mother who has been with the baby during the scoring interval. Further, it appears to be important in the mother’s acceptance of her baby’s condition that she be actively involved in the scoring process. Due to heroin’s short half life, withdrawal often manifests in the first one or two days of life, whereas significant withdrawal from methadone may take up to 7 days to become apparent. Hence, mothers and their babies should be routinely observed as in-patients for at least seven days before being discharged. Neonates with an abstinence score averaging 8 or more for three consecutive scores should be transferred to the Special Care Nursery for evaluation for morphine therapy. If there are inconsistencies in the scores, the baby may be observed for a period of time to ensure morphine therapy is truly indicated.

81

D. Morphine Therapy: All doses for entire period of withdrawal management are calculated on birth weight and not current weight.

Score 8-10

Dosage (oral) 0.5 mg/kg/day in 4 hrly doses

if score increases for 2 scores >10

0.7 mg/kg/day in 4 hrly doses

if score further increases for 2 scores and is >13

0.9 mg/kg/day in 4 hrly doses

Once abstinence has been controlled (three consecutive scores less than 8) the following should be implemented: - maintain control for 72 hours - initiate the detoxification process by decreasing the total daily dose by 10% every 48-72 hours - when dosage levels reach 0.2mg/kg/day - maintain this dose for 72 hours - change from 4 hourly to 6 hourly dosage regime (same dose) for 72 hours prior to ceasing all medication - when oral morphine treatment is discontinued, NAS scoring should continue for a further 72 hours Supportive therapy (using a pacifier, swaddling, close wrapping, small frequent feeds, providing close skin contact) is an important adjunct to medical therapy. If an infant is vomiting in association with morphine dosing, ensure that the infant is not being overfed and that the infant is being appropriately postured during and after feeding. Give the morphine before the feed. If baby has a large vomit after being given morphine: - if vomits within 10 minutes of dose, re-dose - if vomits after 10 minutes of dose, give dose - if baby vomits after feed, do not give further morphine (always err on side of caution)

E. Non-Opioid Withdrawal: If the mother does not use opioid drugs but uses other central nervous system depressants (eg benzodiazepines, barbiturates, and alcohol), phenobarbitone is the drug of choice for management of significant withdrawal. Where a mother is on a combination of methadone and benzodiazepines and the infant is not settling with morphine therapy alone, phenobarbitone therapy may be a better option for management of withdrawal symptoms.

F. Phenobarbitone Therapy: Score 8-10

Dosage 15 mg/kg IMI stat, then 6 mg/kg/day in 2 divided doses orally

if score increases for 2 scores >10

8 mg/kg/day in 2 divided doses orally

if score further increases for 2 scores and is >13

Phenobarbitone 10 mg/kg/day in 2 divided doses orally

After scores fall below treatment level for 48 hours the dose should be reduced by 2mg per dose every 4th day or longer depending on scores.

G. Immunisation: The infant should receive Hepatitis B immunoglobulin (100 units IMI) if the mother is HBsAg positive. Hepatitis B immunisation is now universal. This regime is 90% protective.

82

H. Breastfeeding: Breast-feeding is generally not discouraged. The risk of transmission of Hepatitis C via breast milk is very low. Small amounts of methadone are transmitted to the baby in breast milk, but not usually in sufficient quantities to affect the baby clinically or to prevent a woman from breast-feeding. Women taking drugs other than narcotics may need individual advice regarding breast feeding as there may be potential for effects in the breast-fed newborn, although usually the benefits of breast milk outweigh the risks.

I. Discharge Management: An infant can be considered for discharge when either: - a 7 day postnatal observation period is completed and there are no signs of continuing significant withdrawal. There is a significant risk of unsupervised withdrawal occurring at home if infants are discharged earlier than 7 days, particularly if mother is on methadone - the infant requiring medical therapy for withdrawal has been off all medication for at least 72 hours (this may not apply to phenobarbitone) - any child protection issues and significant parental issues (eg suitable accommodation) have been appropriately addressed - the infant should have early medical followup (within 2 weeks of discharge) and have early and regular review by domiciliary/maternal and child health nurses

J. Guidelines For Neonatal Abstinence Syndrome Scoring: Neonatal abstinence syndrome scoring was designed for term babies fed four hourly. Scoring should be performed to 1 hour after a feed, before the baby falls to sleep. See below for modifications necessary for premature babies * SIGNS:

High pitched cry

Score 2 if high-pitched at its peak, 3 if high-pitched throughout

Tremors

This is a scale of increasing severity and a baby should only receive one score from the four levels of severity. Undisturbed refers to the baby being asleep or at rest in the cot.

Increased muscle tone

Score if the baby has generalised muscle tone greater than the upper limit of normal.

Excoriation

Score only when excoriations first appear, increase or appear in a new area.

Yawning and sneezing

Score if occurs more than 3 to 4 times in 30 minutes.

Nasal flaring/respiratory rate

Score only if present without other evidence of lung or airways disease.

Excessive sucking

Score if more than that of an average hungry baby.

Poor feeding

Score if baby is very slow to feed or takes inadequate amounts.

Regurgitation

Score only if occurring more frequently than would be expected in a newborn baby.

* Modification for prematurity - mainly necessary in the sections on sleeping and feeding. A baby on 3 hourly feeds can sleep at most 2 hours. Scoring should thus be 1 if a baby sleeps less than 2 hours, 2 if sleeps less than 1 hour, and 3 if it does not sleep between feeds. Many premature babies require tube feeding. Babies should not be scored for poor feeding if tube feeding is expected at their gestation.

83

32. INFANT OF THE DIABETIC MOTHER (IDM) A. B. C. D. E. F. G. H.

Summary Introduction Fetal effects of maternal hyperglycaemia Perinatal complications of diabetes in pregnancy Neonatal complications of diabetes in pregnancy Neonatal management Long Term Complications Reference

A. Summary: -

complications in IDMs relate to hyperinsulinism, macrosomia and in utero hypoxia IDMs (especially those that are macrosomic or growth restricted) are at increased risk of hypoglycaemia IDMs should be screened for hypoglycaemia and be fed early and frequently IDMs are at increased risk of HMD and PPHN - watch for respiratory distress and keep well oxygenated normosomic infants of diet controlled gestational diabetic mothers often require minimal intervention

B. Introduction: Approximately 6% of pregnancies are complicated by maternal diabetes mellitus (80% of which are gestational). Maternal hyperglycaemia can result in fetal hyperglycaemia and then secondary fetal hyperinsulinism. Insulin is the main 'growth hormone' of the fetus and therefore infants of diabetic mothers (IDM) are often macrosomic (> 4,000 g) or large for gestational age (>90th percentile). The problems associated with being IDM relate to the effects of hyperinsulinism and/or macrosomia. The macrosomia is due to excessive fat deposition, visceral organ hypertrophy (except brain and kidney) and acceleration of body mass accretion. Macrosomic IDMs have higher rates of neonatal morbidity and mortality.

C. Fetal effects of maternal hyperglycaemia: -

poor glycaemic control during embryogenesis can result in a 4 to 8 fold increase in congenital malformations, including: • cardiac defects • CNS defects (including anencephaly and spina bifida) • genitourinary and limb defects

however, these are not seen with an increase frequency in infants of diabetic fathers, or mothers where gestational diabetes develops after the first trimester

-

macrosomia leading to increased risk of: • shoulder dystocia • clavicular fracture • facial nerve palsy • brachial plexus injury • facial nerve injury • cephalhaematoma • asphyxia • perinatal and neonatal mortality

However, not all cases of macrosomia can be prevented even with rigid glycaemic control during the 2nd and 3rd trimesters. In fact most macrosomic infants are born to mothers without diabetes (risk factors include morbid maternal obesity, excessive weight gain during pregnancy, multiparity, postmaturity and a previous macrosomic infant).

-

episodic fetal hypoxia stimulated by episodic maternal hyperglycaemia leads to an outpouring of adrenal catecholamines, which can cause: • hypertension • cardiac hypertrophy • stimulation of erythropoietin, leading to polycythaemia and therefore • +/- hyperviscosity • increase risk of thrombosis • hyperbilirubinaemia (increased red cell mass)

84

D. Perinatal complications of diabetes in pregnancy: -

-

increased perinatal mortality due to: • congenital malformations • extreme prematurity • fetal demise • intrapartum asphyxia • RDS birth injury: • shoulder dystocia • brachial plexus trauma over-representation of IUGR (even if mother does not have pre-existing IDDM with small vessel disease) - seen in 20% of IDMs

E. Neonatal complications of diabetes in pregnancy: -

-

-

polycythaemia and hyperviscosity due to: • increased erythropoiesis secondary to fetal arterial hypoxaemia secondary to hyperinsulinism • shift in blood from placenta to fetus during hypoxia hypoglycaemia: • incidence varies from 25-40% hypocalcaemia (due to functional hypoparathyroidism and hypomagnesaemia): • occurs in approximately 50% of insulin-dependent diabetics • suspect if: ƒ irritability ƒ coarse tremours ƒ jitters ƒ tongue thrusting ƒ twitches ƒ apnoea ƒ seizures hypomagnesaemia (due to maternal hypomagnesaemia/increased renal losses with glycosuria) hyperbilirubinaemia due to: • polycythaemia (increased RBC mass) • increased extravascular haemolysis (bruising, cephalhaematoma) • delayed oral feeding (increased enterohepatic circulation) • liver immaturity hypertrophic and congestive cardiomyopathy: • usually asymptomatic • usually resolves by 8-12 weeks hyaline membrane disease due to: • delayed fetal lung maturation (insulin impedes glucocorticoid effect) • prematurity • increased incidence of Caesarean section in near term deliveries/complicating 'wet lung syndrome'

F. Neonatal management: -

screening for and treatment of hypoglycaemia early, frequent oral feeding (preferably breast milk) glucose infusion (4-6 mg/kg/minute = 60-80 mls/kg/day 10% dextrose) judicious use of glucagon. This can result in rebound neonatal hyperglycaemia and perpetuation of hyperinsulinism. However, it can be very useful in the interim where IV access is not readily achievable and the 'pushing' of feeds is inappropriate avoid wide swings in infant blood glucose (may perpetuate hyperinsulinism and delay gluconeogenesis): • the use of 'mini' boluses of glucose for hypoglycaemia (e.g. 2 mls/kg 10% dextrose) • avoid of high calorie formula measurement of serum calcium and magnesium adequate oxygenation if baby has HMD (at increased risk of PPHN)

85

G. Long Term Complications: - obesity - up to 50% - risk of subsequent overt diabetes: • • • • •

-

type 1 - father diabetic - 6.1% type 1 - mother diabetic - 1.3% type 2 - mother diabetic - 50% GDM - father diabetic - 7% GDM - mother diabetic - 35% adverse neurodevelopment in 4% of cases (may relate to maternal ketosis)

H. References: • • • • •

Reece EA, Homko CJ. Infant of the diabetic mother. Seminars in Perinatology. 1994;18:459-69 Suevo DM. The infant of the diabetic mother. Neonatal Network. 1997;16:25-33 Tyrala EE. The infant of the diabetic mother. Obstetrics and Gynaecology Clinics of North America. 1996;23:221-41 Cordero L, London MB. Infant of the diabetic mother. Clinics in Perinatology. 1993;20:635-48 Taeusch HW, Ballard RA (Eds). Avery's Diseases of the Newborn 7th Ed. W.B. Saunders Company, Philadelphia. 1998

33. INGUINAL HERNIA AND HYDROCELE A. B. C. D. E.

Summary Introduction Differential Diagnosis Management References

A. Summary: - an irreducible or strangulated hernia requires urgent surgical referral - hydroceles regress spontaneously without need for follow up B. Introduction: The testis descends into the scrotum in the 28th week in utero through a diverticulum of the peritoneum, the processus vaginalis. Failure of obliteration of the processus vaginalis leads to inguinal hernias, hydroceles and encysted hydroceles of the cord. An inguinal hernia is a peritoneal pouch that extends through the inguinal canal sometimes as far as the scrotum. Bowel can pass into it. An inguinal hernia usually presents as an inguinal swelling that is often intermittent so may not be noticed until the baby cries or strains. All inguinal hernias require prompt surgical referral once diagnosed because small bowel can easily become trapped in the hernia compromising the bowel's blood supply and causing bowel obstruction (strangulation). Symptoms of strangulation include inability to squeeze the hernia back (irreducible), excessive crying and later vomiting, abdominal distension and constipation. Inguinal hernias are more common in premature babies. They can occasionally occur in females (and are more common in preterm than term females).

C. Differential Diagnosis: - hydrocoele:

-

This is common. It is a painless fluid filled sack around the testis present from birth. It may not be possible to feel the testis separate from the hydrocele if the hydrocele is tense. Parents should be reassured that the fluid does not harm the testis and that it will usually resolve within a year. No follow up is required if both testes are felt and a hernia is not suspected. A hydrocele must have all three of the following features otherwise a hernia should be suspected • a narrow spermatic cord felt above the swelling • it transilluminates • it does not empty on squeezing. undescended testis or retractile testis encysted hydrocele of the cord A discreet painless swelling within the spermatic cord, above the testis and below the external inguinal ring. It usually resolves spontaneously.

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D. Management: A reducible inguinal hernia requires an early surgical consult and will usually be repaired on the next convenient surgical list. An irreducible or strangulated hernia requires urgent surgical referral. Premature infants should have their hernia repair prior to discharge. Post-operative apnoea is less common after 42 corrected weeks of gestation.

E. References: • • •

Hutson, J.M., Woodward, A.A., and Beaseley, S.W. (editors). Jones' Clinical Paediatric Surgery. 5th edition. Blackwell Science Pty Ltd. 1999. Smart, J. (editor). Paediatric Handbook. 6th edition. Blackwell Science Pty Ltd. 2000. Balfour-Lynn, I.M. and Valman, H.B.V. Practical Management of the Newborn. 5th edition. Blackwell Science Pty Ltd. 1993.

34. INTRAMUSCULAR (IM) INJECTION A. B. C. D. E.

Introduction Equipment Procedure Pratice points Reference

A. Introduction: The anterolateral thigh is the preferred site for IM injection in infants under 12 months of age. Medications are injected into the bulkiest part of the vastus lateralis thigh muscle, which is the junction of the upper and middle thirds of this muscle. Nursing and medical staff must be familiar with the principles of the administration of medications to an infant. These principles include: - observation of universal precautions - aseptic techniques and correct drug/dose/time/route/patient practices

B. Equipment: -

IM medication ampoule Large bore needle for withdrawing medication from ampoule 1 ml or 2 ml syringe 23 gauge 25 mm needle or 25 gauge 16 mm needle for preterm babies 2 months or younger Alcohol swab Cotton wool swab Gloves for universal precautions

C. Procedure: • • • • • • • • •

There must be a written medication order on the medication chart. Check the correct drug/dose/time/route/infant. Draw the medication up into the syringe using the large bore needle. Change to the 23 gauge 25 mm needle or 25 gauge 16 mm needle. A second staff member to help position the infant on his/her back on a table or bed may be required. Undo the infant’s nappy to locate the junction of the upper and middle thirds of the vastus lateralis thigh muscle. Clean the skin with an alcohol swab and ensure that the site is dry prior to the IM injection The clinician performing the injection places their forearm across the infant’s pelvis and secures the thigh between their thumb and forefinger. Bunch up the thigh muscle to increase the muscle mass.

Administer the IM injection at a 45-60 angle to the skin. The needle must be angled toward the knee. At this angle, the needle can be safely inserted to a depth of between 16-23 mm skin-to-needle-tip depth. Inserting the needle at this angle results in less tissue resistance as the needle penetrates the muscle. The following figures of the thigh show the recommended injection site.

87

Figure 1: Diagram of the muscles of the thigh showing the recommended injection site. (NHMRC, 2000, p. 10)

Figure 2: Diagramiatic cross section of the thigh showing recommended injection site. (NHMRC, 2000, p. 10) Withdraw the plunger to ensure that the medication does not go directly into a blood vessel. Slowly inject the medication for even distribution and to minimise the infant's discomfort. Remove the needle. Check the injection site for bleeding and apply cotton wool ball if necessary. Observe the site for local inflammation. Dispose of the needles and syringe into a labeled puncture proof container to prevent needle stick injury & reuse. Document the administration of the IM injection on the medication chart and/or child health record (where appropriate).

D. Practice Points: Alcohol and other disinfecting agents must be allowed to evaporate before injection of medication. Never give an IM injection in the buttocks. Using the vastus lateralis muscle avoids the risk of sciatic nerve damage from gluteal injection. Also the vastus lateralis muscle has a larger muscle mass than the gluteal region and therefore has reduced risk of severe local reactions. The deltoid in infants is not sufficiently bulky to absorb IM medications adequately. The vastus lateralis muscle avoids the thicker layer of subcutaneous fat on the anterior thigh. It is important that infants do not move during the IM injection. However excessive restraint can increase the infant’s fear and can result in increased muscle tension The infant can be held in the ‘cuddle’ or semi-recumbent position on the lap of the parent/caregiver/health professional. The volume of the IM injection should not be more than 1ml. When two IM injections are being administered, give one medication into the right thigh and the other into the left thigh.

E. References: •

NHMRC (2000). The Australian Immunisation Handbook (7th ed). Canberra: Australian Government Publishing Services.

88

35. INTRAOSSEOUS NEEDLE INSERTION A. B. C. D. E. F. G. H.

Introduction Sites Equipment Required Procedure Absorption Contra-indications Complications Further Information

A. Introduction: During the first week of life the umbilical vein is a convenient route for obtaining vascular access during emergencies. The intraosseous (IO) route provides an option for establishing rapid venous access in an emergency after that time. The bone marrow cavity has an extensive virtually non-collapsible vascular network directly communicating with the systemic circulation. Medications or fluids given by the IO route diffuse a few centimetres through the medullary cavity then enter the venous circulation.

B. Sites:

The proximal tibia is the preferred site. The entry point is a few centimetres below the tibial tuberosity at the centre of the flat antero-medial surface. The needle is directed caudal away from the upper tibial epiphysis in the line of the shaft.

The distal antero-medial surface of the tibia is an alternate site which can be used in children of all ages. The distal femur and sternum should not be used.

C. Equipment Required: - sterile gloves and gown - basic dressing pack - antiseptic to prepare the skin - rigid needle with an inner stylet (for patients < 18 months an 18 -20 lumbar puncture needle can be used) - syringe with NaCl 0.9% flush - routine IV line tubing set-up and tape 89

D. Procedure: -

observe universal precautions immobilize the extremity prepare the site with antiseptic consider need to use local anaesthetic( 0.5-1 mL 1% lignocaine ) if time permits insert the needle

The needle handle is held in the palm of the hand while the thumb and forefinger grip the shaft about a centimetre from the point to stabilize the needle. Firm pressure is applied while using a screwing or rotary action until the bone cortex is traversed. At approximately 1cm or less, below the skin surface, a distinct loss of resistance on entry of the bone marrow is felt. Three factors should be noted: • a distinctive pop with insertion, or a give or release of resistance is felt • the needle flushes without significant subcutaneous infiltration and bone marrow is easily aspirated • the needle stands without support - unscrew and remove the stylet - attempt bone marrow aspiration. (bone marrow can be used as a substitute for venous blood for estimation of PCO2, pH, Hb, electrolytes, urea, creatinine, proteins etc) - flush the needle with 5-10 mL of normal saline to decrease the cellularity of the surrounding marrow, aiding subsequent infusions - attach IV tubing and commence the infusion of medications or fluids by pump

E. Absorption: Recommended intravenous rates for drugs and fluids can be administered via the I.O. route and reach the central circulation in equivalent times. Strong alkaline and hypertonic solutions should be diluted before use.

F. Contra-indications: Absolute: - osteogenesis imperfecta - osteopetrosis Relative: - limb is traumatised - fracture - infection

G. Complications: -

extravasation of fluid, drugs or air into skin or periosteum. A larger hole is created if a rocking motion is used during insertion of the needle. It may also occur if there has been a previous I.O. infusion in the same bone sub-periosteal infusion may occur when the needle fails to enter the bone marrow through and through puncture occurs if the needle is advanced too far blockage of the needle may occur if no inner stylet is used infection -cellulitis, abscess formation, skin necrosis and osteomyelitis tibial fracture fat and bone marrow microemboli

H. Further Information: •

Insertion of Cook Intraosseous needle/Emergency intraosseous infusion. A video produced and distributed by Cook Australia, Running time 35 minutes.

90

36. INTRAVENOUS ELECTROLYTE CORRECTION A. B. C. D. E. F. G.

Introduction Hypocalcaemia Hyponatraemia Hypokalaemia Hypomagnesaemia Metabolic acidosis (Sodium Bicarbonate) Other Reading

A. Introduction: -

-

apart from acid-base balance, electrolyte levels immediately after birth reflect maternal electrolyte status and are therefore only useful as a baseline. The exception might be a mother who has been water overloaded during labour with the result of both her and the fetus becoming hyponatraemic. In some cases the infant may be symptomatic (seizures) and require treatment an unexpectedly abnormal result in a well, asymptomatic infant is most likely to be due to sampling or laboratory error. In this situation, it always advisable to repeat the test before embarking upon a potentially risky correction as with all interventions, it is wise to consider the risks vs benefits of correcting any electrolyte disturbance refer to the section on normal laboratory values for definitions these recommendations are a guide only

B. Hypocalcaemia: -

-

1.5 mL x wt(kg) of 10% calcium gluconate in maintenance intravenous fluid over 4 hours 1 mL of 10% calcium gluconate contains 0.2 mmol calcium only indicated if the baby is symptomatic: • hypotension requiring inotropic support • PPHN • unexplained jitteriness • seizures side effects include: • reduced IV half life • risk of IV burn consider hypomagnesaemia if recalcitrant hypocalcaemia

C. Hyponatraemia: -

0.18 x deficit (from lower limit of normal for age) mL x wt(kg) of 20% sodium chloride over 6 hours (12 hours if <120 mmol/L as rapid or over correction can cause neurological complications) 1 mL of 20% sodium chloride contains 3.42 mmol sodium consider cause of hyponatraemia: • urinary losses - check urinary sodium • GIT losses • inadequate intake of sodium • excessive intake of water • SIADH (rare in very premature infants)

D. Hypokalaemia: -

1.2 mls x wt(kg) of 15% potassium chloride over 6 hours do not exceed 0.4 mmol/kg/hr 1 ml of 15% potassium chloride contains 2 mmol potassium consider cause of hypokalaemia: • resolving/recent metabolic acidosis • diuretics, particularly frusemide N.B. true hypokalaemia may be missed if haemolysis occurs during sampling. Capillary specimens are usually haemoliysed to a greater or lesser degree.

91

E. Hypomagnesaemia: -

-

0.2 mls x wt(kg) 50% MgSO4, diluted to 20% IV slowly (may be arrhythmogenic). IMI administration, although painful, is an alternative if there is no intravenous cannula in situ do not exceed 0.75 mls/minute 1 ml of 50% magnesium sulphate contains 2 mmol magnesium consider with: • recalcitrant hypocalcaemia • PPHN • seizures may cause hypotension if given too quickly

F. Metabolic acidosis (Sodium Bicarbonate): -

-

-

0.25 x base deficit x wt(kg) of 8.4% NaHCO3, diluted 1:1 with H2O or 0.9% saline, given slowly over 30 60 minutes 1 ml 8.4% NaHCO3 contains 1 mmol bicarbonate do not give with 10% dextrose as • increases osmolality and risk of IVH • unnecessary • disturbs glucose homeostasis consider if B.E. < -8.0, although pointless if pCO2 not controlled consider and treat underlying cause: • hypoxia • hypotension • poor perfusion • patent ductus arteriosus • sepsis if chronic acidosis, consider renal tubular cause and check urine pH at time of acidosis (if acidotic, should be <=5)

G. Other Reading: • • • • •

Walter JH. Metabolic acidosis in newborn infants. Arch Dis Child 1992;67:767-9 Modi N. Sodium intake and preterm babies. Arch Dis Child 1993;69:87-91 Herin P, Zetterstrom. Sodium, potassium and chloride needs in low-birth-weight infants. Acta Paediatr 1994;Suppl 405:43-8 Trachtam H. Sodium and water homeostasis. Pediatr Clin North Am 1995;42:1343-43 Taeusch HW, Ballard RA (Eds). Avery's Diseases of the Newborn 7th Ed. W.B. Saunders Company, Philadelphia. 1998

37. INTRAVENOUS INFUSION FOR SCN ADMISSIONS A. B. C. D. E.

Introduction Fluid Infused Investigations Introducing enteral feeding Inputs ( while nil po)

A. Introduction: These recommendations are to guide the care of infants admitted to SCN (NOT NICU) who cannot commence enteral feeds shortly after birth. Such infants will usually have problems of mild/moderate RDS and/or prematurity (>30weeks gestation). Infants awaiting transfer to a higher dependency unit or with specialised problems (eg bowel obstruction with vomiting) should have fluid management as indicated for their specific condition or as discussed with an appropriate specialist. The goal of treatment is to maintain hydration and avoid biochemical disturbances, particularly hypoglycaemia and hyponatraemia.

92

B. Fluid Infused: Fluid Volume

Fluid Infused

ml/hr

ml/kg/d

0-24hrs

Bwt x 2.5

60

10% Dextrose

25-48hrs

Bwt x 2.5

60

10% Dextrose

49-72hrs

Bwt x 3

72

10% Dextrose + NaCl + KCl*

>72hrs

Bwt x 4

96

10% Dextrose + NaCl + KCl*

* Ordered as 10% Dextrose 500 ml & 6.5 mL 20% NaC1 &10 mL 7.5% KCl (giving 22 mmol NaCl and 10 mmol KCl per 500mL)

C. Investigations: 0-24hrs

Check BSL: If<2.6mmol/l refer to management of hypoglycaemia

25-48hrs

Monitor serum Na, K

49-72hrs

Check urine output adequate (>1mL/kg/hr) before adding electrolytes

73-96hrs

Check Na, K if still nil po

>96hrs

Consider transfer to a level 3 centre for Parenteral Nutrition if still nil by mouth

D. Introducing enteral feeding: Consider change in clinical condition e.g. resolution of respiratory distress, conscious state. - For term infants Halve IV infusion rate. Offer sucking feeds on demand or at least 4th hourly. After two or three sucked feeds IV access may be ‘bunged off’ and feeding performance assessed. If intravenous access is not required as a route for medications the cannula should be removed as soon as possible. While the ‘bunged off’ line is in place flush short extension tubing every 6 hours with 0.5mL 0.9% Sodium Chloride (ordered on the infant’s medication sheet). Check at least 6 hourly for signs of phlebitis/extravasation and integrity of cannula and extension set.

-

For infants <36 wks gestation:

Start at 30 mL/kg/d; reduce IV infusion rate to maintain desired total infusion. Increase by enteral intake by 30 to 40 mL/kg/d. IV infusion can usually cease when >90 mL/kg/d enteral intake achieved. Thereafter enteral intake is gradually increased to 150 mL/kg/d total.

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E. Inputs ( while nil po): Volume

Glucose

Na

K

Energy

mL/kg/d

mg/kg/min

mmol/kg/d

mmol/kg/d

KJ/kg/d

KCal/kg/d

0-24hrs

60

4

-

-

100

24

25-48hrs

60

4

-

-

100

24

49-72hrs

72

5

3

1.5

125

30

>72hrs

96

6.6

4

2

160

38

38. INTUBATION A. B. C. D. E. F. G. H. I.

Summary Introduction Equipment Monitoring Endotracheal Tube Size and Length Procedure Confirmation of tube position Areas of Uncertainty in Clinical Practice References

A. Summary: -

in an emergency oral intubation is the route of choice if unfamiliar with technique of intubation use bag and mask until adequate help arrives. The majority of infants can be managed with bag and mask ventilation muscle relaxants are contraindicated in situations known to be associated with difficult intubation (e.g. Pierre Robin sequence) or when the operator is inexperienced with these medications the commonest reason for the clinical condition not to improve after intubation is because either the oesophagus or the right main bronchus has been intubated

B. Introduction: Endotracheal (ET) intubation is an important procedure in the care of the newborn. C. Equipment: -

laryngoscope -Handle: Penlon miniature with hook-on fitting blades: 00, 0 (Premature), 1 (Neonatal) introducer (in sterile package) –for oral intubation, it must be inserted to 1cm less than the length of the ET tube magills forceps –for use during nasotracheal intubation endotracheal tubes: Portex Paediatric, Sizes 2.5, 3.0 and 3.5mm connectors to fit between ET tubes and ventilation bag and circuit, Neopuff or mechanical ventilator tapes for securing ET tubes - Sleek "trousers", Leukoplast or Elastoplast, tie skin prep swabs cotton buds Tinc. Benzoin Co. (optional)

D. Monitoring: During an acute cardiorespiratory arrest or in the delivery room monitoring may not be achievable. In controlled situations, before commencing intubation, place infant under radiant warmer, obtain IV access, attach cardiorespiratory and oxygen saturation monitors and record full baseline observations.

94

E. Endotracheal Tube Size and Length: Most babies <1250 grams (<32 weeks) will need a 2.5 mm ID (internal diameter) ET tube. 1250 - 3000 grams (3238 weeks) a 3.0 ID tube and >3000 grams (>38weeks) a 3.5 ID tube.

Baby Weight (kg)

Tube Size (mm)

Oral Tube Length at Lip (cm)

Nasal Tube Length at Nose (cm)

Suction Tube Size (Fr)

<1.0

2.5

5.5

7.0

6

1.0

2.5-3.0

6.0

7.5

6

2.0

3.0

7.0

9.0

6

3.0

3.0

8.5

10.5

6

3.5

3.0-3.5

9.0

11.0

8

4.0

3.5

9.0

11.0

8

An alternative is to assess ET tube length by the rule of six. Oral tube length(cm) =: 6 + wt (kg) Nasal tube length(cm) = 6 + (1.5 x wt) The formulas are general guides only and appropriate position must always be confirmed clinically and radiologically. The oral tube formula may produce a low lying tube while the nasal tube formula may result in a high tube.

F. Procedure: • • • • • • • •

•

Observe universal precautions. Maintain sterility of equipment until use. Use a new ET tube for each intubation attempt. Aspirate stomach contents prior to procedure if the infant has been fed recently. Place infant’s head in the slightly extended ‘sniffing’ position but remember that one of the commonest errors of endotacheal intubation is over-extension of the upper airway. Pass laryngoscope blade gently along the side of the mouth and gently pull tongue and epiglottis forward by lifting the blade. If the vocal cords and epiglottis do not come into view pull the laryngscope back gradually until they are seen to avoid intubation of the oesophagus. Application of cricoid pressure may be helpful. If the infant remains bradycardic for more than 30 seconds during the procedure and intubation is not near complete remove tube and ventilate the infant by bag and mask until HR, colour and oxygen saturation are within normal limits. Following insertion of the ET tube, place a cotton tie securely (but not tightly) around the tube. After drying the face, apply Tinc. Benzoin Co, allow it to dry before applying tapes. adhere the unsplit section of one Sleek "trouser" to the cheek and one tab above the upper lip. Wrap the other tab in a spiral around the ET tube

take the second Sleek "trouser" and adhere the unsplit section to the cheek. Place one tab below the lower lip and wrap the other tab in a spiral around the ET tube

95

G. Confirmation of tube position: The ET should be passed so that the tip lies approximately midway between the vocal cords and the carina. Tube position can be confirmed by:

-

ensuring the ET tube tip is no more than between 2.5 to 3.0cm beyond the vocal cords (to avoid intubation of the right main bronchus) observing symmetrical chest-wall motion hearing equal air entry on both sides of chest and not over stomach (may be an unreliable sign in tiny infants) seeing moisture in the ET tube during exhalation improvement of clinical condition chest x-ray (ET tube tip is seen at the level of T2-T3)

H. Areas of Uncertainty in Clinical Practice: Oral versus Nasal Intubation: The route chosen will depend on the training and skill of the operator since both routes are safe and effective ways to deliver assisted ventilation. In an emergency oral intubation should be performed. Premedication/Sedation: Intubation causes physiological destabilisation and effects consistent with those seen in older individuals while experiencing pain. There are several reports that such changes can be reduced by premedication with a variety of agents. The only trials assessing safety have been performed in the NICU or by NICU transport personnel.

-

-

-

the following suggestions are based on guidelines (using readily available drugs) that have been successfully used by NETS Victoria for some years at delivery or in "arrest" situations intubation without sedation is warranted in controlled situations consider premedication – the decision will depend on the experience and training of the operator. Since intubation is made more difficult by an active patient, premedication is particularly relevant for mature infants: sedation with paralysis (preferred option) use atropine 10 – 30 mcg/kg IV followed by morphine sulphate 0.1 – 0.2 mg/kg IV and after 3-5 minutes suxamethonium 1.5 – 3 mg/kg IV; as neuromuscular paralysis develops commence hand ventilation and then intubate. A repeated dose of suxamethonium may be required occasionally and should be drawn up ready for use sedation without paralysis using morphine sulphate 0.15 mg/kg IV and midazolam 0.15 mg/kg IV; it is important to wait at least 3 – 5 minutes for onset of effect. NOTE: Midazolam infusion has not been established as safe for use in very preterm infants. There have been reports of occurrence of dystonic reactions and seizures intubation of very immature infants without premedication may be appropriate at Monash Medical Centre the standard premedication sequence uses for infants < 1000gm sedation with fentanyl 2microgm/kg (IV over 30 seconds) for larger infants, fentanyl 2microgm/kg (IV over 30 seconds) followed by suxamethonium 2mg/kg IV over 10 to 30 seconds. Atropine (10microgm/kg over 1 minute) may be required if repeated doses of suxamethonium are used

A laryngeal mask has been designed as a means of enabling assisted ventilation without actual passage of an ET tube through the vocal cords. This has not been fully evaluated in newborns or established yet as a standard practice.

I. References: • • • •

Premedication for Neonatal Intubation K.J.Barrington, P.J.Byrne Am.J.of Perinatology 15,4,1998, 213-216 Nasal versus oral intubation for mechanical ventilation of newborn infants. Spence K, Barr P. Cochrane Database Syst Rev 2000 Intubating the Newborn, Judy A. Littleford. 1997. 32 minute videotape University of Manitoba, Health Sciences Book Store 140 Brodie Centre, 727 McDermot Ave, Winnipeg, Manitoba, Canada

96

39. Jaundice in the first two weeks of life A. B. C. D. E. F. G.

Introduction Physiological Jaundice Pathological Jaundice Treatment of Jaundice Phototherapy Exchange Transfusion Tables

A. Introduction: - occurs in approximately 50% of newborns (unimportant in most) - a few will become deeply jaundiced requiring investigation and treatment - if inadequately managed, may result in: • •

-

death survival with severe brain damage early detection of jaundice (appears in the sclera with SBR of 35-40 mmol/L) may be difficult in newborns because eyelids often swollen and usually closed jaundice may not be visible in the neonate's skin until the bilirubin concentration exceeds 100-120 mmol/L

Causes:

-

physiological pathological

B. Physiological Jaundice: Develops because of: - increased production - decreased uptake and binding by liver cells - decreased conjugation (most important) - decreased excretion - increased enterohepatic circulation of bilirubin As the name implies, physiological jaundice is common and harmless

C. Pathological Jaundice: Best considered in relation to time from birth.

(1) "Too Early" (< 24 hours of age):

-

-

always pathological usually due to haemolysis, with excessive production of bilirubin babies can be born jaundiced with: • very severe haemolysis • hepatitis (unusual) causes of haemolysis (decreasing order of probability): • ABO incompatibility • RH immunisation • sepsis rarer causes: • other blood group incompatibilities • red cell enzyme defects e.g. G6PD deficiency • red cell membrane defects, e.g., hereditary spherocytosis

If there is substantial elevation of conjugated bilirubin (>15% of the total), consider hepatitis (see later). This may also occur in Rh babies who have had in-utero transfusions and even in some that haven't. Investigation of early pathological jaundice: - total and conjugated serum bilirubin concentration (SBR) - maternal blood group and antibody titres (if Rh negative) - baby's blood group, direct antiglobulin (Coombs') test (detects antibodies on the baby's red cells), and elution test to detect anti-A or anti-B antibodies on baby's red cells (more sensitive than the direct Coomb's test) - full blood examination, looking for evidence of haemolysis, unusually-shaped red cells, or evidence of infection

97

(2) "Too High" (24 hours - 10 days of age): If the serum bilirubin concentration exceeds 200-250 mmol/L, over this time, various causes include: - mild dehydration/insufficient milk supply (breast-feeding jaundice) - haemolysis - continuing causes as discussed under "too early" - breakdown of extravasated blood (e.g. cephalhaematoma) - polycythaemia (increased RBC mass) - infection - a more likely cause over this time - increased enterohepatic circulation (e.g. gut obstruction) •

Infection: If the baby has other signs of infection, as well as excessive jaundice, acute bacterial infection must be excluded. Infections acquired early in pregnancy may cause neonatal hepatitis, but other clinical signs are obvious and a substantial fraction of the jaundice is conjugated (>15%).

•

Breast-milk Jaundice: From as early as the third day of life, the serum bilirubin concentration of breastfed infants is higher than in those who are formula-fed. What it is in breast milk that causes excessive jaundice is not known, but unsaturated fatty acids or a lipase, which inhibits glucuronyl transferase, have been suspected. Because most babies are initially breast-fed, inadequate fluid and calorie intake resulting in haemoconcentration are contributors to jaundice; unfortunately a specific diagnosis is not possible (breast-feeding jaundice).

(3) "Too Long" (> 10 days of age, especially > 2 weeks): The major clue to diagnosis is whether the elevated bilirubin is mostly unconjugated (>85%) or whether the conjugated fraction is substantially increased (>15% of the total). Causes of persistent unconjugated hyperbilirubinaemia: - breast milk jaundice (diagnosis of exclusion, cessation not necessary) - continued poor milk intake - haemolysis - infection (especially UTI) - hypothyroidism •

Hypothyroidism: Persistent jaundice may be the earliest sign of hypothyroidism in the infant. Fortunately, all babies are routinely screened for this disease. However, if other signs suggest hypothyroidism, further investigation is mandatory because appropriate early treatment may prevent profound developmental delay.

•

Haemolysis: When jaundice suddenly reappears after the infant has gone home, severe haemolysis is the usual cause, particularly in infants with G6PD deficiency who are exposed to mothballs (naphthalene). G6PD deficiency occurs most often in Mediterranean, Asian and African ethnic groups, and is more severe in males (being X-linked).

Causes of Persistent Conjugated Hyperbilirubinaemia: A simple test of urine for bile will suggest substantial elevation of conjugated bilirubin. This is rare, and the infant either has hepatitis or biliary atresia and therefore requires extensive investigation. •

Hepatitis: Can be caused by infection (toxoplasmosis, rubella, cytomegalovirus, hepatitis, or syphilis), or by metabolic disorders (e.g., galactosaemia).

•

Biliary Atresia: A very rare disorder in which the bile ducts are absent, causing an obstructive jaundice which is fatal in most cases. These babies usually have pale stools.

D. Treatment of jaundice: Unconjugated bilirubin can be toxic to the brain, and can cause the disease called kernicterus; this is characterised by the death of brain cells and yellow staining, particularly in the grey matter of the brain. The acute signs of bilirubin encephalopathy include:

-

lethargy poor feeding temperature instability hypotonia arching of the head, neck and back (opisthotonos) spasticity seizures

Death may follow. In those who survive, all will have permanent brain damage, including athetoid cerebral palsy, deafness, and mental retardation.

98

The risk of developing kernicterus increases with: - increasing unconjugated bilirubin - concentrations greater than 340 mmol/L are considered unsafe - decreasing gestation - preterm infants may be at risk at lower concentrations of bilirubin, 300 mmol/L or less - asphyxia, acidosis, hypoxia, hypothermia, meningitis, sepsis, and decreased albumin binding (serum albumin concentration too low, or binding interfered with by drugs) Available therapies:

-

treatment of the cause (e.g. infection, hypothyroidism) adequate hydration (via gut, may reduce enterohepatic circulation of bilirubin) phototherapy exchange transfusion

E. Phototherapy: Exposure of jaundiced skin to light photo-isomerises the bilirubin molecule into forms, which can be excreted directly into the bile, without having to be conjugated. The effectiveness of phototherapy increases with: - blue light - intensity of the light (can be checked with a light intensity metre) - the greater the amount of skin exposed - the closer the lights to the baby The major drawback with phototherapy is that its effect is slow (despite a rapid onset of action); phototherapy alone is rarely effective with severe haemolytic causes of jaundice where the bilirubin concentration can rise rapidly.

Indications: Phototherapy should only be used when the bilirubin is approaching a concentration, which would usually lead to an exchange transfusion. In practice, this is 60-70 mmol/L below the exchange value (see Tables).

Complications:

-

overheating water loss diarrhoea ileus (preterm infants) rash (no specific treatment required) retinal damage parental anxiety/separation

Ceasing phototherapy:

-

generally when 'out of range' worthwhile checking SBR day after cessation as may rebound can tolerate higher SBR once sepsis, haemolysis excluded in well term baby

F. Exchange Transfusion: Indications:

-

if infant with Rh-disease not received blood transfusions in utero: • cord blood haemoglobin < 100 g/L • or cord bilirubin > 80 mmol/L • or baby visibly jaundiced within 12 hours of birth

The effects of intrauterine transfusions are unpredictable, but haemolysis is usually less severe because more of the baby's blood is Rh-negative donor blood. - well term infants: • bilirubin >340 mmol/L • and likely to exceed that concentration for any length of time • and due to haemolysis (for non-haemolytic jaundice, see the Tables)

99

-

In preterm or sick infants, lower concentrations of bilirubin may warrant exchange transfusion since exchange transfusions are rarely performed today, especially outside level-III centres, it is advisable that any baby who requires an exchange transfusion be transferred to a level-III centre. It is preferable that the blood is cross-matched prior to transfer so that the baby can be exchanged as soon as possible after arrival

After an exchange transfusion subsequent monitoring of the haemoglobin is necessary because ongoing haemolysis may result in significant anaemia, and the baby may need a top-up simple blood transfusion.

G. Tables: 1. Management of non-pathologic jaundice in healthy term infants: For healthy term babies, phototherapy and exchange transfusion can be provided as recommended in the AAP Guidelines (published in Pediatrics 94:558-565, Oct. 1994).

Age (hrs)

Consider Phototherapy

Phototherapy

Exchange Transfusion if Intensive Phototherapy Fails

Exchange Transfusion and Intensive Phototherapy

SBR (m mol/L)

SBR (m mol/L)

SBR (m mol/L)

SBR (m mol/L)

<24 hours

---

---

---

---

25 - 48 hours

> 200

> 260

> 340

> 430

49 - 72 hours

> 260

> 310

> 430

> 510

> 72 hours

> 290

> 340

> 430

> 510

2. Management of jaundice in preterm infants: Phototherapy:

Age

Wt <1500g <1500g.

Wt 1500 – 2000g

Wt > 2000g

SBR (m mol/L)

SBR (m mol/L)

SBR (m mol/L)

< 24 hours

High risk*: all Others: > 70

High risk: > 70 Others: >70

> 85

24 - 48 hours

> 85

> 120

> 140

49 - 72 hours

> 120

> 155

> 200

> 72 hours

> 140

> 170

> 240

Exchange Transfusion:

Age

Wt <1500g <1500g.

Wt 1500 - 2000g

Wt >2000g

SBR (m mol/L)

SBR (m mol/L)

SBR (m mol/L)

< 24 hours

> 170 - 255

> 255

> 270 - 310

24 - 48 hours

> 170 - 255

> 255

> 270 - 310

49 - 72 hours

> 170 - 255

> 270

> 290 - 320

> 72 hours

> 255

> 290

> 310 - 340

For high risk* premature infants: use lower end of range and weight, next lower weight category, and next lower age category in that order. Use total bilirubin as the exchange criteria unless direct bilirubin is at least 40 mmol/L, then subtract direct from total.

100

40. LISTERIA MONOCYTOGENES INFECTION A. B. C. D. E.

Introduction Clinical Manifestations Investigation Treatment References

A. Introduction: Listeria Monocytogenes is a short Gram-positive rod. Transmission to humans occurs via food, especially dairy products contaminated by infected farm animals. In United States, occurrence rates are 13/100,000 live births. It is less common in Australia. The mortality of neonatal listeriosis is about 5-15%. This infection is classified as a notifable disease.

B. Clinical Manifestations: -

Transplacental infection:

Causes a non-specific influenzal or gastroenteritic illness in pregnant women, during which the organism may infect the fetus either by spread across placenta or through amniotic fluid. First and second trimester infection may cause fetal death. Later in pregnancy infection may precipitate preterm labour with foetal distress and meconium staining of the liquor. Since meconium staining of the liquor is rare below 34 weeks, its presence should raise suspicion of listeriosis. Characteristically, small (2-3mm) pinkish-grey cutaneous granulomas are present and, at autopsy, similar small granulomatous lesions are widespread in the liver, lungs, CNS and many other tissues and organs.

-

Early-onset infection:

60% of infants infected intrapartum are preterm and become ill within 24 hours of birth. Most have disseminated infection with pneumonia, meningitis, thrombocytopenia, anaemia and sometimes conjunctivitis. Both blood and stool should be cultured. Most cases are sporadic, but epidemics are described.

-

Late-onset infection:

Usually presents as meningitis, probably due to nosocomial infection. Median age of onset is about 2 weeks.

C. Investigation: Gram stain can be variable and the organism slow growing.

D. Treatment: • •

Penicillin or ampicillin and gentamicin. Listeria is resistant to all third generation cephalosporins.

E. References: • •

Feigh, R. D., and Cherry, J. D. Textbook of pediatric Infectious Diseases (3rd Ed.). Philadelphia: Saunders, 1992. Stoll, B. J.Weisman, L.E. Infections in perinatology. Clin. Perinatol. 24:1, 1997.

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41. MECONIUM ASPIRATION SYNDROME A. B. C. D. E. F. G. H.

Summary Introduction MAS Pathogenesis Clinical Features Complications Differential Diagnosis Management References

A. Summary: - MAS is characterised by early onset of respiratory distress and hypoxaemia in a meconium–stained term infant - most babies with MAS require nothing more than oxygen therapy and general supportive care; oxygen should -

be used liberally in this condition ventilator support should be instituted where there is refractory hypoxaemia or respiratory acidosis

B. Introduction: Meconium aspiration syndrome (MAS) is an important cause of respiratory distress in the term infant, with a local incidence of around 1.5 in 1000 live births. The prelude to MAS is the passage of meconium at or prior to delivery, a circumstance encountered in 10-20% of all deliveries at term, and more frequently beyond term. Meconiumstained amniotic fluid is rarely seen at preterm delivery; its presence raises the possibility of fetal infection (particularly Listeria).

C. MAS Pathogenesis: In an infant born through MSAF, the risk and severity of MAS is influenced by: - the severity of concurrent asphyxia - the degree of contamination of the amniotic fluid with meconium - the presence of meconium in the airways (nasopharynx, trachea) at delivery Of these, asphyxia is the single most important risk factor for MAS, and is presumed to relate to the influx of MSAF into the lung during hypoxic fetal gasping. MAS can occur, however, in meconium-stained infants that are in good condition at birth. The perinatal events leading to the inhalation of meconium are outlined in Fig 1.

Figure 1. The pathogenesis of MAS (modified from ref 1)

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Once in the lung, meconium quickly migrates down the tracheobronchial tree, inducing a complex lung disease that includes large and small airway obstruction, chemical pneumonitis, proteinaceous alveolar oedema, and surfactant dysfunction (Fig 1). The resultant impairment of gas exchange is often severe, and manifests as hypoxaemia with or without hypercarbia. Persistent pulmonary hypertension with right to left ductal and foramen ovale shunt frequently compounds the oxygenation difficulty.

D. Clinical Features: MAS is characterized by early onset of respiratory distress (within 2 hours) in a meconium-stained infant. Tachypnoea, cyanosis and variable hyperinflation are the main clinical findings. Ausculation reveals widespread "wet" inspiratory crackles, occasionally with expiratory noises suggesting ball-valve airway obstruction. Radiologically the typical progression is from global atelectasis in early X-rays to a widespread patchy opacification accompanied by areas of hyperinflation and/or atelectasis. Blood gas analysis invariably shows hypoxaemia, accompanied by hypercarbia in those infants with significant airway obstruction or severe respiratory failure.

E. Complications: - persistent pulmonary hypertension - air leak – pneumomediastinum, pneumothorax , cystic lung disease - pulmonary haemorrhage - complications of asphyxia – encephalopathy, seizures, oliguria, coagulopathy and thrombocytopenia F. Differential Diagnosis: - birth asphyxia with pulmonary hypertension and/or haemorrhagic pulmonary oedema - transient tachypnoea of the newborn - surfactant deficiency (especially after elective Caesarean delivery) - sepsis/pneumonia - pneumothorax - congenital diaphragmatic hernia G. Management: 1. Delivery room management of the infant born through MSAF: This should consist of airway suctioning (oropharyngeal ± tracheal) followed by respiratory support (oxygen ± positive pressure ventilation)

2. Management of the infant with established MAS: 2.1. Respiratory care: 2.1.1. Oxygen: It cannot be over-emphasised that administration of oxygen is critically important in infants with MAS, and in many infants is the only respiratory therapy needed. The pulmonary vasculature in the term infant is exquisitely sensitive to oxygen tension, and failure to overcome hypoxaemia almost inevitably will lead to progressive pulmonary hypertension. Oxygen should be administered early and liberally in any baby suspected of having inhaled meconium. The suggested target range for oxygen saturation is 94-98%; target PaO2 60 – 90 mm Hg. Oxygen toxicity is not an important consideration in the term infant. 2.1.2. Nasal CPAP: Consider as an interim measure in infants with MAS where there is moderate respiratory distress and hypoxaemia. 2.1.3. Intubation and positive pressure ventilation: Indications: Persistent hypoxaemia (SaO2 < 90%, PaO2 < 50) in 100% oxygen Respiratory acidosis with pH < 7.20 Method: Other than in the delivery room, term infants with MAS require deep sedation and preferably muscle relaxation prior to intubation. Infants with MAS are frequently very difficult to manage once intubated, and often require high peak inspiratory pressures (30 – 35 cm H2O) to achieve gas exchange. Most evidence favours a high positive endexpiratory pressure (6-8 cm H2O), and a long expiratory time. The latter can be achieved using ventilator rates of 40 – 60 breaths per minute, with an inspiratory time of 0.5 – 0.6 secs. Particularly where there is concomitant pulmonary hypertension, deep sedation should be maintained after intubation, and muscle relaxation should be continued if the disease is severe. 2.1.4. Surfactant therapy: Available evidence does not suggest a consistent benefit from bolus surfactant therapy in MAS; many infants show no response, and some acutely deteriorate. Lung lavage using surfactant is currently being investigated in MAS, but cannot yet be recommended as a therapy for this disease. Supportive therapy for pulmonary hypertension

103

2.2. Suctioning: All infants with MAS should have the stomach contents evacuated, and an in-dwelling nasogastric tube inserted. In those intubated, the trachea should be suctioned by small volume saline lavage if there is clinical evidence of build-up of meconium or secretions in the large airways. 2.3. General supportive care:

-

cardiovascular support – volume and inotrope therapy fluid restriction antibiotic therapy – should be continued until primary bacterial infection is excluded IV therapy and nil orally until the respiratory distress is resolving

H. References: •

Wiswell TE, Bent RC. Meconium staining and the meconium aspiration syndrome. Unresolved issues. Pediatr Clin North Am 1993; 40: 955-81.

42. MECONIUM STAINED LIQUOUR, DELIVERY ROOM MANAGEMENT A. B. C. D.

Introduction Management Areas of Uncertainty in Clinical Practice References

A. Introduction: Meconium staining of the liquor complicates approximately 15% of live births. Meconium aspiration syndrome (MAS) may complicate up to 5% of births through meconium stained liquor. MAS carries a significant respiratory morbidity and may be fatal.

B. Management: - At both vaginal and operative deliveries perform thorough suctioning of the mouth and pharynx after

-

-

delivery of the head and before delivery of the shoulders. Guide the catheter into the posterior pharynx via a finger inserted into the infant’s mouth. Use a size 12Fr catheter set at –100mmHg. Repeat the procedure until no further meconium is obtained. Transfer the infant to the resuscitation area and assess infant vigour. A vigorous infant has: • good muscle tone • active breathing efforts • HR>100BPM IF VIGOROUS - provide standard care (see guidelines for resuscitation) IF NOT VIGOROUS – when the operator present is able to perform intubation: • place infant under radiant warmer while avoiding stimulation • insert laryngoscope • suction mouth and pharynx with 12 or 14 Fr catheter (set at –100 mmHg) • insert either 3.0 or 3.5 ET into trachea, attach meconium aspirator, apply suction while withdrawing ET or pass suction catheter directly through the vocal cords and apply suction while gradually withdrawing catheter • repeat until either little meconium is recovered or HR <60BPM (when active resuscitation should commence)

104

-

-

IF NOT VIGOROUS - when the operator present is unable to perform intubation: • place infant under radiant warmer –avoid stimulation • suction mouth and pharynx with 12 or 14Fr catheter (set at -100mmHg) • commence bag and mask ventilation Ongoing care : • Provide continued resuscitation as indicated by condition. • If apnoea or respiratory distress develops subsequently, perform intubation and tracheal suctioning before commencing assisted ventilation • Aspiration of the stomach to prevent risk of aspiration of swallowed meconium is not part of the initial resuscitation since passage of the tube can cause a vagally induced apnoea. Subsequent aspiration of the stomach is recommended after resuscitation is complete. • Admission to SCN for observation is required when there is: o meconium below the cords o ongoing respiratory distress or oxygen requirement o need of active resuscitation involving CPR or prolonged IPPV

C. Areas of Uncertainty in Clinical Practice: There are no randomised controlled trials specifically testing the efficacy of suctioning of the pharynx during birth in preventing MAS. As an incidental finding in their study Wiswell et al showed a threefold increase in MAS among infants where oropharygeal suctioning was not performed. Management of the infant following meconium staining of the liquor by intratracheal suctioning has been based on observational studies dating from 30 years ago. Recent studies have shown that when the infant is vigorous immediately after birth routine intratracheal suctioning did not result in improved respiratory outcomes. There is no evidence that management should be based on consistency of meconium. There is no evidence that techniques used to inhibit gasping after delivery are effective in reducing the incidence of MAS.

D. References: • • • •

Endotracheal intubation at birth for preventing morbidity and mortality in vigorous, meconium-stained infants born at term Halliday HL http://www.cochrane.org/cochrane/revabstr/ab000500.htm Neonatal Resuscitation Textbook, 4th Edition Editor Kattwinkel J.2000 Delivery Room Management of the Apparently Vigorous Meconium-stained Neonate: Results of the Multicenter, International Collaborative Trial WiswellT.E. et al Pediatrics 205(1) Part 1of 3, 2000, 1-7 Resuscitation of the newly born infant Pediatric Working Group of ILCOR. Pediatrics 1999;103(4). http://www.pediatrics.org/cgi/content/full/103/4/e56

43. MENINGOMYELOCELE A. B. C. D. E. F.

Summary Introduction Differential Diagnosis Investigation Management Areas of Uncertainty in Clinical Practice

A. Summary: - infants need early transport to a neonatal centre for assessment - for term infants, without other complicating features, transport by local ambulance services is often appropriate

B. Introduction: The detection of neural tube defects frequently occurs before delivery as a result of maternal alphafetoprotein measurement or ultrasound examination. Referral to a multidisciplinary team for family counselling and management plan development is then appropriate. Genetics Health Services Victoria provides services throughout Victoria and can be contacted via (03) 8341 6201. Occasionally affected infants will deliver unexpectedly. Prognosis for survival and extent of the disability depend on: - the level of the lesion - the degree of involvement of the spinal cord fibres - the presence of associated anomalies: central nervous system (e.g. hydrocephalus, Arnold-Chiari malformation) and others (cardiac, oesophageal, intestinal, and genitourinary anomalies) - the presence of infection

105

C. Differential Diagnosis: Meningocele is a herniation of meninges without associated neural tissue through the bony defect. Following surgical repair there is a good prognosis. Diagnosis is made by appropriate imaging studies (eg ultrasound).

D. Investigation: Detailed clinical examination is required to assess: - site and level of lesion - motor and sensory level - presence of clinical hydrocephalus - presence of hindbrain herniation e.g. stridor, apnoea, swallowing difficulty - presence of musculoskeletal deformity or anomalies of other organ systems

E. Management: Infants need referral and transport to a neonatal centre for assessment by a co-ordinated team of specialists experienced in dealing with these lesions so that a treatment policy can be discussed with the parents. Before and during transport:

-

the lesion, especially if ruptured, should be covered with a sterile non-adherent dressing the infant should be nursed in the prone position and the defect protected e.g. by foam rubber cut into a doughnut

IV access is required to provide antibiotics e.g. Penicillin and Gentamicin (preferably after blood is taken for culture). IV fluids may be required if an excessive delay before oral feeds can commence is anticipated, respiratory difficulty or hypoglycemia is present.

F. Areas of Uncertainty in Clinical Practice: Fetal surgery to close the defect and thus possibly reduce the incidence of hydrocephalus and long term neurological complications remains experimental. Cesarean section before the onset of labour is usually the desired mode of delivery since this has been associated with improved neurological outcomes.

Web links: • • • •

http://www.spinabifida.org This is the Home page of the Spina Bifida Hydrocephalus Association of Queensland. Its great. Plenty of information and good diagrams. http://www.sbaa.org/index.shtml This is the Home page of the Spina Bifida Association of America. Its very good. Spina Bifida Foundation of Victoria. Neural Tube Defects in the Neonatal Period Ellenborgen R.G. eMedicine Journal, July32001, Vol.2, No. 7 http://www.emedicine.com/ped/topic2805.htm

44. METABOLIC DISEASE A NEONATAL APPROACH A. B. C. D. E. F. G. H. I. J. K.

Introduction Patterns Of Presentation Of Metabolic Disease In The Neonate Metabolic acidosis Hypoglycaemia Cardiac disease Liver dysfunction Dysmorphism Fetal hydrops Approach To The Diagnosis Of Metabolic Disease Initial Management Of Suspected Metabolic Disease References

A. Introduction: Whilst individually rare, as a group, metabolic diseases are a significant cause of illness in the neonate. Prior to delivery, a fetus is usually "protected" from any ill-effects of a metabolic disease by virtue of the function of the placenta in providing fuel and filtering toxic metabolites. Many metabolic diseases are thus unmasked in the first days of post-natal life. Their onset may initally be subtle, and the possibility of a metabolic disease must be considered in any infant with non-specific symptoms that are not explicable by another cause.

106

B. Patterns Of Presentation Of Metabolic Disease In The Neonate: The diverse nature of metabolic disease in the newborn is reflected in the modes by which metabolic abnormalities may present. These can be summarised as follows

Neurological presentation:

-

-

-

Symptom-free interval, then lethargy, poor feeding, followed by altered conscious state ± seizures, culminating in coma. Typical of : • organic acidoses (including maple syrup urine disease) • urea cycle disorders Severe neurological abnormality, without symptom-free interval When characterized by encephalopathy, seizures and apnoea typical of: • primary lactic acidoses • non-ketotic hyperglycinaemia • sulphite oxidase deficiency • pyridoxine dependency If associated with profound hypotonia, dysmorphism and/or congenital anomalies: • peroxisomal disorders • mitochondrial disease

C. Metabolic acidosis: Organic acidoses and primary lactic acidoses cause metabolic acidosis with increased anion gap. Whilst initially asymptomatic, as these diseases progress, neurological and circulatory abnormalities inevitably ensue. Given that plasma lactate is now frequently measured in sick neonates, it is important to have a logical approach to high lactate levels. It is firstly necessary to consider whether the sample is adequate - capillary or venous lactate levels may be very high in the face of normal arterial lactate. If arterial lactate is persistently high (> 3 mmol/L), the differential diagnosis is as follows:

-

-

Severe organ dysfunction leading to decrease tissue perfusion/oxygen delivery, or increased metabolic demand: • perinatal asphyxia • congenital heart disease (duct-dependent lesions) • sepsis • untreated seizures Primary lactic acidosis: • disorders of pyruvate metabolism • mitochondrial disorders Secondary lactic acidoses - other metabolic diseases may be associated with lactic acidosis, for example: • fatty acid oxidation defects • organic acidoses • urea cycle defects • sulphite oxidase deficiency)

D. Hypoglycaemia: Low blood glucose in a neonate most usually indicates either:

-

glycogen depletion ± inadequate gluconeongenesis eg premature or SGA infant hyperinsulinism eg infant of a diabetic mother, Beckwith syndrome occasionally hypoglycaemia will be a manifestation of a metabolic disease eg fatty acid oxidation defect, glycogen storage disease

E. Cardiac disease: Cardiac failure and cardiomyopathy can occur in association with mitochondrial, lysosomal or fatty acid oxidation disorders.

F. Liver dysfunction: Persistent hyperbilirubinaemia (conjugated ± unconjugated) may be indicative of a metabolic disease, in particular galactosaemia, but also hypothyroidism, tyrosinaemia, a1-antitrypsin deficiency, and others.

107

G. Dysmorphism: Metabolic diseases associated with dysmorphic features include:

-

peroxisomal disorders (Zellweger syndrome and others) disturbances of energy metabolism (eg pyruvate dehydrogenase deficiency) defects in cholesterol biosynthesis (eg Smith-Lemli-Opitz syndrome) storage disorders

H. Fetal hydrops: A number of metabolic diseases, all individually rare, can cause fetal hydrops.

I. Approach To The Diagnosis Of Metabolic Disease: History and clinical information: Perinatal information that should be sought includes: - a history of previous pregnancy losses - consanguinity - any problems during the pregnancy Detailed clinical examination should be performed, focussing in particular on the cardiorespiratory and neurological status of the infant, supplemented by imaging and metabolic testing as appropriate.

"Screening tests" for metabolic disease:

-

odour of baby and urine (but most babies with malodorous urine do not have metabolic disease) blood glucose serum ammonia acid-base status anion gap ([Na+ + K+] - [Cl- + HCO3-], normal < 12 mmol) lactate - arterial sample liver function tests urinary reducing substances (Clinitest). Remember that glucose is a reducing substance, so if the Clinitest is positive, check the urine specifically for glucose using a glucose oxidase strip urinary ketones urine metabolic screen. A sample of 5-10 mL of freshly-collected urine is needed for this test; the sample can be frozen prior to analysis if necessary. As much clinical information as possible should be included on the request card to assist in the interpretation of the results

In only a few cases will the results of the above "screening" tests pinpoint the exact metabolic defect. They will, however, identify infants with a high likelihood of having a metabolic disease, in whom further tests would be performed as appropriate. The details of these tests is beyond the scope of this work, see reference 2 for details.

J. Initial Management Of Suspected Metabolic Disease: If a metabolic disease is suspected, it is highly recommended that the case be discussed with a physician conversant with the management of metabolic disease in the neonate. Where the index of suspicion is high, or the infant is significantly unwell, transfer to a tertiary centre should be arranged, with interim treatment measures commenced as outlined below.

General measures: Infants with metabolic disease frequently require vigorous supportive measures to stabilise their physiological state. Examples of commonly encountered problems, and the appropriate responses are: - profound encephalopathy or apnoea - mechanical ventilation - circulatory failure - intravascular volume expansion, ± inotrope therapy - seizures- anticonvulsant therapy

Specific therapy: In addition to general supportive measures, in some cases specific treatment should be instituted as soon as a metabolic disease is recognised. Examples of the reponse in specific situations are:

-

any case where metabolic disease appears likely - cease oral feeds and administer 10% dextrose ± electrolytes (milk is the source of toxic metabolites in many metabolic diseases). Give dextrose at an infusion rate of at least 5 mg/kg/min (=3 mL/kg/hr of 10% dextrose). Many metabolic diseases are aggravated by tissue catabolism; a higher rate of dextrose infusion may be required beyond 24 hours

108

-

-

hyperammonaemia - sodium benzoate (250 mg/kg loading dose over 1-2 hrs, infusion of 250 mg/kg/24 hrs). This is an interim measure to clear waste nitrogen; resolution of hyper-ammonaemic coma usually requires haemodialysis hypoglycaemia - dextrose infusion to maintain euglycaemia (may need to use a dextrose concentration > 10%, ideally through an umblicial venous catheter) metabolic acidosis - correct pH using sodium bicarbonate. The formula for "half-correction" of a metabolic acidosis is: • amount of HCO3- to infuse (in mEq) = (base deficit x weight) / 4 • repeated NaHCO3 corrections may be required, in which case beware of hypernatraemia suspected organic acidosis/fatty acid oxidation defect - give carnitine 100 mg/kg/day in 4 divided doses until the results of metabolic tests are at hand

For details of further acute management, and the ongoing care of infants with metabolic disease, the interested reader is referred to reference 2.

K. References: • •

Chakrapani A, Cleary MA, Wraith JE. Detection of inborn errors of metabolism in the newborn. Arch Dis Child 2001; 84: F205-10. Hoffman GF, Nyhan WL, Zschocke J, Kahler SG, Mayatepek E. Inherited metabolic diseases. Philadelphia: Lippincott Williams & Wilkins, 2002

45. NECROTISING ENTEROCOLITIS A. B. C. D. E. F. G. H. I. J. K.

Summary Introduction Risk factors Clinical Presentation Differential Diagnosis of suspected NEC Radiographic findings Management Complications Prevention Areas of uncertainty: References

A. Summary: -

NEC is the most common GI emergency in neonates NEC can present late in tiny babies early or ‘possible’ NEC is difficult to diagnose – if in doubt treat early and conservatively (nil by mouth and broad spectrum antibiotics) babies with ‘definite’ NEC should be referred to a NICU babies with ileostomies: • need supplemental sodium • can become rapidly dehydrated with gastroenteritis strictures can present many weeks after NEC

B. Introduction: Necrotising enterocolitis (NEC) is the most common gastrointestinal (GI) emergency in neonates. Ninety percent of babies with NEC are preterm. It is predominantly a disease of the very low birthweight infant and is most common in babies < 1000 g or those that are both preterm and growth restricted. The incidence of NEC is inversely proportional to birthweight. In general, the age of onset is inversely proportional to gestation; therefore smaller babies present later. Approximately 50% of babies developing NEC require surgery. The mortality rate of NEC is 20-40%. Of those who survive, approximately 25% develop long term sequelae. Early or suspected NEC is often difficult to diagnose as the clinical signs and symptoms are often non-specific, as are the radiological and laboratory findings. As babies with definite NEC should be transferred to a level III unit, this topic will concentrate mainly on the presentation and diagnosis of NEC as well the level II management of a baby who has had previous NEC.

109

C. Risk factors: - prematurity - enteral feeding (although approx. 10% of cases occur in infants never fed) - formula feeding (6 times more common than if only breast milk fed) - often occurs in clusters (although organisms vary) - bowel ischaemia - in term infants: • • • •

polycythaemia cardiac surgery abdominal surgery (esp. gastroschisis, intestinal atresia) endocrine abnormalities

D. Clinical Presentation: - clinical signs and symptoms are highly variable but include - GI dysfunction: • • • •

-

-

abdominal distention vomiting bilious drainage from enteral feeding tubes blood in stool systemic: • temperature instability • apnoea and/or bradycardia • lethargy • hypotension the severity, radiology and management of NEC is best exemplified by the ‘Modified Bell’s Staging Criteria’ Modified Bell’s Staging Criteria for Necrotizing Enterocolitis:

STAGE

SYSTEMIC SIGNS

INTESTINAL SIGNS

RADIOLOGIC SIGNS

TREATMENT

I. Suspected A

Temperature instability, Elevated pregavage apnoea, bradycardia residuals, mild abdominal distension, occult blood in stool

Normal or mild ileus

NPO, antibiotics x 3 days

B

Same as IA

Same as IA, plus gross blood in stool

Same as IA

Same as IA

A: Mildly ill

Same as IA

Same as I, plus absent bowel sounds, abdominal tenderness

Ileus, pneumatosis intestinalis

NPO, antibiotics x 7 to 10 days

B: Moderately ill

Same as I, plus mild metabolic acidosis, mild thrombocytopenia

Same as I, plus absent Same as IIA, plus portal NPO, antibiotics bowel sounds, definite vein gas, with or without x 14 days abdominal tenderness, ascites abdominal cellulitis, right lower quadrant mass

A: Severely ill, bowel intact

Same as IIB, plus hypotension, bradycardia, respiratory acidosis, metabolic acidosis, disseminated intravascular coagulation, neutropenia

Same as I and II, plus signs of generalised peritonitis, marked tenderness and distension of abdomen.

Same as IIB, plus definite ascites

NPO, antibiotics x 14 days, fluid resuscitation, inotropic support, ventilator therapy, paracentesis

B: Severely ill: bowel perforated

Same as IIIA

Same as IIIA

Same as IIB, plus pneumoperitoneum

Same as IIA, plus surgery

II. Definite

III Advanced

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E. Differential Diagnosis of suspected NEC: - dysmotility of prematurity - septic ileus - bowel obstruction - gastroenteritis - anal fissure - cow’s milk protein sensitive enterocolitis F. Radiographic findings: - nonspecific: • • • • • •

-

diffuse gaseous distension asymmetric, disorganised bowel pattern ‘featureless’ loops dilated bowel loops bowel wall thickening increased peritoneal fluid diagnostic signs: • persistent loop • pneumatosis intestinalis (virtually pathognomonic): ƒ submucosal – bubbly or cystic appearance (may be confused with stool, although stool usually moves on serial x-rays) ƒ subserosal – linear or curvilinear appearance • portal venous gas • pneumoperitoneum (although may not be due to NEC)

G. Management: - see ‘Modified Bell’s Staging Criteria’ for duration - nil by mouth - gastric tube on free drainage - blood culture - antibiotics: • • •

-

vancomycin gentamicin metronidazole ( only for definite NEC) cases of definite NEC should be referred to a level III NICU for management, as the following (may be) required: • gut rest for 10-14 days • total parenteral nutrition • fluid management • inotropes • ventilation • analgesia • frequent radiographs • surgery (25% to 50% of cases)

H. Complications: -

surgery requiring ileostomy: • require supplemental sodium even when well • high risk of rapid dehydration with gastroenteritis stricture 20-30% most commonly bin large bowel 80% on left side may not develop for weeks to months post-NEC presents with recurrent abdominal distension surgical consultation and contrast enema required

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I. Prevention: -

antenatal corticosteroids early intervention (nil orally) for suspected NEC breast milk infection control practices may limit the size of disease clusters

J. Areas of uncertainty: - effect of rate of feed upgrade in the prevention of NEC - prophylactic antibiotics (proven to reduce NEC risk but concern re development of antibiotic-resistant -

organisms) enteral IgA (enteral IgG refuted)

K. References: • • •

Taeusch HW, Ballard RA. Avery’s Diseases of the Newborn 7th Ed. W.B. Saunders Company, Philadelphia. 1998 Chandler JC, Hebra A. Necrotizing enterocolitis in infants with very low birth weight. Sem Pediatr Surg 2000;9:63-72 Buonomo C. The radiology of necrotizing enterocolitis. Radiol Clinics North Amer 1999;37:1187-98

Other Reading/Web links: • •

Neu J, Weiss MD. Necrotizing enterocolitis: Pathophysiology and prevention. J Parenteral Enteral Nutrition 1999;23:S13-7 Caplan MS, Jilling T. New concepts in necrotizing enterocolitis. Current opinion in Pediatrics 2001;13:1115

46. NORMAL LABORATORY VALUES A. B. C. D. E. F. G. H. I. J. K.

Summary Introduction Term infants (age of life) Acid Base Values* - Term and Preterm infants (by age of life) Electrolytes - Preterm infants (< 37 weeks) (by day of life): Other Biochemistry - Preterm infants (by gestation): Haematology - Preterm infants (by age): Coagulation Profile - Preterm infants (by age): CSF - Term and Preterm infants (by age of life): Urine — Term and Preterm infants References

A. Summary: -

consider laboratory error if spurious result in well baby where possible, use local laboratory reference ranges laboratory tests are only useful if they guide management

B. Introduction: In general, normal values are readily available for healthy term infants. As (extreme) prematurity is a pathological condition in itself, one has to be a little cautious in using the concept of ‘normal’. In most cases, when considering the correction of ‘abnormal’ values, it is wise to consider the following:

-

is this due to sampling or laboratory error? is the baby symptomatic? what is the evidence that correcting the abnormality is beneficial? is there any risk or danger in correcting an abnormal result?

It is always advisable to keep in mind the reference ranges from your own laboratory as they will be analyser or population specific. This is particularly important with respect to coagulation profiles, for example. If your laboratory does not provide reference ranges for newborns or subsets thereof, the following may be helpful. (N.B. mm/L = micromol/litre). See relevant links for blood glucose and serum bilirubin levels.

112

C. Term infants (age of life): Value

Cord

1-12 hr

12-24 hr

24-48 hr

48-72 hr

Na (mEq/L)

147(126-166) 143(124-156) 145(132-159)148(134-160) 149(139-162)

K (mEq/L)

7.8 (5.6-12)

6.4 (5.3-7.3) 6.3 (5.3-8.9)

6.0 (5.2-7.3)

5.9 (5.0-7.7)

Cl (mEq/L)

103(98-110) 101(80-111) 103(87-114)

102(92-114)

103(93-112)

Ca (mm/L)

2.33(2.1-2.8) 2.1 (1.8-2.3) 1.95(1.7-2.4) 2.0 (1.5-2.5)

1.98(1.5-2.4)

1.05-1.37

Ca (I) (mm/L) PO4 (mm/L)

1.8(1.2-2.6)

0.72-1.00

1.10-1.44

1.20-1.48

0.81-1.05

0.78-1.02

10.4(7.5-14.3 9.6(2.9-12.1) 11.8(3.2-22.5)11.4(4.6-27.5)11.1(5.4-24.3) 0.04-0.11

Creat (mm/L) CRP (mg/L)

1.05-1.37

1.97(1.1-2.8) 1.84(0.9-2.6) 1.91(1.0-2.8) 1.87(0.9-2.5)

Mg (mm/L) Urea (mm/L)

1.05-1.37

3-10 d

<7

Lactate(mm/L) 1.5-4.5

<7

<7

0.9-2.7

0.8-1.2

<7

0.01-0.09 <7

<7

0.5-1.4

Albumin (g/L)

28-43

28-43

28-43

28-43

28-43

30-43

ALP (IU/L)

28-300

28-300

28-300

28-300

28-300

28-300

T4

8.2 (+/-1.8)

19.0 (+/-2.1) 19.0 (+/-2.1) 19.0 (+/-2.1) 15.9 (+/-3.0) 3.0-120

TSH Cortisol(nm/L)

200-700

200-700

3.0-30

0.3-10

200-700

17-OHP (nm/L)

0.7-12.4

0.7-12.4

Hb (g/Dl)

16.8

18.4

17.8

17.0

Hct (%)

53

58

55

54

MCV

107

108

99

98

Retic (%)

3-7

3-7

1-3

0-1

WCC x 109/L

18.1 (9-30)

22.8 (13-38) 18.9 (9.4-34)

12.2 (5-21)

Neutrox109/L

11.1 (6-26)

15.5 (6-28)

11.5 (5-21)

5.5 (1.5-10)

Lymphx109/L

5.5 (2-11)

5.5 (2-11)

5.8 (2-11.5)

5.0 (2-17)

Mono x 109/L

1.1

1.2

1.1

1.1

Eosin x 109/L

0.4

0.5

0.5

0.5

Plat(103/mm3)

150-350

150-350

150-350

150-350

150-350

150-350

PT (sec)

11-14

11-14

11-14

11-14

11-14

APTT (sec)

23-35

23-35

23-35

23-35

23-35

FBG (mg/dL)

200-400

200-400

200-400

200-400

200-400

Capillary refill

< 3 seconds

< 3 seconds

< 3 seconds

< 3 seconds

< 3 seconds

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D. Acid Base Values* - Term and Preterm infants (by age of life:) Value

Cord

1-12 hr

12-24 hr

24-48 hr

Range**

PH

7.33 (UV)

7.30 (art)

7.30 (art)

7.39

7.25-7.45

PCO2 (mmHg)

43 (UV)

39

33

34

35-50

HCO3 (mEq/L)

21.6 (UV)

18.8

19.5

20

17-28

PO2 (mmHg)

28 (+/-8) (UV)

62 (+/-13.8)

68

63-87

60-80

Anion gap

<20

<20

<20

<20

8-16

* Capillary ranges similar except pO2 (see link) ** Very difficult to define, wide variation within/between level III Units

E. Electrolytes - Preterm infants (< 37 weeks) (by day of life): Value

Day 1

Day 3

Day 7

Na(mEq/L)

140(133146)

140(133 146)

140 (133146)

K (mEq/L)

5.6 (4.66.7)

5.6 (4.66.7)

5.6 (4.6-6.7)

Cl (mEq/L)

108 (100117)

108(100117)

Ca (mm/L)

2.3 (1.52.9)

Ca (I) (mm/L) 0.81-1.41

Day 21

Day 35

Day 49

137(133-148)

137 (133142)

5.8 (4.5-7.1)

5.5 (4.5-6.6)

5.7 (4.6-7.1)

108 (100117)

108(102116)

107 (100115)

107 (101115)

2.3 (1.52.9)

2.3 (1.5-2.9)

2.4 (2.0-2.8)

2.4 (2.2-2.6)

2.4 (2.2-2.7)

0.72-1.44

1.04-1.52 (d5)

1.04-1.52

1.04-1.52

1.04-1.52

36(129-142)

PO4 (mm/L)

2.5 (1.73.5)

2.5 (1.73.5)

2.5 (1.7-3.5)

2.4 (2.0-2.8)

2.3 (1.8-2.6)

2.2 (1.4-2.7)

Mg (mm/L)

0.62-1.02

0.66-1.10

0.75-1.00

0.75-1.00

0.75-1.00

0.75-1.00

Urea (mm/L)

3.3(1.1-9.1) 3.3(1.1-9.1) 3.3 (1.1-9.1)

4.8(0.8-11.2)

4.8 (0.7-9.5)

4.8 (0.9-10.9)

F. Other Biochemistry - Preterm infants (by gestation): Value

27 weeks

29 weeks

31 weeks

33 weeks

35 weeks

Alb (g/L)

21-33

23-34

22-35

22-35

22-36

ALP (IU/L)

35-604

119-465

112-450

110-398

113-360

Creat (mm/L) day 2

0.08-0.16

0.07-0.14

0.07-0.14

0.05-0.13

0.05-0.13

Creat (mm/L) day 7

0.05 -0.11

0.04-0.12

0.04-0.12

0.02-0.11

0.02-0.11

Creat (mm/L) day 14

0.04-0.10

0.04-0.10

0.04-0.10

0.02-0.09

0.02-0.09

Creat (mm/L) day 21

0.03-0.09

0.03-0.09

0.03-0.09

0.02-0.09

0.02-0.09

Creat (mm/L) day 28

0.03-0.08

0.02-0.09

0.02-0.09

0.01-0.06

0.01-0.06

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G. Haematology - Preterm infants (by age): Value

Birth

Hb (g/dL)

14.0(24wks)

12 hours

24 hours

1 week

2 weeks

1 month

14.5(28wks) 15.0(34wks) WCC x 109/L

18.1 (9-30)

22.8 (13--38)

18.9 (9.4-34)

12.2 (5-21)

11.4 (5-20)

10.8(5-19.5)

Neutro x 109/L

11.1 (6-26)

15.5 (6-28)

11.5 (5-21)

5.5 (1.5-10)

4.5 (1-9.5)

3.8 (1-9)

Lymph x 109/L

5.5 (2-11)

5.5 (2-11)

5.8 (2-11.5)

5 (2-17)

5.5 (2-17)

6.0(2.5-16.5)

Monox 109/L

1.1

1.2

1.1

1.1

1.0

0.7

Eosinx 109/L

0.4

0.5

0.5

0.5

0.4

0.3

Plat(103/mm3)

150-350

150-350

150-350

150-350

150-350

150-350

H. Coagulation Profile - Preterm infants (by age): Value

Day 1

Day 5

Day 30

PT (sec)

13 (10.6-16.2)

12.5 (10-15.3)

11.8 (10-13.6)

APTT (sec)

53.6 (27-79)

50.5 (27-74)

44.7 (27-62)

FBG (g/L)

2.43 (1.5-3.7)

2.8 (1.6-4.2)

2.54 (1.5-4.14)

I. CSF - Term and Preterm infants (by age of life): Value

Term < 7d

Term > 7d

Preterm < 7d

Preterm > 7d

WCC (mm3)

5 (0-30)

3 (0-10)

9 (0-30)

12 (2-70)

RCC (mm3)

9 (0-50)

<10

30 (0-333)

30

Protein (g/L)

0.6 (0.3-2.5)

0.5 (0.2-0.8)

1 (0.5-2.9)

0.9 (0.5-2.6)

Glucose (mm/L)

3 (1.5-5.5)

3 (1.5-5.5)

3 (1.5-5.5)

3 (1.5-5.5)

J. Urine — Term and Preterm infants: Value

Term < 7d

Term > 7d

Preterm < 7d

Preterm > 7d

WCC (per HPF)

<5

<5

<5

<5

RCC (per HPF)

0-2

0-2

0-2

0-2

Squames (per HPF)

<5

<5

<5

<5

Organisms

Nil

Nil

Nil

Nil

K. References: • •

Rennie JM, Roberton NRC (Eds). Textbook of Neonatology, 3rd Ed. Churchill Livingstone, Edinburgh, 1999. Taeusch HW, Ballard RA (Eds). Avery’s Diseases of the Newborn 7th Ed. W.B. Saunders Company, Philadelphia. 1998

115

47. OSTEOPENIA OF PREMATURITY A. B. C. D. E.

Introduction Diagnosis of metabolic bone disease Considerations and recommendations for enteral feeding What this means for very premature babies. Length of supplementation.

A. Introduction: This can be a significant problem for very premature babies and there is some suggestion that hypophosphataemia prolongs the need for ventilatory support. Some very premature babies have very "thin" bones on their x-rays.

B. Diagnosis of metabolic bone disease: -

biochemical tests of osteopenia of prematurity are not definitive serum Phosphate: suspicious if <1.5, likely if < 1.1 mmol/L the alkaline phosphatase (ALP) is more elevated than usual for preterm babies. Levels above 600 or 800 IU/L are quoted. However, the ALP only rises high if there is bone turnover. If the condition is very severe the ALP may not be very high the calcium level may be normal, elevated or even low a bone x-ray will show very poor mineralisation and as the infants grow can show changes of rickets or fractures an abnormal Ca++ : PO4 ratio in the urine. In normal infants it is less than 1.0 (both measured in mmol/L))

Conversion factors (One of the problems with this area is that the USA, and many books, work in mg, while Australia and Europe use mmol/L)

Ca++

1 mmol = 40 mg

PO4-

1 mmol = 31 mg

Mg++ 1 mmol = 24 mg

C. Considerations and recommendations for enteral feeding: Fetal retention rates per day in mid to third trimester

Human Milk per 100ml. Approx

FM85 per 5g

HM 100ml + 5g FM85

Fortified EBM @ 180 ml/kg/d the baby gets about

Recommended per150 ml/kg/d (Probably needs to be at top end)

Ca

2.3 to 3.0 mmol/kg 0.75 mmol 90 – 120 mg kg (30 mg)

1.3 mmol (51 mg)

2.0 mmol (81 mg)

3.6 mmol (146 mg)

3.0 to 5.7 mmol (120 – 230 mg)

PO4

1.9 to 2.4 mmol/kg 0.5 mmol 60 - 75 mg/kg (15 mg)

1 mmol (34 mg)

1.6 mmol (49 mg)

2.9 mmol (88 mg)

1.9 to 4.5 mmol (60 – 140 mg)

0.08 mmol (2.0 mg)

0.23 mmol (5.5 mg)

0.4mmol(9.9mg)

0.33 to 0.63mmol (7.9 to 15 mg)

Mg 0.10to 0.14mmol/kg 0.15 mmol 2.4 – 3.4 mg/kg (3.5 mg)

Remember that not all the minerals given are absorbed and retained. Retention rates for enteral nutrition vary but are about 50-60% for calcium, 70-80% for phosphorus and 50% for magnesium.

D. What this means for very premature babies: Premature infants fed with fortified EBM at 150 ml/kg/day, or more, should be getting just about enough calcium and phosphate. However, they need to be monitored and may still need supplementing. Fortification of feeds should start as early as possible – as soon as they are tolerating 120 ml/kg. Vitamin D about 500 IU/day is required. Pentavite provides 405 units per day. Larger doses have no increased benefit.

116

Extra phosphate supplementation. If a baby needs supplementation then a solution of phosphate 0.8 mmol/ml is made by dissolving one tablet of Sandoz phosphate in 20 ml water. Begin supplementation with 3 mmol/kg/day in 3 divided doses (i.e. 1 mmol/kg/dose tds). The dose should then be titrated against the blood phosphate level over the following weeks. Stop phosphate supplements if the serum phosphate is >1.8 mmol/L Monitoring. "bone bloods" should be monitored every two weeks in very premature babies unless they are found to be phosphate depleted and if supplements are given they should be measured every week.

E. Length of supplementation: No one really knows how long to go on supplementing with phosphate. However it is worth considering that the babies are still growing fast up to and beyond "term".

48. PARVOVIRUS INFECTION A. B. C. D. E. F.

Introduction Clinical manifestations Investigation Treatment Management of pregnant women at risk for parvovirus exposure Reference

A. Introduction: Human Parvovirus B19 is a small unenveloped virus containing single stranded DNA and is responsible for several clinical syndromes. Normal transmission is presumably by the respiratory route via droplet aerosol. Most children have encountered the virus by their teenage years but those who escape infection as children are susceptible as adults. Parvovirus can be transmitted across the placenta posing a potential threat to the fetus.

B. Clinical manifestations: - fetal infection - Primary maternal infection has been associated with nonimmune fetal hydrops and intrauterine fetal demise. The pathogenic sequence is transplacental transfer of B19 virus - infection of RBC precursors - arrested RBC production- severe anemia - congestive heart failure - oedema The overall vertical transmission rate to the fetus is approximately one third. The attack rate for severe fetal disease (hydrops) is approximately 5% following infection during the first 18 weeks. Infection occurring beyond 18 weeks have been associated with anemia. B 19 has been detected in cardiac tissue causing myocarditis, and can also cause fetal hepatitis with severe liver disease.

-

-

erythema Infectiosum (Fifth disease) - Most common manifestation of B19. A benign, self-limiting exanthematous illness of childhood. The hallmark is a characteristic "slapped cheek" rash. The rash spreads rapidly to the trunk and proximal extremities as a diffuse macular erythema. The palms and soles are spared, and the rash tends to be more prominent on extensor surfaces. Central clearing of macular lesions occurs promptly, giving the rash a lacy, reticulated appearance. The rash resolves spontaneously without desquamation but tends to wax and wane over 1- 3 weeks. individuals with chronic hemolytic conditions may experience transient red cell aplastic crises arthritis and arthralgia of small joints may complicate fifth disease or be the sole clinical manifestation of infection chronic infection may occur in the immunocompromised host causing chronic anemia or complete marrow suppression

C. Investigation: Measure serum IgG and IgM levels. IgM levels appear by day 3 of an acute infection and begin to fall by 2 to 3 months after infection. IgG appears a few days after IgM and may persist for years. Viral antigens may be directly detected in tissues by radioimmunoassay, ELISA, immunofluorescence, in situ nucleic acid hybridization, or PCR.

D. Treatment: Treatment is generally supportive. There are case reports of successful use of Intravenous gamma globulin (IVIG) in patients with severe hematologic disorders. IVIG prophylaxis may be considered in immunocompromised patients exposed to B19 infection, however, IVIG is not currently recommended for prophylaxis in pregnancy.

117

E. Management of pregnant women at risk for parvovirus exposure: Measurement of serum IgG and IgM levels may be useful to determine those at risk or acutely infected after B19 exposure. These tests should generally limited to pregnant women clearly at increased risk for acute B19 exposure during the first 18 weeks of gestation. Consultation with an infectious disease physcian is reccommended.

F. References: • • • • •

Bishara J. Freij and John L. Sever. Textbook of Neonatology. Gordon B. Avery (5th Ed). Philadelphia: Lippincott Williams & Wilkins, 1999 Stoll, B. J., Weiseman, L. E. Infections in perinatology. Clin. Perinatol. 24:1, 1997. Brown KE, Young NS. Human parvovirus B19 infection in infants and children. Adv Pediatr Infect Dis 1998; 13:101. Sandra K. Burchett. Manual of neonatal care. John P. Cloherty (4th Ed). Philadelphia: Lippincott-Raven, 1998. Samuel P.Gotoff. Textbook of pediatrics. Behrman (16th Ed) Philadelphia: W. B. Saunders Company

49. PERCUTANEOUS CENTRAL VENOUS CATHETER INSERTION A. B. C. D. E. F. G. H. I. J.

Indications Equipment Required For Infants < 1000 g For Infants > 1000 g Contraindications Procedure Ongoing Management Complications Catheter Removal References

A. Indications: Peripherally inserted central venous catheters are used when an infant requires repeated and prolonged venous access for the delivery of: - medications - fluids - nutritional solutions

B. Equipment Required: - equipment trolley - sterile instrument tray - mask, gown and sterile gloves - disposable tape measure - Persist Plus (multi-pack) - 1 ampoule of 0.9% sodium chloride - 2 x 10 ml syringe - 2 x 16 GA drawing up needle - 1 x 10 ml ampoule of Omnipaque (180 mg Iodine/ml) C. For Infants < 1000 g: L-CATH 28GA single lumen POLYURETHANE catheter. This catheter is 20 cms long and is introduced via a metal splitting needle. If necessary this catheter can be shortened using the trimming tool which is provided with the kit. The maximum flow rate is 38 ml/hr. Premicath 27GA single lumen POLYURETHANE catheter. This catheter is 20 cms and is introduced via a metal splitting needle. There are catheter markings every 5 cms. The priming volume is 0.14 mls. The maximum flow rate is 30 ml/hr.

D. For Infants > 1000 g: L-CATH 24GA single lumen POLYURETHANE catheter. This catheter is 30 cms long and is introduced via a metal splitting needle (U-Wing needle introducer). If necessary this catheter can be shortened using the trimming tool which is provided with the kit. The maximum flow rate is 50 ml/hr.

118

First PICC 20GA single lumen SILICONE catheter. This catheter is 50 cms long and is introduced via a 19GA plastic peel-away needle (Introsyte precision introducer). This catheter can be trimmed but only with the special purpose trimmer (not available until 2002). The maximum flow rate is >100 ml/hr. Epicutaneo-cave Neocath single lumen SILICONE catheter. This catheter comes in 30 cms and 50 cm lengths. The kit comes with a 19GA butterfly style introducer needle, which can be removed after insertion because of the removable Easy-lock extension tube. The 19GA butterfly needle is very large and sometimes difficult to insert. A 22GA Insyte cannula may also be used to insert the central line. If inserting the line via the saphenous vein in a large infant, remember to choose the 50 cm catheter. In a term baby, 30 cms isn't long enough to site the tip of the catheter above the diaphragm. The priming volume of the 30 cm catheter is 0.2 mls and the the priming volume of the 50 cm catheter is 0.29 mls. The maximum flow rate is >100 ml/hr.

E. Contraindications: - Infection - systemic or cutaneous near the proposed point of insertion - Anatomical irregularities in the baby's extremities or chest that could interfere with proper placement of the catheter

F. Procedure: - select an appropriate vein (the basilic and long saphenous veins are preferred) - determine the length of catheter to be inserted by measuring the distance between the proposed insertion -

-

-

-

site and the mid-sternum secure mask open the sterile tray and catheter wash hands with chlorhexidene and don gown and sterile gloves apply a tourniquet if required flush the catheter with sterile saline prepare the insertion site with Persist Plus and allow to dry. Skin cleansing at the insertion site is one of the most important measures in preventing catheter-related sepsis using a 10 ml syringe draw up and flush the catheter with sterile saline use slight tension on the skin to stabilise the vein and then insert the introducer needle into the vein. Release the tourniquet. Stabilise the introducer needle to maintain its position in the vein and holding the catheter through the protective sleeve, use fingers or smooth forceps to carefully advance the catheter in short increments approximately 5 cms into the vein withdraw the introducer needle completely out of the insertion site keeping the needle parallel with the skin to avoid cutting the catheter. To separate the introducer needle from the catheter, remove the clip that holds the two halves of the introducer needle together. Grasp opposite halves of the introducer needle by the front wing portions and pull the two halves of the needle apart until the needle splits completely. The Epicutaneo-cave Neocath doesn't have a splitting introducer needle and is removed from the catheter by unscrewing the blue Easylock connector. When reconnecting ensure that the catheter is fully inserted into the hub (the black mark on the catheter shouldn't be visible). discard the needle into "sharps" container advance the catheter in short increments to desired position. To help with proper placement of the tip turn the infant's head toward the access side with the chin on the shoulder remove the stylet slowly and steadily from the catheter. (Note that the Epicutaneo-cave Neocath does not have an introducer stylet.) flush the catheter with 0.9% normal saline verify the position of the catheter by X-ray before use making sure that the entire length of the catheter is visualised Using a 5 ml syringe inject the contrast medium (Omnipaque 180 mg Iodine/ml) and ask the radiographer to take the chest x-ray whilst still injecting. The catheter dead space is very small (0.1-0.2 ml) so only inject 0.2-0.5 ml of contrast medium. A 5 ml syringe must be used because rapid injection with a 1 or 2 ml syringe is capable of generating pressures above the catheter bursting pressure. The contrast medium does NOT require dilution. Preferable tip locations include superior or inferior vena cava just outside the right atrium. If the catheter tip is beyond the desired position it can be withdrawn. Catheters that are not far enough in may only be advanced if the insertion site is still sterile. the decision to use a catheter that is not centrally located must be made after a careful assessment of the necessity of needing vascular access versus the higher risk of catheter complications secure the catheter by taping it flat against the skin using "steri-strips". Place the catheter hub on a small roll of sterile gauze. Cover the insertion site and hub with Tegaderm. Take care not to completely wrap the Tegaderm around the limb. Using sterile technique connect the catheter to a bag of infusion fluid in the Patient's history record the catheter length inserted, catheter type and gauge, insertion site, location of catheter tip and the date of insertion

119

G. Ongoing Management: - routine dressing changes are not necessary because of the risk of bacterial contamination and accidental

-

dislodgment of the catheter. The dressing should be changed if: • it becomes insecure • the catheter becomes twisted or kinked • if there is evidence of bleeding or inflammation blood or blood products should not be routinely infused through the PCVC. The catheters may rupture if subjected to high pressure. This is most likely to occur if the catheter is flushed using a 1 or 3 ml syringe. Therefore the catheters should only be flushed using a 10 ml syringe.

H. Complications: - Infection. The commonest complication although one randomised trial suggests that infection is no more -

common in central than peripheral lines Thrombosis - more likely to occur if the line has not been advanced into a large central vein Extravasation has occurred into the skin and pleural, pericardial and epidural space The introducer needle can inadvertently cut the catheters when the severed end of the catheter may embolise into the infant.

I. Catheter Removal: The catheter should be removed when:

-

its use can be no longer justified bacteraemia and/or clinical symptoms persisting beyond 48-72 hours despite appropriate antibiotic therapy septicaemia due to fungal infection evidence of septic emboli or endocarditis

Use sterile technique when removing the catheter.Tto remove the catheter, grasp the catheter tubing, not the Luer hub, and pull in a slow, continuous movement, keeping the catheter parallel to the vein. If the catheter has been removed because of suspected sepsis the tip should be sent to for microbiological examination. Catheter tips are not routinely sent for microbiological examination.

J. References: • • • • • • •

Percutaneous Central Venous Ctheterisation protocol, Southern Health Care Network - Monash Medical Centre, Newborn Services Janes M, Kalyn A, Pinelli J, Paes, B. A randomized trial comparing peripherally inserted central venous catheters and peripheral intravenous catheters in infants with very low birth weight. Journal of Pediatric Surgery, Vol 35, No 7 (July), 2000: pp 1040-1044. Zenker M, Rupprecht T, Hofbeck M, Schmiedl N, Vetter V, Ries M. Paravertebral and intraspinal malposition of transfemoral central venous catheters in newborns. J Pediatr 2000;136:837-40. Benjamin, D, Miller W, Garges H et al. Bacteremia, central catheters, and neonates: When to pull the line. Pediatrics 2001;107:1272-1276. Racadio J, Johnson N, Doellman D. Peripherally inserted central peripherally inserted central venous catheters: Success of scalp-vein access in infants and newborns. Radiology 1999; 210:858-860. Bagwell C, Salzberg A, Sonnino R, Haynes J. Potentially lethal complications of central venous catheter placement. J Pediatr Surg 35:709-713. Product information (L-Cath and First PICC)

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50. PERSISTENT PULMONARY HYPERTENSION OF THE NEWBORN A. B. C. D. E. F. G.

Summary Introduction Differential Diagnosis Investigation Management Areas of Uncertainty in Clinical Practice References

A. Summary: -

diagnosis should be confirmed by cardiac echo as soon as feasible appropriate support of ventilation with liberal oxygenation is important early consultation with NETS is advisable support of systemic BP with inotropes is useful nitric oxide is safe and usually effective in PPHN up to a dose of 20ppm

B. Introduction: One of the main tasks facing a fetus making the transition to the extra-uterine environment is that of cardiopulmonary adaptation. Central to this process is a dramatic drop in pulmonary vascular resistance. This is due to a number of influences including:

-

mechanical stretching of the lungs increased oxygen levels in the blood vascular endothelial factors including nitric oxide

Delayed relaxation of the pulmonary vascular bed and consequent PPHN is seen in association with many neonatal respiratory diseases including:

-

lung hypoplasia (e.g. diaphragmatic hernia) meconium aspiration syndrome pneumonia surfactant deficiency The syndrome may also be seen in the absence of triggering diseases.

Right to left shunting across the ductus arteriosus and foramen ovale characterizes PPHN, hence the alternate name Persistent Fetal Circulation. A "vicious cycle" of worsening hypoxia causing increasing pulmonary vascular resistance in turn reducing oxygen uptake provides a substantial therapeutic challenge. Therapies for PPHN are largely untested in randomized controlled trials and many controversies about management strategies remain.

C. Differential Diagnosis: Structural heart disease needs to be excluded when PPHN is considered a likely diagnosis.

-

-

echocardiography is the definitive diagnostic tool but is not always available clinical examination is of limited value. A single second heart sound is present in many cyanotic heart defects and clinical or radiological evidence of cardiac failure suggests structural cardiac disease the use of pre-ductal and post-ductal oxygen concentrations to make the diagnosis of PPHN is readily available but has limitations. Normal right arm oxygen levels with low oxygen levels taken from an umbilical artery or left arm/lower limb is the classic finding but may not be present if atrial right to left shunting is prominent. In addition the combination of patent ductus arteriosus with coarctation of the aorta may produce differential cyanosis, mimicking PPHN the clinical course of the disease and response to therapy may be the most useful diagnostic tool particularly where resources are limited

D. Investigation: In addition to conventional echocardiography, Doppler studies of ductal and tricuspid regurgitation in conjunction with simultaneous blood pressure measurements provide an accurate indication of right-sided cardiac pressures and physiology.

121

E. Management: The primary goal of therapy is to selectively reduce pulmonary vascular resistance and thereby improve oxygenation. In the level II nursery:

-

urgent echocardiogram (if available) to exclude cyanotic congenital heart disease (where Prostin may be life saving) oxygen warmth correction of hypoglycaemia and acidosis early consultation with NETS regarding: • need to transfer • diagnosis/differential diagnosis • level III management advice (see below)

Level III Management: Nitric oxide is the only specific therapy shown to reduce pulmonary vascular resistance. The reviewers for the Cochrane Library identified twelve RCTs evaluating the use of nitric oxide in term infants. They concluded "on the evidence presently available, it appears reasonable to use inhaled nitric oxide in an initial concentration of 20 parts per million for term and near term infants with hypoxic respiratory failure who do not have a diaphragmatic hernia". Other appropriate management strategies depend on the underlying disease process:

-

if surfactant deficiency is present, exogenous surfactant should be given. The use of exogenous surfactant in conditions characterised by surfactant inactivation eg meconium aspiration syndrome and pneumonia is less clear-cut but may be considered in individual cases high frequency ventilation is frequently used in PPHN. Maintaining a respiratory alkalosis may be useful but the association of low CO2 levels (e.g. < 30 mmHg) with poor neurodevelopmental outcome has resulted in a more cautious approach to this line of treatment judicious use of bicarbonate in conjunction with mild hypocapnia to maintain a pH of 7.4 to 7.5 is currently common practice muscle relaxation with pancuronium and liberal use of sedation (e.g. morphine) may assist in achieving adequate ventilation support of systemic blood pressure with inotropes such as dopamine and dobutamine (dose ranges from 5 - 20 mcg/kg/min) is useful in reducing right to left shunting other drugs such as tolazoline, and magnesium sulphate are less commonly used now than in previous years provision of liberal supplemental oxygen is beneficial. The risks of hyperoxia are much lower in the population of term infants compared with preterms

Once adequate oxygenation is achieved weaning of oxygen and other ventilator settings should be done in tiny increments to prevent a return to a fetal circulation pattern.

F. Areas of Uncertainty in Clinical Practice: - the management of diaphragmatic hernia remains controversial - nitric oxide and exogenous surfactant remain unproven therapies in this condition. - recent expert advice has tended towards an approach characterized by permissive hypercapnia and less aggressive oxygenation.

G. References: • •

Kinsella JP, Abman SH. Recent developments in the pathophysiology and treatment of persistent pulmonary hypertension of the newborn. J Pediatr 1995; 126:853-864. Finer NN, Barrington KJ. Nitric oxide for respiratory failure in infants born at or near term (Cochrane Review). Cochrane Database Syst Rev 1902; 4:CD000399

Other Reading/Web links: •

Zahka KG and Chandrakant RP. Cardiac problems of the neonate. In Fanaroff and Martin (eds) NeonatalPerinatal Medicine: diseases of the fetus and infant. 1997; 1161-1163.

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51. PNEUMOTHORAX DRAINAGE A. B. C. D. E.

Introduction Clinical Features Needle Aspiration Intercostal Catheter Insertion References

A. Introduction: Drainage of a Pneumothorax is often a matter of urgency especially when the air collection is under pressure. A pneumothorax diagnosed as an incidental finding on CXR may not require active drainage but when associated with clinical deterioration may require immediate drainage either by needle aspiration or intercostal catheter (ICC) insertion.

B. Clinical Features: - sudden deterioration with desaturation - increase in respiratory distress and/or diminished chest movements - circulation may become compromised - blood gases may show hypoxia, respiratory and/or metabolic acidosis. Clinical signs include: - unequal or decreased air entry - displaced apex beat - transillumination. This sign is unreliable in: • infants with increased thickness of the chest wall e.g. term infants and oedema • infants with pulmonary interstitial emphysema (who may show a 'false positive' result) CXR will confirm the diagnosis but takes time to perform.

C. Needle Aspiration: Needle aspiration is an emergency procedure only. Care must be taken to avoid laceration of the lung or puncturing blood vessels. Equipment: - 21gauge butterfly needle - 3 way stopcock - 10 ml syringe - 70% Isopropyl alcohol swab - 1 pair sterile gloves Procedure: - Infant supine, prepare area with alcohol wipe - Insert needle into the pleural space (directly over the top of the rib in the 2nd or 3rd intercostal space in the mid-clavicular line) until air is aspirated into the syringe, then expel air through the 3-way stopcock Ongoing Care: Following needle aspiration insertion of an intercostal catheter is required for on-going management. It may be necessary to seek help with this procedure -consultation and assistance will be available with the receiving NICU or NETS.

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D. Intercostal Catheter Insertion: Equipment: - Sterile surgical instrument pack - Size 11 scalpel blade - 3/0 black silk suture on a curved edge needle - Sterile gown, gloves and drapes - Skin preparation e.g. Betadine - Argyle 8, 10 or 12Fr sterile intercostal catheter - Elastoplast strapping - 1% Lignocaine, syringe and needle - Underwater seal drainage system or a Heimlich valve Procedure: - Observe universal precautions - Mask, sterile gown and gloves are required as for any sterile procedure - Place infant under radiant heater to maintain infant's temperature, try to maintain some area of the infant visible beyond the sterile field. Place the infant with the effected side uppermost and the arm extended above the head (a nappy cloth roll may help maintain a good position). Ensure limbs are adequately restrained. - Monitor infant's heart rate and oxygen saturation level - The intercostal catheter is inserted in the 4th or 5th intercostal space in the anterior axillary line. This corresponds to a point 1-2cm lateral to and 0.5-1cm below the nipple. The incision must be well clear of the nipple. - Prepare the field with iodine solution e.g. Betadine - Select intercostal catheter size

Infants

-

-

> 1500g

10 or 12Fr

< 1500g

8 or 10Fr

Place sterile drape in position Infiltrate the insertion site with 1% Lignocaine 0.5 - 1mL. (An alternate practice is to infiltrate with local anesthetic before preparing and draping the field in order to allow greater time for the anesthetic to take effect.) Using small (number 11) scalpel blade make a 1cm incision through the skin and subcutaneous tissue Using straight mosquito forceps to bluntly dissect away the subcutaneous tissue and intercostal muscles, the parietal pleura is reached. Aim to dissect a passage just above a rib border in order to avoid the neurovascular bundles running below each rib. Open the parietal pleura by blunt dissection. At this point the hiss of air escaping the pleural space may be heard Remove the trocar from the ICC and grasp the distal end with curved artery forceps. Advance the ICC into the pleural space 3 - 5cm, i.e. at the 1 - 3cm marking on the catheter directing the tip anteriorly as well as superomedially so that the tip lies beneath the anterior chest wall. Connect the ICC to a Heimlich valve or an underwater seal drainage system, and note whether the fluid is swinging and/or bubbling. Fogging within the catheter may be seen when within the pleural space. Place a single stitch through the wound so that the skin is drawn snugly around the ICC. Purse string stitches are not used as they leave an unsightly scar. Wrap the ends of the suture around the ICC several times and tie securely. Secure the ICC to the chest wall as shown in diagram. This helps to maintain the anterior position of the ICC and minimizes trauma to intrathoracic structures due to movement of the extrathoracic portion of the ICC.

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Ongoing Care:

-

Check the tube position and resolution of the pneumothorax by transillumination and x-ray as soon as possible. The need for ongoing analgesia is based on an assessment of physiological and behavioural responses associated with pain. Infants requiring an intercostal catheter should be transferred to an NICU as soon as possible for ongoing care.

References: •

Stabilization and Transport of Newborn Infants and At-Risk Pregnancies. Editors ED Bowman, SM Levi, FE Presbury, A McLean. Newborn Emergency Transport Service, 4th Edition,1998.

52. POLYCYTHAEMIA A. B. C. D. E. F.

Introduction Causes Investigation Management Areas of Uncertainty in Clinical Practice References

A. Introduction: Polycythaemia is defined as a venous haematocrit greater than 65% and occurs in 0.4 - 4% of newborn infants. This may result in increased blood viscosity and therefore reduced blood flow, impaired tissue oxygenation and a tendency to microthrombus formation exacerbated by hypoxia, acidosis and/or poor perfusion. Thrombosis may result in renal venous thrombosis, adrenal insufficiency, necrotising enterocolitis and cerebral infarction that may affect long-term neurological outcome.

B. Causes: Although most cases of polycythaemia occur in normal healthy infants, polycythaemia may result from:

-

-

placental red cell transfusion (delayed cord clamping, twin to twin transfusion syndrome) placental insufficiency with increased fetal erythropoiesis secondary to intra-uterine hypoxia • small for gestational age infants • pre-eclampsia • postmature infants other: • maternal diabetes • large for gestational age infant • chromosomal (e.g. Down Syndrome)

Many polycythaemic infants are asymptomatic. When present, the signs and symptoms of polycythaemia are nonspecific and include:

-

feeding problems plethora lethargy cyanosis respiratory distress jitteriness hypotonia hypoglycaemia jaundice hypocalcaemia thrombocytopenia

C. Investigation: The diagnosis of polycythaemia is made on central or peripheral venous blood with a haematocrit over 65%. Because capillary blood haematocrit is not reliable, a peripheral venous haematocrit should be performed if the capillary haematocrit is above 65%. The haematocrit peaks at 2 hours of age, then falls by 6 hours of age and thereafter.

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D. Management: - universal screening of haematocrit for polycythaemia is not warranted. Many selectively test for -

polycythaemia in high-risk infants (e.g. IDM, placental insufficiency) treatment of polycythaemia is with liberal fluid intake and/or partial exchange transfusion (PET) to reduce the venous haematocrit below 60%. Asymptomatic polycythaemic infants should have their fluid intake liberalized. PET using Normal Saline as the replacement fluid is recommended in symptomatic infants with a haematocrit above 65%

Volume of exchange (ml) = blood volume*(observed - desired haematocrit)/ observed haematocrit *Term blood volume is 85 ml/kg This is best performed through peripheral arterial and venous lines.

E. Areas of Uncertainty in Clinical Practice: Treatment of polycythaemia with PET is controversial. Whilst it may improve symptoms, there is inconclusive evidence that it improves long-term outcome in either asymptomatic or symptomatic polycythaemic infants. In spite of inconclusive evidence, some still advocate PET when the venous haematocrit is above 70% in asymptomatic infants.

F. References: • • • •

American Academy of Pediatrics Committee on Fetus and Newborn. Routine Evaluation of blood pressure, hematocrit and glucose in newborns. Pediatrics 1993;92:474-6 Werner EJ. Neonatal polycythemia and hyperviscosity. Clinics in Perinatology 1995;22:693-710. Wiswell TE, Cornish JD, Northam RS. Neonatal polycythemia: frequency of clinical manifestations and other associated findings. Pediatrics 1986;78:26-30 Wong W, Fok T, Lee CH et al. Randomised controlled trial: comparison of colloid or crystalloid for partial exchange transfusion for treatment of neonatal polycythemia. Arch Dis Child 1997;77:F115-8

53. RESPIRATORY DISTRESS SYNDROME (RDS) A. B. C. D. E. F. G. H.

Summary Introduction Differential Diagnosis Investigations Management Sudden deterioration Areas of Uncertainty in Clinical Practice References

A. Summary: - attention to thermoregulation and oxygenation can decrease the severity of RDS - antibiotics are usually indicated for infants with respiratory distress - level of experience and expertise dictate what technical procedures (IV and ETT insertion) are indicated -

prior to arrival of the transport team surfactant administration should follow as soon after endotracheal intubation as possible infants requiring more than 60% oxygen should be managed in a tertiary centre

B. Introduction: Respiratory distress syndrome (RDS), also known as Hyaline Membrane Disease (HMD), is the dominant clinical problem faced by preterm infants. The greatest risk factor is low gestational age and the development of the disease begins with the impaired synthesis of pulmonary surfactant associated with prematurity. The disease is exacerbated by treatable/preventable factors including: - cold stress - hypoxia - acidosis The diagnosis is made on the basis of the combination of clinical (grunting respirations, intercostals recession, nasal flaring, cyanosis and increased oxygen requirement) and radiological (diffuse reticulogranular pattern with air bronchograms) features. The natural history is for the clinical signs to develop within 6 hours of life, with progressive worsening over the first 48 to 72 hours of life followed by recovery. The condition can be prevented or the severity diminished by antenatal administration of betamethasone. The course of the disease is altered by exogenous surfactant therapy and assisted ventilation.

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C. Differential Diagnosis: Signs and radiolological appearance of RDS are not specific and other causes of respiratory distress should be considered. In particular it is difficult to exclude sepsis as a possible diagnosis initially and antibiotic therapy should be given until blood cultures prove negative. "Wet lung" and lung malformations as well as non-pulmonary causes of respiratory distress are uncommon in the preterm infant but should be excluded using the appropriate tests.

D. Investigation: A chest xray is useful and should be performed in all cases of respiratory distress once the oxygen requirement exceeds 30%. The X-ray may need to be repeated if the illness runs a course that is unusual or protracted or the infant’s status suddenly worsens when air leak complications must be considered. A full blood count and blood culture should be performed prior to starting antibiotics but antibiotics should not be withheld if blood sampling proves technically difficult. Antibiotics may be given intramuscularly in these circumstances.

E. Management: 1. Nonrespiratory:

-

-

temperature control is an important facet of the care of the infant with respiratory distress and both hypo and hyperthermia should be avoided. The temperature should be maintained in the neutral thermal range enteral feeding should generally be avoided in infants with significant respiratory distress (oxygen requirements greater than 35%). During the initial stabilisation intravenous fluid therapy is useful if it can be started easily but premature infants do not necessarily require an IV immediately. Exposure to manipulation and cold stress may do more harm than good in this situation. Attention to prevention of hypoglycemia is, however, an important part of on-going care minimal handling is important. This can be facilitated by the use of monitors to help assess infant status (cardiorespiratory, temperature and oxygen saturation monitiors should be used whenever possible) antibiotics — commence penicillin and gentamicin therapy after initial investigations

2. Respiratory: 2.1. Airway: Placing the infant in the lateral or prone posture rather than supine provides a clear airway. Repeated suctioning of the pharynx is not required and may cause apnoea and hypoxia. 2.2. Oxygen: Although both too much and too little oxygen are bad for preterm infants, hypoxia is much more dangerous over the short period of time while awaiting transport. 2.2.1. Monitoring: Arterial blood gases — accurate assessments can be made from samples taken from indwelling arterial lines which are usually performed in an intensive care setting, aiming to keep pO2 between 50 and 80 mm Hg. Assessment of oxygen requirements from arterial ‘stabs’ is not reliable. Non-invasive monitoring — oxygen saturation monitors may be attached to the infant’s hand or foot. The desired range for infants less than 34 weeks gestation is 88 to 95% and for more mature infants 88 to 100%. Cyanotic threshold — keep the ambient oxygen concentration 5 to 10% above the level at which the infant is noted to be cyanosed. 2.2.2. Administration: Oxygen concentrations up to 40% may be achieved through the oxygen port into an incubator. Above 40% is best achieved using warmed, humidified gas delivered via a headbox. Flow rates of at least 6-8 l/min are required to avoid rebreathing.

3. Intubation and intermittent positive pressure ventilation (IPPV): Indications: - cyanosis that persists in spite of maximal oxygen therapy - severe recurrent apnoea - respiratory failure (pCO2 > 70 and pH < 7.2) See Intubation Procedure section for further details. Stabilization ventilator settings For an infant with RDS reasonable settings are: ventilator rate 60 breaths per minute, inspiratory time 0.3 sec (expiratory time 0.7 sec), PEEP 5 cm and oxygen set to maintain saturations of 88 to 95%. Peak inspiratory pressure (PIP) should be set to achieve "reasonable" chest movement — usual intial settings in RDS will lie between 20 and 30 cm water. Surfactant administration should be considered in any intubated infant with a presumed diagnosis of RDS.

127

F. Sudden deterioration: In a spontaneously ventilating infant sudden deterioration may be caused by:

-

pneumothorax failure of oxygen supply increase in severity of the underlying disease

Infants may be able to sustain the protracted tachypnoea associated with RDS for hours or days before developing respiratory failure. This may be signalled by onset of apnoea, sudden increase in oxygen requirements or very laboured respiratory efforts. Continued close monitoring throughout the infan's entire illness is mandatory. In a ventilated infant sudden deterioration is most likely to be caused by:

-

pneumothorax (easily overlooked clinically so transillumination or a further chest X-Ray are essential.) endotracheal tube blockage or displacement mechanical failure with the ventilator increase in the severity of the underlying lung disease massive intraventricular haemorrhage necrotizing enterocolitis, especially if perforation has occurred patent ductus arterious

G. Areas of Uncertainty in Clinical Practice: NCPAP vs endotracheal intubation and surfactant for infants with RDS.

H. References: • •

Stabilization and transport of newborn infants and at-risk pregnancies 4th Edition 1998 NETS Publication Neonatal-perinatal medicine: Diseases of the fetus and infant 6th ed 1997. Fanaroff AA and Martin RJ (eds). Mosby-Year Book.

Other Reading/Web links: •

• • • •

The following reviews published in the Cochrane Library provide more detail on the evidence underlying: - use of exogenous surfactant in RDS - choice of exogenous surfactant - timing of surfactant therapy - choice of ventilator rate Greenough A, Milner AD, Dimitriou G. Synchronized mechanical ventilation for respiratory support in newborn infants (Cochrane Review). In: The Cochrane Library, Issue 2, 2001. Oxford: Update Software. Soll RF. Synthetic surfactant for respiratory distress syndrome in preterm infants (Cochrane Review). In: The Cochrane Library, Issue 2, 2001. Oxford: Update Software. Soll RF, Blanco F. Natural surfactant extract versus synthetic surfactant for neonatal respiratory distress syndrome (Cochrane Review). In: The Cochrane Library, Issue 2, 2001. Oxford: Update Software. Yost CC, Soll RF. Early versus delayed selective surfactant treatment for neonatal respiratory distress syndrome (Cochrane Review). In: The Cochrane Library, Issue 2, 2001. Oxford: Update Software.

54. RESUSCITATION A. B. C. D. E. F. G. H.

Summary Introduction Preparation Assessment Management Stopping Resuscitation Areas of Uncertainty in Clinical Practice References

A. Summary: -

newborn resuscitation is a critical skill that requires constant practice organisation is the key to successful resuscitation evaluation and resuscitation interventions are ongoing, continuous and simultaneous processes

128

B. Introduction: Approximately 1 - 10% of in hospital delivered newborns require resuscitation. The aim of resuscitation is to prevent neonatal death and adverse long term neurodevelopmental sequelae associated with birth asphyxia. Substantial physiologic changes occur in the transition from fetal to extrauterine life including:

-

changes from fluid-filled to air filled alveolar sacs reduction in pulmonary vascular bed pressure reduction of intra and extra cardiac shunting establishment of adequate lung volume (FRC) surfactant production

Failure or disruption of these changes may result in further difficulties with resuscitation in the newborn infant. For example, failure to increase alveolar oxygen and reduce pulmonary vascular resistance may lead to persistence of fetal circulation or pulmonary hypertension. Low critical mixed venous saturation with hypoxic hypoxia underscores the importance of cardiac output to oxygen delivery. The cyanosed infant with cardiac output (hypoxic hypoxia) is more able to withstand hypoxia than the infant with cardiac standstill (stagnant hypoxia) because of the physiologic manoeuvres incorporated into the response to hypoxia. Compared with adults, CO as a proportion of weight is high in newborns. They have limited capabilities to increase cardiac output particularly in response to increases in afterload. Hypovolaemic anaemia is poorly tolerated in the newborn. The phases of asphyxia are well described from experimental evidence in animal models.

-

After a few shallow breaths the asphyxiated infant stops breathing. This phase of primary apnoea may last for as long as 10 minutes. Most infants with primary apnoea respond to stimulation alone. During this phase heart rate and pH are maintained. Following this period, the infant begins to gasp. The period between the last gasp and cardiac arrest is secondary apnoea. In the phase of secondary or terminal apnoea the newborn has a mixed acidosis and active intervention is required to stimulate respiration.

It is not possible to clinically distinguish primary from secondary apnoea and for this reason it is important to assume the apnoiec infant is in secondary apnoea. If there is no response to simple interventions the infant requires the immediate commencement of active resuscitation.

C. Preparation: -

Personnel: • at least two trained people are required for adequate resuscitation involving ventilation and cardiac compressions. Therefore, always call for help • the most senior person available needs to co-ordinate resuscitation • each person must have a dedicated job, for example with three people, one should be solely responsible for airway, one solely responsible for chest compressions and the third person should co-ordinate the resuscitation and administer medication as necessary. If possible have another person record events including time of administration of drugs, HR response.

-

Check equipment: • resuscitaion equipment should be checked at least daily and after each usage • when use is anticipated at a birth recheck equipment. Including oxygen supply, suction, bag and mask circuit, largyngoscope, and endotracheal tubes. If an infant is expected to be in poor condition have medication readily available

-

Communication is vital to smooth resuscitation: • with anaesthetic and obstetric staff regarding maternal condition, fetal condition, maternal therapies • if time permits, meet the family before delivery

-

Environment: • prevention of heat loss is important • where possible deliver infant into a warm draft free environment • dry infant, remove wet toweling and replace with dry, warm towels

129

D. Assessment: The steps of evaluation and intervention are often simultaneous processes. Evaluation begins immediately after birth and continues throughout the resuscitation process until vital signs have normalized. Key features to evaluate are: - Respiration: The newly born infant should establish regular respirations in order to maintain HR > 100 bpm - Heart Rate: Determined from direct palpation of cord, apex beat or with stethoscope. Peripheral pulses are often difficult to feel If no pulsation is felt on palpation of the cord do not assume there is no heart beat but auscultate the chest.The HR should be > 100 bpm in a well newly born infant - Colour: The well newly born infant should be able to maintain a central pink colour in room air

E. Management: -

Stimulation: Most infants respond to stimulation with movement of extremities. Appropriate stimulation includes drying the face or flicking the bottom of the feet. If meconium is present in a non-vigorous infant suction under direct vision. Delay tactile stimulation to avoid gasping in the infant with an oropharynx full of particulate meconium.

-

Airway: The head should be in a neutral or slightly extended 'sniffing' position. Suction should not exceed -100 mmHg. It should be limited in depth to 5 cm below the lips.

-

Breathing: Attend to adequate inflation and ventilation before oxygenation The rate for assisted ventilation is 60 bpm Tidal volume is assessed clinically, that is adequate chest excursion with each breath Few infants require immediate intubation. The majority of infants can be managed with bag and mask ventilation. See intubation section for technical details

-

Circulation: In the majority of infants establishment of adequate ventilation will restore circulation. Begin chest compressions for either: • absent HR or HR < 60 for 30 seconds. • Aim for approximately a ratio of 90 chest compressions to 30 breaths per minute (3:1). (120 events per minute) - count one-and-two-and-three-and-breath etc • The "two thumb" technique is preferred. Both thumbs meet over the sternum with fingers around the chest wall. The sternum should be compressed to one third of the antero-posterior chest dimension. Medications:

•

• • • •

Route of Delivery: - umbilical venous catheter - ET - for either adrenaline or naloxone - peripheral intravenous line - difficult to cannulate in the collapsed infant - umbilical arterial catheter should not be used for vasoactive substance and is not rapidly accessible Adrenaline: For HR < 60 for > 30 sec despite compressions Dosage: 0.1 - 0.3 mls/kg 1 in 10,000 repeated at 3-5 minutely intervals Volume (preload): 10 - 15 ml/kg normal saline repeated 2 or 3 times Naloxone: Dosage - 0.1ml/kg of 0.4mg/ml solution Contra-indication - infants of narcotic dependent mothers, may result in rapid withdrawal with seizures Bicarbonate: Currently there is insufficient evidence for routine use Argument for correction of acidosis includes theoretical concerns about hypoxia and elevated pulmonary vascular bed pressure and poor cardiac contractility with acidosis. Argument against correction includes concerns regarding hyperosmolarity and CO2 generation with intracellular acidosis from alkali infusion.

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F. Stopping Resuscitation: -

it is difficult to accurately define a time beyond which active support worsens brain injury it is reasonable to consider stopping treatment if the infant has not responded with a spontaneous circulation by 15 minutes of age it is helpful to be able to review events during resuscitation and this is made easier when events are recorded during resuscitation

G. Areas of Uncertainty in Clinical Practice: -

Recent animal studies suggest that cerebral hypothermia may be beneficial to the asphyxiated infant. There is not enough current evidence to recommend this practice for routine care. This should only be undertaken in the context of a properly controlled trial There is little available literature regarding the value of air versus oxygen for resuscitation. Current recommendations (ILCOR) include the use of 100% oxygen. Theoretically, by its effect on lung volume PEEP preserves surfactant function. PEEP sets up FRC and is therefore important in ventilation and oxygenation. It is possible to provide PEEP during the acute either by use of either an anesthetic bag and mask (considerable practice is required to develop competence with this technique) or the Neopuff (this technique can be easily applied but the device will require a flow of gas to operate).

H. References: • • • • • • • • •

Cooling the newborn after Asphyxia - physiologic and experimental background and its clinical use. Thoresen M Semin Neonatol 2000 Feb;5(1):61-73 Rapid correction of early metabolic acidosis versus placebo, no intervention or slow correction in LBW infants. Kecskes Z, Davies MW Cochrane Database of Systematic Reviews. Issue 1, 2001 Air versus oxygen for resuscitation of infants at birth. Tan A, Schulze A, Davis PG Cochrane Database of Systematic Reviews. Issue 1, 2001 Tidal ventilation at low airway pressures can augment lung injury. Muscedere JG etal. Am J Respir Crit Care Med. 1994 May;149(5):1327-34 Ventilator-induced lung injury: lessons from experimental studies. Dreyfuss D, Saumon G. Am J Respir Crit Care Med. 1998 Jan;157(1):294-323 The open lung during small tidal volume ventilation: concepts of recruitment and "optimal" positive endexpiratory pressure Rimensberger PC, Cox PN, Frndova H, Bryan AC. Crit Care Med 1999;27:1946-52 Cardiopulmonary resuscitation of apparently stillborn infants: survival and long-term outcome. Jain L, Ferre C, Vidyasagar D, Nath S, Sheftel D. J Pediatr. 1991 May;118(5):778-82. Survival after cardiopulmonary resuscitation in babies of very low birth weight. Is CPR futile therapy? Lantos JD, miles Sh, Silverstein MD, Stocking CB N Engl J Med. 1988 Jan 14;318(2):91-5. Outcome of resuscitation following unexpected apparent stillbirth. Casalaz DM, Marlow N, Speidel BD. Arch Dis Child Fetal Neonatal Ed. 1998 Mar;78(2):F112-5. Outcome of resuscitated apparently stillborn infants: a ten year review. Yeo Cl, Tudehope DI. J Paediatr Child Health. 1994 Apr;30(2):129-33

55. RETINOPATHY OF PREMATURITY A. B. C. D. E. F. G. H. I.

Summary Introduction Pathogenesis Classification of ROP Incidence Treatment Screening Areas of Uncertainty References

A. Summary: -

the median onset of threshold disease (that requiring intervention) is 36 - 37 weeks corrected age - babies must continue ophthalmological followup until there is mature vascularisation of the retina (at least term) treatment of threshold disease reduces the incidence of retinal detachment by 50% whether or not treatment is required, babies with ROP are at increased risk of ophthalmological problems

131

B. Introduction: Retinopathy of prematurity (ROP) is an abnormal vascular proliferative disorder of the immature retina that may acutely threaten vision. In the longer term, even after regression, it can lead to: - acuity defects - refractive errors - gaze abnormalities As such it has life-long implications for nursery graduates.

C. Pathogenesis: Normally, the nasal and temporal retina is vascularised, to the ora serrata, by 36 and 40 weeks respectively. Damage to the developing retinal capillaries delays vascularisation. Once the developing vessels have been damaged, it is hypothesised that the retina responds with the production of growth factors stimulating neovascularisation, which is the observable retinopathy. This may result in either successful revascularisation of the retina or progression to neovascular membranes in the vitreous and subsequent scarring and retinal detachment.

D. Classification of ROP: Following a series of consensus meetings in 1984, ROP was newly classified according to: - location (zone) - see Figure 1 - extent (clock hours of disease) - severity (stage) - see Table 1 - the presence or absence of plus disease, (vascular decompensation manifest as vessel dilatation and tortuosity)

Fig 1. ICROP zone Scheme for locating ROP ( courtesey of Arch Ophthalmo! 1984; 102:1130-4). Table 1 - Staging of ROP:

Stage 1 - distinct white line or demarcation line between vascular and avascular retina, often with abnormal branching of vessels leading to it Stage 2 - heaping up of abnormal pink to salmon coloured tissue in the region of the demarcation line that appears to have depth when compared to the smooth surface of the retina Stage 3 - fine vessels appear along the surface of the ridge to just posterior to it and the fibrovascular proliferation invades the vitreous Stage 4 - partial retinal detachment Stage 5 - total retinal detachment

132

"Threshold" ROP, is a prognostically relevant level of disease severity at which the risk of blindness in untreated eyes is greater than 47%. Premature infants can be categorised as:

No ROP

ROP never seen on any examination

Prethreshold ROP Zone 1 ROP of any stage less than threshold; zone 2 ROP at stage 2+; zone 2 ROP stage 3 without plus; zone 2 ROP stage 3+ with fewer than the threshold number of sectors of stage 3+ Threshold ROP

Five or more contiguous or eight cumulative clock hours (30o sectors) of stage 3+ ROP in either zone 1 or 2

E. Incidence: The Natural History Cohort Study (The Cryotherapy for Retinopathy of Prematurity Cooperative Group) included 4099 infants less than 1251 grams at 23 centres in USA between January 1986 and November 1987. Initial ophthalmic examination was performed at 4 to 6 weeks of age with subsequent examinations at 2 weekly intervals until the retina became fully vascularised. Overall 65.8% of infants developed ROP: - stage 1 - 25.2% - stage 2 - 21.7% - stage 3 - 18.3% 2237 infants were less than 1000 grams: - 81% of these developed some ROP - 9.3% developed threshold disease with respect to demographic factors: - there was a racial difference (favoring African-Americans) there was no difference in: - gender - plurality - site The median onset of threshold ROP was between the 36th and 37th week post-conceptual age (33.6[5th%] 42.0[95th%] weeks) (see diagram).

F. Treatment: Treatment of established "threshold" disease was introduced in order to prevent the high risk of blindness in affected eyes. This involved ablation of the peripheral avascular retina, thus preserving central macula vision. Treatment modalities include: - transscleral cryoablation (technically easier in infants with hazy vitreous) - photocoagulation (laser) - cryoablation

133

These interventions aim to destroy the avascular retina thought to be responsible for the angiogenic growth factors that drive the neovascularisation. Peripheral retinal ablation, by any means, reduces the incidence of early adverse ophthalmic outcome (retinal detachment) in infants with threshold ROP by 50% (from 47.9 to 28.1%). It is important to note that the risk of blindness in treated eyes remains (though the risk is halved) even after intervention. The risk of retinal detachment in treated eyes remains stable whereas the risk of detachment continues in untreated eyes with threshold disease. Cryotherapy may produces a small reduction in the visual field.

G. Screening: The aim of screening is to identify those infants at risk of vision threatening retinopathy so as to allow effective therapy to prevent poor ophthalmic outcomes (blindness). In Victoria, screening occurs in babies <1250g who have received supplemental oxygen. The retinas are checked by an experienced paediatric ophthalmologist at 4-6 weeks of age, with the subsequent frequency depending on the location, extent and severity of the disease. A more detailed screening plan is outlined in the American Academy of Pediatrics position statement.

H. Areas of Uncertainty: -

a comparison of the effectiveness of laser vs cryoablation in the setting of threshold ROP is currently being undertaken

I. References: • •

American Academy of Pediatrics. Screening examination of premature infants for retinopathy of prematurity. Pediatrics 2001;108:809-811 Lee SK, Normand C, McMillan D et al. Evidence for changing guidelines for routine screening for retinopathy of prematurity. Arch Pediatr Adolesc Med 2001;155:387-95

56. SMALL FOR GESTATIONAL AGE INFANTS A. B. C. D. E. F. G. H. I.

Definition Types Aetiology Physical Examination Problems in SGA Investigations Management Outcome References

A. Definition: Small for gestational age infants are defined as having a birth weight more than 2SD below the mean or less than the 10th percentile of a population specific weight versus gestational age plot.

B. Types: Symmetric: Weight, head circumference and length all below the 10th percentile. Brain growth may be limited.

Causes

intrinsic fetal causes intrauterine infection severe placental insufficiency constitutionally small infant

Asymmetric: Weight below the 10th percentile but head circumference and length relatively preserved. Brain growth relatively spared.

Causes

interference with placental function or maternal health in 3rd trimester.

Infants whose weight is greater than the 10th percentile but who are thin relative to their length and head circumference are at similar risk of neonatal complications as SGA infants. They should be considered "relatively" SGA (Clifford syndrome). The weight/length ratio (or the Ponderal Index = [weight (g)]/[length (cm)]3 ) is less than normal for such infants. However, unless great care is taken with the measurement of length the calculated index can be misleading.

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C. Aetiology: Fetal

-

chromosome disorders (eg Trisomy 21, Trisomy 18) chronic fetal infection (eg CMV, Rubella, Syphilis, Toxoplasmosis) congenital malformations: including congenital heart disease, diaphragmatic hernia, tracheo-oesophageal fistula syndrome complex radiation multiple gestation relates more to placental limitation rather than intrinsic baby problem

Mother

-

pregnancy induced hypertension hypertension or renal disease or both hypoxaemia (high altitude, cyanotic cardiac or pulmonary disease) malnutrition or chronic illness drugs (narcotics, alcohol, cigarettes, cocaine, antimetabolites)

Placental

-

decreased placental weight or cellularity or both decrease in surface area, infarction villous placentitis (bacterial, viral, parasitic) tumour (chorioangioma, hydatiform mole) placental separation twin to twin transfusion syndrome

Constitutional -

familial and racial background

D. Physical Examination: Physical examination of the SGA infant must include a detailed search for associated abnormalities. - dysmorphic features "unusual" facies: • abnormal hands and feet • abnormal palmar creases • in addition to gross anomalies - ocular disorders, such as: • cataracts • cloudy cornea • chorioretinitis - features of intrauterine infection: • hepatosplenomegaly • jaundice • blueberry-muffin rash

E. Problems in SGA: Problem

Pathogenesis

Intrauterine fetal demise

Hypoxia, acidosis, infection and lethal anomaly

Perinatal asphyxia

Decreased uteroplacental perfusion in labour chronic fetal hypoxia-acidosis

Hypoglycemia

Decreased tissue glycogen stores, decreased gluconeogenesis and high glucose requirements

Polycythemia hyperviscosity

fetal hypoxia with increased erythropoietin production

Hypothermia

Large surface area, poor subcutaneous fat stores

Respiratory distress

intrauterine pneumonia, meconium aspiration syndrome, PPHN

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F. Investigations: Investigations are required to: - screen for hypoglycemia - assess the infant according to clinical signs: • polycythemia and hypocalcaemia are more common. • if respiratory distress present, ABG and Chest X-ray. - establish the cause of growth restriction: • intrauterine infection suspected; check maternal TORCH serology and screen infant urine and saliva for CMV (further investigation will be required if suspicion confirmed). • if dysmorphic; genetic consultation and chromosome studies • if showing signs of withdrawal urine for drug screen. • ultrasonography and echocardiography, if clinically indicated

G. Management: 1.

At Delivery: Place promptly under a radiant warmer and dry. Infants with severe SGA, particularly in association with fetal distress, are at risk of aspiration of meconium , hypoxaemia, hypotension, mixed metabolic and respiratory acidosis and persistent pulmonary hypertension.

2.

Hypothermia: Nurse in a thermoneutral environment

3.

Hypoglycemia: Monitor blood glucose and commence early enteral feeds or intravenous glucose infusion.

4.

Necrotisingenterocolitis: Infants, particularly preterm SGA, found to have placental insufficiency and abnormal umbilical artery Doppler studies may be at particular risk of developing NEC or gastrointestinal perforation. Enteral feeding should be increased gradually.

5.

Polycythemia: Partial volume exchange may be required for symptomatic infants.

H. Outcome: Principally determined by the cause. 1.

Postnatal physical growth:

Symmetric SGA - smaller and relatively under weight throughout life. Asymmetric SGA - accelerated velocity of growth ("catch up growth") in first 6 months and normal development. 2.

Neurodevelopmental outcome:

Term SGA - no increase risk of severe neurologic morbidity compared to term AGA infants. However increased hyperactivity, short attention span and learning problems Preterm SGA - Minor neurologic abnormalities more common than in preterm AGA infants.

I. References: • • •

Avery GB, Fletcher MA, MacDonald MG, eds. Neonatology. 5th ed. Philadelphia, Pa: Lippincott Williams & Wilkins, 1999:411-444. Rennie JM, Roberton NRC (Eds). Textbook of Neonatology, 3rd edition. Churchill Livingstone , Edinburgh, 1999. Patti J Thureen, Marianne S Anderson and William W. Hay, Jr. Small for gestational age, NeoReviews; 2001; E139-e149.

Web Links: •

www.neoreviews.aapjournals.org

57. SHOCK A. B. C. D.

Aetiology Blood Pressure Management of Shock Management of Secondary Complications

Shock is a complex syndrome of circulatory dysfunction associated with reduced oxygen and nutrient delivery to peripheral and ultimately to central organs. The aetiology is multifactorial and the syndrome is frequently complicated by secondary involvement of many organ systems. The major secondary complication of severe shock, virtually universal in fatal shock, is a syndrome characterised as Systemic Inflammatory Response Syndrome (SIRS).

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The key features of SIRS are: - circulatory failure - endothelial dysfunction - organ failure - coagulation disturbances These secondary phenomena are responsible for much of the mortality and morbidity and early recognition and aggressive management are essentials of successful management.

A. Aetiology: Hypovolaemia Relative

Vasodilatation Third space losses

Absolute

Blood loss Intracranial Haemorrhage Diuresis Insensible loss

Cardiogenic Obstructive lesions Myocardial

Aortic stenosis Coarctation SIRS Hypoplastic Left Heart Cardiomyopathy Myocarditis Hypoxic-Ischaemic injury

Arrhythmia Other

Cardiac Tamponade Tension pneumothorax Air embolism

Septic Viral Bacterial Fungal Likely clinical contexts:

-

feto-maternal haemorrhage vasa praevia cord accidents/acute bleeding perinatal asphyxia ELBW infant chorioamnionitis severe sepsis high fluid losses assisted ventilation (iatrogenic problems)

Clinical features of shock:

-

hypotension peripheral vasoconstriction tachycardia (sometimes only bradycardia in ELBW) tachypnoea hypoxia metabolic acidosis CNS disturbance (lethargy, irritability) oliguria

B. Blood Pressure: It is difficult to state meaningfully what a satisfactory blood pressure is in the context of the seriously ill infants for whom this is relevant in treatment. 'Normal' values may not necessarily be helpful in defining a level of blood pressure below which the infant is compromised. Careful clinical judgement is important.

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The levels below are based on the best available evidence, but are probably higher than the level at which the infant is compromised. It is important to avoid over treatment and the lower end of these ranges should be used to guide treatment decisions. The basic goal should be an infant with good clinical perfusion and pulses, normal neurological behaviour, urine output of >0.5ml/kg/hr and no metabolic acidosis or lactate accumulation. 'Normal' Ranges See Blood Pressure tables

C. Management of Shock: Prevention, early diagnosis and aggressive management are the cornerstones of care. Once the secondary complications of shock (SIRS etc.) are established it is very difficult to reverse shock. The key goal is the establishment of adequate tissue perfusion and oxygenation. Early consultation with NETS/ Level 3 centre is important once shock is diagnosed.

-

• • •

-

-

Establish airway, breathing, circulation: sick, clinically shocked neonates should be intubated and ventilated before they meet conventional ventilation criteria if this can be achieved safely (consider experience of operator). Intubation may precipitate decompensation in the critically ill child. perform once circulation stabilised, especially if using induction agents. if using vasodilating agents (e.g. opiates), volume load first Stop any bleeding Monitor oxygen saturations. Administer oxygen as needed Establish reliable intravenous access: • Peripheral IV - do not waste time on peripheral IV if proving difficult • If peripheral access is difficult to achieve ƒ Umbilical Venous catheter (5F for preterm, 5 - 8 F for term or 5 - 8F sterile feeding tube) ƒ Intraosseous Consider and treat cause (including iatrogenic problems) • screen for sepsis • cover with broad spectrum antibiotics:

Early onset <48 hrs)

Late onset (>48 hrs) - Level 2 or has been home Late onset (>48 hrs) - Level 3

• •

-

• • •

-

• • •

Penicillin 60 mg/kg IV 12 hrly Gentamicin 2.5 mg/kg stat, subsequent dosing according to weight and renal function Flucloxacillin 50 mg/kg/6 - 8 hrly Gentamicin 2.5 mg/kg, subsequent dosing according to weight and renal function Vancomycin 15 - 20 mg/kg Gentamicin 2.5 mg/kg, subsequent dosing according to weight and renal function

consider Herpes and need for acyclovir consider use of Immunoglobulin (Intragam) in established sepsis exclude: pneumothorax pericardial tamponade occult bleeding

Ensure adequate volume replacement: administer 10 - 20 mls/kg N Saline. Repeat according to response if clinical evidence of major blood or fluid loss, use appropriate higher volumes severe sepsis may require 40-60 mls/kg to establish adequate blood volume

There is no evidence that colloid has any advantage over saline in initial resuscitation If blood loss, use blood early. Initially packed cells: - urgently Cross matched if available in time - O Negative. Low titre. Uncrosssmatched - placental blood (Heparinised syringe. Sterilise placental surface vein with alcohol. Use clot filter) Once initially stabilised consider need for other blood products: - Fresh Frozen Plasma - platelets

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These should be given on the basis of active bleeding or significant abnormality on investigation. - Consider treatment of acidosis: Primary goal is establishment of stable circulation, perfusion and ventilation Once these are addressed and CO2 is normal, if metabolic acidosis is present, correct acidosis using Sodium Bicarbonate (dose (mmol) = BE *wt/4)

-

Inotropes:

Dobutamine

10 - 20 microgram/kg/min +/- Dopamine 2 microgram/kg/min (for Dopaminergic renal effect)

Or Dopamine

10 - 20 microgram/kg/min

Dobutamine

raises cardiac output causes some peripheral vasodilatation not as efficient at raising BP as dopamine safer via peripheral IV infusion

Dopamine

raises BP more small or negligible increase in cardiac output

Choice conditioned by physiology and immediate goals of treatment.

-

• • • •

If response poor: check diagnosis transilluminate chest establish that ventilation and airway remain intact consider adequacy of volume replacement

Consider Adrenaline infusion (0.05 - 1.0 microgram/kg/min) : • consider use of steroids • especially in ELBW infants • dose: Hydrocortisone 3mg/kg 6 hourly - noradrenaline should only be used in an ICU setting: - a poor response to inotrope therapy can be due to an acquired catecholamine resistance. This is most commonly a problem in overwhelming sepsis or in the chronically hypoxically stressed or failing myocardium. Dopamine and Dobutamine will not work well in this situation. Early use of Adrenaline is advisable and urgent discussion with a Level 3 Consultant should be undertaken.

D. Management of Secondary Complications: a) Respiratory:

• Early stabilisation of airway breathing and circulation has been dealt with above • Ongoing ventilatory problems are commonly a feature of the sicker infant. Pulmonary oedema, hyaline membrane disease, ARDS and pneumonia may all be associated and need to be considered and treated in their own right. • The combination of poor myocardial and circulatory performance with endothelial dysfunction commonly complicates respiratory management. End pressures used in ventilation should probably be higher because of this (6-8 cm) and careful attention needs to be paid to circulation. • The early ventilatory stabilisation of a critically ill patient may be associated with some understandable overaggression, with the attendant risk of complications. It is important to reassess treatment quickly once stable to ensure that treatment is adequate but not excessive. Excessively low carbon dioxide levels are particularly to be avoided because of concerns about CNS injury (especially in conjunction with sepsis). • Ventilatory stabilisation should be undertaken on the advice of the NETS consultant. These guidelines are given as a starting point:

Goals: pH

7.2 - 7.35

CO2

40 – 55

O2

50-70

Base Deficit better than negative 8.00 Saturations 85-95%

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b) Renal: Renal impairment is a significant component of most shock syndromes in the neonate. Oliguria is the rule and may be associated with acute tubular necrosis or acute cortical necrosis. Complications include hyperkalaemia and fluid overload. If urine output is below 0.5 ml/kg/hr manage by: - volume loading 10ml/kg - frusemide 2mg/kg - low dose dopamine at 2-5 microgram/kg/min The ELBW infant with renal impairment is particularly prone to hyperkalaemia, which may cause cardiac death. The hyperkalaemia may be the presenting feature of the renal impairment and may commence in the first 2-3 days of life. High risk infants should have potassium levels checked 8 hourly until stable. - the baby should be in a level III hospital by this stage.

58. SEIZURES A. B. C. D. E. F. G.

Summary Introduction Differential Diagnosis Investigations Management Areas of Uncertainty in Clinical Practice References

A. Summary: -

neonatal seizures are relatively common and rarely idiopathic there are four different types of clinical seizures seizures must be differentiated from jitteriness and benign neonatal sleep myoclonus treat with anticonvulsants if the seizure is prolonged (longer than 3 minutes), frequent or associated with cardiorespiratory disturbance 70% of seizures will abate with phenobarbitone only

B. Introduction: Neonatal seizures are paroxysmal alterations in neurological function. This definition allows the inclusion of clinical seizures associated with EEG abnormalities as well as paroxysmal clinical activities (lip smacking, cycling etc.) that are not associated with EEG alterations. Newborn babies have a central nervous system that is vulnerable to epileptogenic activity, and as a result they have a relatively high incidence of seizures (1 – 2 per 1000 term infants). Seizures represent the brain’s response to a wide variety of pathological insults. As such, they are often a manifestation of significant neurological disease, they are rarely idiopathic and they are a major predictor of adverse outcome in the newborn. The most common identifiable causes are:

-

hypoxic-ischaemic encephalopathy (49%) cerebral infarction (12%) cerebral trauma (7%) infections (5%) metabolic abnormalities including hypoglycaemia (3%) narcotic drug withdrawal (4%).

C. Differential Diagnosis: During the neonatal period any unusual repetitive or stereotypic movement may represent a seizure. Alterations in autonomic functions such as blood pressure or heart rate may represent seizure activity. The relationship between a clinical seizure and abnormal electrical activity on an EEG is inconsistent. A clinical classification of neonatal seizures is outlined in the following table:

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Type

Clinical manifestation

Comments

Subtle

Eye signs: staring, deviation, blinking etc Buccal-oral-lingual: chewing, sucking, lip smacking Limbs: cycling, swimming rowing Systemic: apnoea, blood pressure alterations

It may be difficult to differentiate subtle seizures from extremes of normal behavior. Many subtle seizures are thought to arise from the basal ganglia as a result of diminished cortical inhibition. Further depression of the cortex with anticonvulsants may not alter these seizures

Clonic

Usually involve one limb or one side of the body jerking rhythmically at 1 –4 times per second.

May be a clue to an underlying focal neuropathology e.g. hemorrhage or cerebral infarction

Myoclonic

Rapid isolated jerking of muscles

Seen in drug withdrawal (especially opiates). If it occurs during sleep then it is probably "benign neonatal sleep myoclonus". Can also occur in a very severe form of encephalopathy.

Tonic

Sustained posturing of the limbs or trunk or deviation of the head. It may mimic decerebrate or decorticate posturing. Only 30% have EEG correlates.

Often difficult to treat with anticonvulsants

It is important to distinguish seizures from jitteriness and benign neonatal sleep myoclonus. The following clinical features will help separate jitteriness and benign neonatal sleep myoclonus from seizures:

Movement

Description

Jitteriness

Symmetrical rapid movements of the hands and feet Stimulus sensitive, and may be initiated by sudden movement or noise. No associated eye movements

Benign neonatal sleep myoclonus

Bilateral or unilateral jerking during sleep Occurs during active sleep Not stimulus sensitive Often involve upper > lower trunk

D. Investigations: A clear history is essential in guiding the choice of investigations. The maternal history e.g. insulin dependent diabetes mellitus and the perinatal history e.g. evidence of fetal distress in labour will provide vital clues to the aetiology of the seizures. Blood glucose, serum electrolytes, calcium and magnesium, full blood examination and packed cell volume should be obtained in all cases even when intrapartum hypoxia appears to fully explain the seizures. Neuroimaging studies are indicated where focal pathology is suspected. Seizures following traumatic delivery particularly if there is significant head trauma or if the seizures are clonic require further investigation with CT or MRI examinations. If there is any suggestion of infection, then meningitis should be suspected and CSF examination performed. If it is not possible to obtain a sample of CSF then treatment with ampicillin (100 mg/kg 12 hourly) and cefotaxime (50 mg/kg 12 hourly) should be commenced. These drug doses apply to term babies only. If the seizures are difficult to control, and/or require the use of multiple anticonvulsants then an EEG may assist determining the cause of the seizures as well as guiding treatment.

141

E. Management: The first step in treatment is to identify and treat the underlying cause e.g. hypoglycaemia. Seizure control will be very difficult unless the underlying cause is addressed. There is some controversy over when to commence anticonvulsants however an anticonvulsant should be commenced if the seizure is prolonged (longer than 3 minutes), frequent or associated with cardiorespiratory disturbance. If a decision is made to initiate treatment, the following medications are generally effective.

% infants controlled

Anticonvulsant

Loading dose

Maintenance

Phenobarbitone

20 mg/kg IV or IM over 30 minutes *

2.5 to 5 mg/kg 12 hourly, 24 hours after the loading dose

70%

15 to 20 mg/kg IVI over at least 30 minutes

4 to 5 mg/kg/dose 12 hourly in term infants starting 12 hours after the loading dose

85%

Phenytoin

Clonazepam

0.1 to 0.25 mg IV (not per kg)

0.01 mg/kg/dose 8 hourly, 8 hours after the loading dose

90-100%

Paraldehyde

0.3 ml/kg/dose PR. Rectal dosing is preferred. 0.2 ml/kg IV or IM if the rectal route is not feasible.

0.3 ml/kg/dose PR 4 to 8 hourly. 0.1 ml/kg/dose IM or IV 4 to 6 hourly

Pyridoxine **

100 mg IV or IM

50 mg daily

* Some recommend additional loading doses of 5-10 mg/kg up to a total of 50 mg/kg. However such high doses cause CNS depression, which may complicate the assessment of infants with hypoxic ischaemic encephalopathy. They may also cause respiratory depression, which may necessitate endotracheal intubation. ** Pyridoxine may be tried if the aetiology is obscure and the seizures are not responding to the usual medications.

F. Areas of Uncertainty in Clinical Practice: Routine anticonvulsant therapy following perinatal asphyxia should be restricted to those babies who are having prolonged or frequent clinical seizures. It remains unclear whether the goal of anticonvulsant therapy should be the complete elimination of abnormal EEG activity or the abolition of clinical seizures. The elimination of abnormal EEG activity may require very large doses of anticonvulsants. These may have adverse effects upon the developing brain. Similarly, it is not clear how long therapy should be continued following the initial seizures. There is no indication that prolonged treatment of anticonvulsant therapy reduces the risk for the later development of epilepsy. The only recommendation for continuing anticonvulsant therapy (phenobarbitone 3-4 mg/kg/day) is in the setting of profound neonatal encephalopathy or severe brain injury and then only for 6-8 weeks.

G. References: • • • •

Evans D, Levene M. Cochrane Database Syst Rev 2000;(2):CD001240 Hill A. Neonatal Seizures. Pediatr. Rev. 2000 21: 117-121. Rennie J. 1999 Seizures in the newborn. In, Rennie JM and Roberton NRC (eds) Textbook of Neonatology, 3rd edn. Edinburgh, Churchill Livingstone, pp 1213-1223 Menkes JH. 1991 Paroxysmal disorders. In Taeusch HW, Ballard RA and Avery ME (eds) Schaeffer and Avery's Diseases of the newborn, 6th edn, Philadelphia, W.B. Saunders Company, pp 445-449.

Other Reading/Web links: •

Volpe JJ. 2001 Neonatal seizures. In Volpe JJ, ed. Neurology of the newborn. 4th edn. Philadelphia, W.B. Saunders Company

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59. SEPSIS A. B. C. D. E. F. G. H.

Summary Introduction Risk Factors for Sepsis Recognition of systemic sepsis Investigations Management Special Circumstances Areas of Uncertainty in Clinical Practice

A. Summary: -

any baby who is unwell must be considered at risk of sepsis and appropriate antibiotics commenced as soon as possible after taking cultures inability to obtain cultures should not delay administration of antibiotics

B. Introduction: Neonatal sepsis occurs in 1 to 8 per 1000 live births with the highest incidence occurring among infants of very low birth weight and gestation. It is mandatory to have a high index of suspicion for the possibility of sepsis, as well as a low threshold for commencing antibiotic treatment. While more babies are treated than are infected the consequences of untreated sepsis are devastating. Early onset sepsis (within the first 48 hours of life):

-

often manifests with pneumonia and/or septicaemia equal male and female incidence characterised by high risk of mortality (10 to 30%) predominantly due to organisms acquired from the birth canal occasionally intrapartum haematogenous spread occurs eg Listeria over 80% of cases are due to GBS and gram negative bacteria

Late onset sepsis (after the first 48 hours):

-

due to organisms acquired either around the time of birth or in hospital eg Coagulase Negative Staphylococcus during hospitalisation in the NICU male predominance infants < 1000gms are particularly at risk mortality rate approximately 5% > 70% due to Coagulase Negative Staphylococcus and Staphylococcus Aureus, 10 - 15% due to Gram negatives. Candida is an important pathogen, particularly among extremely low birth weight infants gram negatives and GBS predominate among infections acquired outside the NICU setting

C. Risk Factors for Sepsis: Early onset sepsis:

-

prolonged ruptured membranes (> 18 hours) fetal distress maternal pyrexia (> 38° C) or overt infection eg UTI, gastroenteritis/diarrhoeal illness multiple obstetric procedures, including cervical sutures preterm delivery history of GBS infection in previous infant, GBS bacteriuria in this pregnancy

Late onset sepsis:

-

prolonged hospitalisation eg preterm infants in a NICU presence of foreign bodies eg intravenous catheters, endotracheal tubes, etc cross infection by staff and parents malformations such as urinary tract anomalies (eg vesico-ureteric reflux) or neural tube defects

143

D. Recognition of systemic sepsis: Signs are usually non-specific since other conditions cause similar clinical states (eg cardiac or respiratory failure, metabolic disorders)

-

-

-

-

-

-

General features: • pallor, lethargy, jaundice • fever, hypothermia, temperature instability (note 1/3 of confirmed sepsis cases are normothermic) • poor handling • hypoglycaemia/hyperglycaemia • blood gas derangements (including acidosis and lactate accumulation) Respiratory: • increased respiratory rate • apnoea • grunting • cyanosis CVS: • tachycardia • bradycardic episodes • poor perfusion • hypotension Cutaneous: • petechiae • bruising • bleeding from puncture sites GIT: • poor feeding • vomiting • abdominal distension • feed intolerance • bilious aspirates/vomits • loose stools CNS: • lethargy • irritability • seizures

Any baby who is unwell must be considered at risk of sepsis and appropriate antibiotics commenced as soon as possible after taking cultures. Inability to obtain cultures should not delay administration of antibiotics.

E. Investigations: General investigations include parameters important in assessment of general well being of the infant eg blood gases, true blood glucose Infection related tests:

-

-

-

Non-specific markers eg C-reactive protein (CRP), Full Blood Examination CRP rises approximately 12 hours after onset of sepsis and returns to normal within 2 to 7 days of successful treatment. If the CRP remains elevated or rises after initial improvement, care must be taken to look for possible collections, including endocarditis (particularly if 'long-lines' have been used) or fungal infection. CRP is raised in 85 % of episodes of confirmed sepsis with a specificity of 90%. It can, therefore, be normal in cases of true sepsis and should be used in conjunction with clinical signs and culture results. FBE -The Polymorphonucleocyte (PMN) count can be normal in 1/3 of cases of confirmed sepsis, but can also be elevated in the absence of infection. Neutropenia in the face of confirmed sepsis can indicate that the baby is extremely unwell. A raised immature to total white cell ratio (I:T ratio > 0.3) is about 85 % sensitive and specific - particularly for early onset sepsis. Tests to identify the infective organism

144

Early onset sepsis:

-

-

Blood culture (mandatory) Lumbar puncture (LP) should be performed where the 'index of suspicion' of meningitis is high ie abnormal conscious state or seizures. LP may need to be delayed until after the infant's condition has stabilised sufficiently to tolerate the procedure and abnormalities of coagulation status have been controlled. If the initial blood culture is positive. LP must be performed to exclude meningitis since the presence of meningitis alters the length of antibiotic treatment as well as prognosis. there is little to be gained from performing urine aspiration for culture, as haematogenous spread is the mechanism behind positive urine cultures in the first few days of life

Late onset sepsis:

-

Blood cultures (mandatory) SPA specimen of urine should be obtained, as a primary UTI is not uncommon as a cause of sepsis after 5 days of age The role of LP in late onset sepsis is controversial and depends on the clinical setting

Infants in NICU - The role of LP is limited since the commonest organism causing sepsis is the Coagulase Negative Staph (CONS). CONS rarely cause CNS infection unless a VP shunt is present. LP when CONS is isolated from blood culture is reserved for infants who are not following the expected clinical course despite appropriate antibiotics. LP is performed when the infant's condition is suggestive of meningitis or blood culture identifies an organism other than CONS. If there is a high clinical index of CNS infection, appropriate treatment should be instituted early even if the LP is delayed until the baby is stable enough to tolerate the procedure. Infants outside hospital suspected of being septic - LP should be performed to exclude CNS infection.

-

ETT cultures and skin swabs are of limited value for babies in NICU situations. Their value is as a guide to the profile and sensitivity of organisms in the nursery, particularly Staphylococcus Aureus.

F. Management: General Measures: In addition to the administration of antibiotics, great attention to supportive care is needed. Antibiotics should be considered as only part of the management of a septic neonate. - General: • thermal care • incubator nursing • phototherapy if warranted • monitoring of oxygen saturation, heart rate and blood pressure - Respiratory - support for apnoea, hypoxia, hypercapnoea, and respiratory distress - Cardiovascular: • plasma volume expanders (normal saline - 10 to 20 mls/kg initially) • inotropic support is often needed (see management of shock) - Correction of fluid, electrolyte, glucose and haematological derangements (including blood, platelets and clotting factors) - the unstable infant usually needs enteral feedings withheld. Antibiotic choice: Given the usual causative organisms the following regimes are recommended initially. Antibiotic choice can then be rationalised on the basis of culture results and clinical course. Early onset sepsis: - Benzylpenicillin - 60mg/kg IV 12 hrly 120mg/kg/dose 12 hrly if meningitis suspected - Gentamicin - 2.5 mg/kg IV 18 hrly if >32 weeks, 24hrly if 28-32 weeks, 36 hrly if <28 weeks. Note: both can be given IM if IV access is not possible If history or clinical appearance suggests the possibility of Listeria, amoxycillin 50mg/kg IV 12hourly can be used instead of benzylpenicillin (although data indicating that this is superior is lacking). For treatment of meningitis (until sensitivities are known): - Cefotaxime - 50mg/kg/dose 12 hourly for preterm babies or term babies in the first week of life, 8 hourly after that time - Amoxycillin - 50mg/kg/dose 12 hourly for preterm babies or term babies in the first week of life, 8 hourly after that time

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Late onset sepsis: Vancomycin and gentamicin are the usual first line combination for patients in a NICU unit. For other infants, flucloxacillin and gentamicin are the usual first choice antibiotics. Vancomycin 15 mg/kg 18 hrly for term babies. Gentamicin

2.5 mg/kg 18hrly for term babies.

Flucloxacillin 25mg/kg/dose 12 hourly for preterm babies or term babies in the first week of life, 6-8 hourly after that time. Doses of antibiotics need to be adjusted for age of the baby and on the basis of levels in the case of gentamicin and vancomcycin. An aminoglycoside other than gentamicin may be used in some hospitals at times depending on the profile of prevalent organisms. When to stop Antibiotics: Duration of antibiotic treatment depends upon the clinical condition of the infant and the organism identified on culture. - where the likelihood of infection is low, with a baby in good condition and infective indices negative, antibiotics can be ceased if cultures are negative after 48 hours - sepsis strongly suspected, despite negative blood culture at 48 hours. It is advisable to continue antibiotics for at least 5 days providing infective indices have normalised. Another approach is to continue antibiotics for 48 hours after indices have normalised - proven gram negative bacteraemia, with clear CSF, treat for 10 to 14 days, antibiotics can be rationalised in the face of culture and sensitivities - proven GBS bacteraemia, with clear CSF, 10 days treatment should be sufficient - meningitis, treat for 14 days for GBS and 21 days for gram negative organisms. In some centres, 48hourly LPs are performed in cases of gram negative meningitis, with treatment continuing for 14 days after the first negative culture - in practice this usually equates with a 21 day treatment course - UTI - treat with IV antibiotics for at least 5 days, a total of 10 days treatment is needed. The infant can be managed with appropriate oral antibiotics for the latter half of the treatment course if clinical condition is satisfactory. Ongoing prophylactic antibiotics will be needed until renal investigations are completed

G. Special Circumstances: - The GBS colonised mother: At delivery approximately 15% of women are colonised with GBS. Up to 70% of infants born to colonised women are themselves colonised. Infection occurs in 1% of colonised infants. 75% of early onset GBS disease in neonates occurs in term babies. The incidence of GBS disease varies, with the rate being 3 per 1000 live births in the USA, compared to 0.3 per 1000 in Australia and the UK. The risk is 3 times higher in the Aboriginal community. Screening for GBS remains the subject of heated debate, but it is known that intrapartum administration of antibiotics (penicillin or amoxycillin) reduces neonatal colonisation by 90%, and early onset GBS disease by 90%. The CDC in the USA recommends that all women be screened with anorectal and vaginal swabs at 35 -37 weeks' gestation. Intrapartum antibiotics are given according to the following strategies: - if screening is performed administer to: • GBS colonised women • Non-colonised women with risk factors present - if screening is not performed administer to women with risk factors: • Preterm onset of labour (<37weeks) • ROM for >18 hours • Maternal fever (>38°C) • Previous baby with invasive GBS disease • GBS bacteriuria this pregnancy Use of the CDC guidelines is estimated to result in around 27% of women receiving antibiotics, with an associated reduction in early onset GBS disease of around 85%. The disadvantages of such an approach are the risk of maternal complications (anaphylaxis), and the cost (GBS rates of >0.5 per 1000 live births are needed to justify such an approach on a cost-effectiveness basis). Intrapartum chemoprophylaxis consists of penicillin 1.2gms IV statim, then 0.6gms 4hrly (erythromycin can be used in cases of penicillin allergy). Should the infant be delivered before prophylaxis has been administered to the mother, or within 4 hours of the initial dose, the infant should be observed closely in hospital for 48 hours. Some workers recommend giving a single intramuscular injection of 100mg penicillin, IM, to such an infant while others

146

recommend taking an FBE and blood culture prior to observation. Occasional treatment failure has been associated with the single IM dose regime. If the infant is initially (or becomes) symptomatic, or if significant prematurity (<35 weeks gestation) is present, the infant should undergo a septic evaluation and treatment with intravenous antibiotics despite maternal intrapartum prophylaxis.

-

Prolonged Rupture of Membranes (PROM):

The majority of women will come into labour within 24 hours of rupture of the membranes; however, this may be delayed in up to 4% of cases. PROM for greater than 18 hours may lead to increased risk of infection in mother and baby - particularly if the mother is GBS positive or undergoes repeated vaginal examinations. In practice, the risk is greatest for preterm infants, but 75% of early onset GBS sepsis occurs in term babies. Since there is a lack of evidence from trials available there is debate as to the role of prophylactic antibiotics in PROM. Obstetric staff will need to consider signs of possible maternal sepsis, as well as risk factors such as GBS colonisation in deciding to administer antenatal antibiotics. Babies born with a background of PROM need to be viewed as potentially at risk of sepsis. Preterm infants, particularly those <35 weeks, are usually screened for sepsis and treated with IV antibiotics until infection in the baby has been excluded. Term infants: • if there are no risk factors, apart from the PROM, the infant is usually observed closely and treated only if symptoms develop • if there is a risk factor present in addition to PROM, such as GBS positive mother, maternal intrapartum fever or suspected chorioamnionitis that infant should be treated as potentially septic, even if completely asymptomatic • any symptomatic baby needs septic evaluation performed and treatment for infection regardless of the presence or absence of risk factors

-

Fungal sepsis:

Generally seen in VLBW infants in NICU. Risk factors include multiple courses of IV antibiotics, presence of central lines and extensive areas of skin breakdown. Consideration of fungal sepsis is particularly necessary when such infants deteriorate whilst receiving antibiotics. Empirical treatment with Amphotericin until cultures are reported as clear for fungal organisms is appropriate. SPA of urine must be performed prior to starting Amphotericin as bag specimens will often be contaminated with Candida colonising the skin. If fungal sepsis is confirmed, then the addition of a further antifungal (e.g. fluconazole mg/kg stat, then 2mg/kg 48hrly) may be useful. Duration of treatment depends upon the site of infection but generally ranges from 3 to 6 weeks. Ultrasound of the kidneys and formal fundoscopy should be performed.

H. Areas of Uncertainty in Clinical Practice: -

The role of antigen tests for GBS is controversial:

Urine specimens for GBS antigen can be positive when babies are colonised, even when a SPA specimen is taken. If a bag specimen is used, then contamination with skin GBS colonisation will result in a positive test. Antigen tests are more sensitive and specific for CSF specimens, but cannot be relied upon to exclude infection. Antigen testing results need to be viewed from the point of view of adding supplementary evidence of possible infection, but cannot be relied upon to prove or disprove GBS infection, and are thus of limited value. Similar limitations exist in testing for other bacterial antigens.

-

Antifungal prophylaxis:

A recent Cochrane review failed to demonstrate a reduction in fungal colonisation among patients receiving prophylactic oral nystatin compared to placebo. All patients in these trials were immuno-compromised but beyond the neonatal period. A RCT of intravenous fluconazole compared to placebo during the first 6 weeks of life in 100 infants of less than 1000gm birthweight showed a reduction in fungal colonization and invasive fungal infection.

-

Treatment with Granulocyte Colony Stimulating Factor (G-CSF):

G-CSF has been shown to increase PMN counts in VLBW babies, but the effect on sepsis reduction or mortality from sepsis has not been demonstrated.

-

Intravenous immunoglobulin (IVIG):

Studies involving IVIG show a possible improvement in mortality in babies given IVIG as part of the treatment of sepsis. However, larger trials are needed to examine the role of IVIG in neonates with sepsis.

-

Other ancillary treatments that have been used include exchange transfusion and neutrophil transfusions, but insufficient data is available to recommend their use.

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Further Reading: • • • • •

Isaacs D, Moxon ER. Handbook of Neonatal Infections - a practical guide. WB Saunders, London. 1999. Remington JS, Klein JO. Infectious Diseases of the Fetus and Newborn Infant 5Th Ed. WB Saunders, Philadelphia. 2000. CDC (Center for Diseases Control). Prevention of perinatal group B streptococcal diseases: a public health perspective. MMWR 1996: 45(RR-7). Smaill, F. Intrapartum antibiotics for Group B streptococcal colonisation. Cochrane Pregnancy and Childbirth Group. The Cochrane Library. Flenady, V. King, J. Antibiotics for prelabour rupture of membranes at or near term. [Protocol] Cochrane Pregnancy and Childbirth Group. The Cochrane Library.

60. SINGLE UMBILICAL ARTERY A. B. C. D. E.

Introduction Obstetric Complications Paediatric Complications Management References

A. Introduction: The first postpartum screening programs for single umbilical artery (SUA) were established in 1955 in obstetric centres following the discovery of an association with other congenital abnormalities. The pathogenesis of a single umbilical artery (SUA) is thought to be secondary to vessel atrophy of a previously normal cord in the mid trimester. On occasion a rudimentary second artery is seen histologically (although, the prognostic implications of this are unclear). Antenatal diagnosis may be impeded by fetal position Diagnosis after birth is by either gross or histological examination of the cord (concordance between the two is good). Prevalence is equal in males and females. The overall quoted incidence for isolated SUA is 0.26% to 0.32% of live births. This increases to 0.63 – 1.0% if SUA associated with malformations or fetal loss is included. A single umbilical artery is 3 to 4 times more common in twins.

B. Obstetric Complications: 50% of fetuses with SUA have associated chromosomal or congenital malformations (typically cardiac, neurological, renal). Virtually any abnormality has been associated with SUA rather than any specific syndromes. SUA is associated with an increased perinatal mortality rate of 22% because of the association with congenital malformations. Isolated SUA is associated with IUGR (10% versus 4.4% with a three-vessel cord).

C. Paediatric Complications: An isolated SUA is associated with renal malformations in 7-9% of infants. Vesicoureteric reflux (VUR) is the most common abnormality occurring in 4% of infants with an isolated SUA. In a meta analysis of 26 studies the incidence of any renal abnormality associated with isolated SUA was 8 %, with only 4% requiring treatment of the abnormality. From this meta analysis the investigation of 14 cases of isolated SUA would yield one patient requiring treatment. In another study VUR was also the most common abnormality requiring treatment and 3 out of 5 of their patients had a urinary tract infection (UTI) before the age of three months.

D. Management: Prenatal management of a double vessel cord includes:

-

thorough antenatal scan and fetal echocardiogram consideration for chromosome analysis (particularly if another soft marker for aneuploidy is noted).

Isolated SUA should have close clinical follow up to assess intrauterine growth with repeat ultrasound scans as indicated clinically. Postnatal examination aims to exclude congenital abnormalities especially cardiac, neurologic and renal. Infants born with SUA without associated abnormalities should have a routine postnatal examination. Follow up should include a renal ultrasound and micturating cystourethrogram to exclude vesico-ureteric reflux should be considered (as a small proportion of infants with VUR will have a normal renal ultrasound).

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E. References: • • • •

Benirschke, K and Brown, W H. A vascular anomaly of the umbilical cord: the absence of one artery in the umbilical cord of normal and abnormal fetuses. Obstetrics and Gynecology 6, 399-404. 1955. Catanzarite, V A, Hendricks, S K, Maida, C, Westbrook, C, Cousins, L, and Schrimmer, D. Prenatal diagnosis of the two vessel cord implications for patient counselling and obstetric management. Ultrasound in Obstetrics and Gynecology 5, 98-105. 1995. Bourke, W G, Clarke, T A, Matthews, T G, O'Halpin, D, and Donoghue, V B. Isolated single umbilical artery- the case for routine renal scanning. Archives of Diseases of Childhood 68, 600-601. 1993. Thummala, M R, Raju, T N, and Langenberg, P. Isolated single umbilical artery anomaly and the risk for congenital malformations : a meta analysis. Journal of Pediatric Surgery 33(4), 580-585. 1998.

61. SMALL FOR GESTATIONAL AGE INFANTS A. B. C. D. E. F. G. H. I.

Definition Types Aetiology Physical Examination Problems in SGA Investigations Management Outcome References

A. Definition: Small for gestational age infants are defined as having a birth weight more than 2SD below the mean or less than the 10th percentile of a population specific weight versus gestational age plot.

B. Types: Symmetric: Weight, head circumference and length all below the 10th percentile. Brain growth may be limited.

Causes

-

intrinsic fetal causes intrauterine infection severe placental insufficiency constitutionally small infant

Asymmetric: Weight below the 10th percentile but head circumference and length relatively preserved. Brain growth relatively spared.

Causes

- interference with placental function or maternal health in 3rd trimester.

Infants whose weight is greater than the 10th percentile but who are thin relative to their length and head circumference are at similar risk of neonatal complications as SGA infants. They should be considered "relatively" SGA (Clifford syndrome). The weight/length ratio (or the Ponderal Index = [weight (g)]/[length (cm)]3 ) is less than normal for such infants. However, unless great care is taken with the measurement of length the calculated index can be misleading.

C. Aetiology: Fetal

- chromosome disorders (eg Trisomy 21, Trisomy 18) - chronic fetal infection (eg CMV, Rubella, Syphilis, Toxoplasmosis) - congenital malformations: including congenital heart disease, diaphragmatic hernia, tracheo-oesophageal fistula

- syndrome complex - radiation - multiple gestation relates more to placental limitation rather than intrinsic baby problem

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Mother

-

pregnancy induced hypertension hypertension or renal disease or both hypoxaemia (high altitude, cyanotic cardiac or pulmonary disease) malnutrition or chronic illness drugs (narcotics, alcohol, cigarettes, cocaine, antimetabolites)

Placental

-

decreased placental weight or cellularity or both decrease in surface area, infarction villous placentitis (bacterial, viral, parasitic) tumour (chorioangioma, hydatiform mole) placental separation twin to twin transfusion syndrome

Constitutional - familial and racial background

D. Physical Examination: Physical examination of the SGA infant must include a detailed search for associated abnormalities. - dysmorphic features "unusual" facies: • abnormal hands and feet • abnormal palmar creases • in addition to gross anomalies - ocular disorders, such as: • cataracts • cloudy cornea • chorioretinitis - features of intrauterine infection: • hepatosplenomegaly • jaundice • blueberry-muffin rash

E. Problems in SGA: Problem

Pathogenesis

Intrauterine fetal demise

Hypoxia, acidosis, infection and lethal anomaly

Perinatal asphyxia

Decreased uteroplacental perfusion in labour chronic fetal hypoxia-acidosis

Hypoglycemia

Decreased tissue glycogen stores, decreased gluconeogenesis and high glucose requirements

Polycythemia -hyperviscosity

fetal hypoxia with increased erythropoietin production

Hypothermia

Large surface area, poor subcutaneous fat stores

Respiratory distress

intrauterine pneumonia, meconium aspiration syndrome, PPHN

F. Investigations: Investigations are required to: - screen for hypoglycemia - assess the infant according to clinical signs: • polycythemia and hypocalcaemia are more common. • if respiratory distress present, ABG and Chest X-ray. - establish the cause of growth restriction: • intrauterine infection suspected; check maternal TORCH serology and screen infant urine and saliva for CMV (further investigation will be required if suspicion confirmed). • if dysmorphic; genetic consultation and chromosome studies • if showing signs of withdrawal urine for drug screen. • ultrasonography and echocardiography, if clinically indicated

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G. Management: At Delivery: Place promptly under a radiant warmer and dry. Infants with severe SGA, particularly in association with fetal distress, are at risk of aspiration of meconium , hypoxaemia, hypotension, mixed metabolic and respiratory acidosis and persistent pulmonary hypertension. Hypothermia: Nurse in a thermoneutral environment Hypoglycemia: Monitor blood glucose and commence early enteral feeds or intravenous glucose infusion. Necrotisingenterocolitis: Infants, particularly preterm SGA, found to have placental insufficiency and abnormal umbilical artery Doppler studies may be at particular risk of developing NEC or gastrointestinal perforation. Enteral feeding should be increased gradually. Polycythemia: Partial volume exchange may be required for symptomatic infants.

H. Outcome: Principally determined by the cause. Postnatal physical growth: Symmetric SGA - smaller and relatively under weight throughout life. Asymmetric SGA - accelerated velocity of growth ("catch up growth") in first 6 months and normal development. Neurodevelopmental outcome: Term SGA - no increase risk of severe neurologic morbidity compared to term AGA infants. However increased hyperactivity, short attention span and learning problems Preterm SGA - Minor neurologic abnormalities more common than in preterm AGA infants.

I. References: • • •

Avery GB, Fletcher MA, MacDonald MG, eds. Neonatology. 5th ed. Philadelphia, Pa: Lippincott Williams & Wilkins, 1999:411-444. Rennie JM, Roberton NRC (Eds). Textbook of Neonatology, 3rd edition. Churchill Livingstone , Edinburgh, 1999. Patti J Thureen, Marianne S Anderson and William W. Hay, Jr. Small for gestational age, NeoReviews; 2001; E139-e149.

Web Links: •

www.neoreviews.aapjournals.org

62. SUPRAVENTRICULAR TACHYCARDIA A. B. C. D. E. F.

Summary Introduction Differential Diagnosis Investigation Initial management of re-entry atrio-ventricular tachycardia Further Reading

A. Summary: -

support in diagnosis and management of patients can be obtained by contacting the on-call Paediatric Cardiologist at either the Royal Children's Hospital (03 9345 5522) or Monash Medical Centre (03 9594 6666) vagal stimulation or adenosine is effective in reverting most atrio-ventricular SVTs utilising an accessory pathway pharmacological management is usually appropriate for the first year of life after SVT in the neonatal period intravenous Verapamil should never be given to infants because of the risk of refractory hypotension

B. Introduction: Supraventricular tachycardias (SVTs) are defined as those requiring tissue above the bifurcation of the bundle of His for their continuance. SVTs may be either atrial or atrio-ventricular and these groups may be further subclassified by mechanism into automatic or re-entry. Most SVTs in the neonate are re-entry atrio-ventricular

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SVTs utilising an accessory pathway. Most commonly the circuit of the tachycardia travels down the AV node and retrogradely up the accessory pathway. If during sinus rhythm the pathway can also conduct anterogradely (downwards) then pre-excitation can be seen on the 12 lead ECG. SVT may initially be asymptomatic, but when prolonged may result in congestive cardiac failure and shock after a variable period. Sustained/paroxysmal SVT may develop in-utero and may result in hydrops. Cardiology consultation regarding diagnostic and therapeutic management issues is available at any time through the switchboard of either Monash Medical Centre (Phone 03 9594 6666) or The Royal Childrens Hospital (Phone 03 9345 5522).

C. Differential Diagnosis: -

sinus tachycardia at rates of up to 230 beats per minute can occur in the neonate, especially in association with fever, anaemia, sepsis and pain ventricular tachycardia in the neonate may have a relatively narrow QRS complex and must always be considered SVTs other than atrio-ventricular SVTs utilising an accessory pathway are always a possibility

D. Investigation: -

initially this includes physical examination, ECG and echocardiography physical examination including general appearance, pulse, BP, murmur, heart failure a 12 lead ECG helps define the mechanism of the tachycardia. Later a 12 lead ECG in sinus rhythm may show pre-excitation or evidence of structural heart disease a Holter monitor may show evidence of intermittent pre-excitation and initiating triggers such as premature atrial contractions. If pre-excitation is absent on the 12 lead ECG it may be appropriate to obtain this as an outpatient via a cardiologist an echocardiogram should be obtained after stabilisation. There are 5 important structural associations of atrioventricular re-entry SVT; all may be silent to clinical examination. These include • Ebstein’s malformation: • congenitally corrected transposition • dilated and hypertrophic cardiomyopathy • myocardial tumours

E. Initial management of re-entry atrio-ventricular tachycardia: -

-

full good quality 12 lead ECG - confirm that the tachycardia is narrow complex assess patient: • if patient relatively stable: Perform vagal manoeuvres ƒ icepack for infants (either commercially available or place crushed ice inside 2 plastic bags) - apply icepack to face; be careful of eyes and do not hold on face too long as ice can "burn" an infant’s skin ƒ oropharyngeal suctioning or gag with spatula ƒ do not put pressure on eyeballs as this can result in retinal detachment ƒ do not use carotid sinus massage as this may compromise cerebral circulation • if the patient is unstable: Appropriate resuscitative measures should be instituted including ƒ intubation and assisted ventilation (good treatment for CCF) ƒ consideration of D/C version ƒ review of blood gases, glucose, electrolytes (sodium, potassium, ionised calcium, magnesium) and lactate intravenous adenosine if no contra-indications (contra-indicated in adenosine-deaminase deficiency which is a rare form of immune deficiency) • need full resuscitation facilities available • babies should have continuous ECG monitoring throughout administration of adenosine • adenosine can be given in a starting dose of 0.05mg/kg, with doses increasing by 0.05 mg/kg up to 0.25mg/kg. Need to wait 2 minutes between doses and check patient’s vital signs. May use 0.30mg/kg for recalcitrant cases with Cardiologist approval • adenosine should be given very quickly and as proximally in the intravenous set-up as possible. A three-way tap should be used so that the adenosine can be quickly flushed with normal saline. When the volume of adenosine is small it should be diluted with normal saline so that the drug has the chance to reach the body. • If 0.25mg/kg fails this can be repeated once if the patient is stable.

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• • • • •

The recorded strip immediately after conversion to sinus rhythm has occurred should be saved and inspected for concealed pre-excitation which may be revealed during the first few beats after conversion to sinus rhythm. After a patient has been reverted a 12 lead ECG should be performed to look for Pre-excitation and other abnormality. Rapid re-initiation of tachycardia is not uncommon, mostly due to premature atrial contractions stimulated by the adenosine. If this occurs it is reasonable to try adenosine again. On occasions adenosine may cause a major pause or initiate atrial fibrillation. If the diagnosis is an atrial tachycardia this may be revealed by adenosine which causes transient atrio-ventricular block and multiple P-waves will be seen in a row. Some atrial ectopic tachycardias are sensitive to adenosine so that the atrial impulse will stop.

-

Direct Current Cardioversion or defibrillation should be considered for unstable patients after intubation and initiation of ventilation. • This is best undertaken after consultation with a cardiologist unless the urgency is extreme. • Infants require intravenous access and suitable sedation and analgesia. • For tachycardias with a regular well-defined QRS complex the discharge should be synchronised with the QRS complex to avoid ventricular fibrillation. • For ventricular fibrillation or polymorphic VT an unsynchronised shock is necessary, otherwise the device will continuously delay the shock whilst trying to track the QRS complex. • Connect the defibrillator ECG leads to the patient to obtain an ECG recording. Confirm QRS synchronisation (not T wave) by the on screen signal. • Select appropriate sized paddles, ensuring there is complete coverage of the paddle by gel or gel pads. Avoid gel on the skin as this may form a conductive bridge between the paddles. • Preferred Position; sternum paddle at the base of the heart, apex addle at the apex/axilla. If there is insufficient area the sternum paddle may be applied to the front of the chest, while the apex paddle may be placed over the back, giving a front to back shock. • SVTs usually require 1 joule per kg and ventricular arrhythmia 2 - 4 joules per kg.

-

Intravenous Verapamil should NEVER be given to infants.

-

The follow up plan, including the prescription of maintenance medication should be made in consultation with the RCH Cardiology Fellow/Cardiologist. • Patients with recurrent re-initiation of tachycardia need discussion with the on-call Cardiologist and may require transfer to the Royal Children’s Hospital. • Digoxin should never be given in the presence of pre-excitation. • The first line maintenance medication would likely be a beta-blocker. These should be initiated in hospital for neonates and monitoring for hypoglycaemia should be performed. • Appropriate adjustments in dose should be made for premature neonates and therapeutic drug monitoring or monitoring of ECG parameters is performed if appropriate. • The parents need to be taught how to take the pulse. It may be appropriate for this to be checked prior to putting the babe to sleep and the pulse can be checked if the babe is “off colour”.

-

Cardiology follow-up is imperative if pre-excitation is present and optimal for other patients.

-

Radio-frequency catheter ablation of arrhythmia substrate is usually reserved for children of school age and is rarely required in the neonate.

-

Accessory pathway function disappears in 40% of patients by the age of 1 year. If pathway conduction persists symptoms may settle in the first year only to return at 7 or 8 years of age (“Cardiac Puberty”).

F. Further Reading: •

Bauersfeld U. Pfammatter JP. Jaeggi E. Treatment of supraventricular tachycardias in the new millennium--drugs or radiofrequency catheter ablation? European Journal of Pediatrics. 160(1):1-9, 2001.

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63. SURFACTANT REPLACEMENT THERAPY A. B. C. D. E. F. G. H. I.

Summary Introduction Preparation Dosage Procedure Post-dosing Complications Areas of Uncertainty in Clinical Practice Further Reading

A. Summary: - early administration of surfactant to intubated infants with RDS is desirable - when considering surfactant therapy prior to NICU transfer consultation with a neonatologist at the receiving NICU or the NETS consultant will facilitate care

B. Introduction: Consider using Surfactant when: - presumed diagnosis is HMD (on clinical grounds or CXR) and - infant is intubated, regardless of gestation and requiring FiO2 > 35% Treatment is not usually commenced if these criteria are only fulfilled after the infant is 48 hours old.

C. Preparation Access to X-ray and blood gas facilities is essential when considering the use of surfactant therapy. Preparation includes: - correction of hypothermia, hypoglycaemia, acidosis , and hypovolaemia are essential aspects of treatment - antibiotics (see RDS Section) - arterial blood gas assessment is required after commencing assisted ventilation; the placement of an arterial line is desirable, but optional - placement of a saturation monitor or non-invasive transcutaneous oxygen is mandatory - a CXR must be performed to confirm diagnosis and check position of endotracheal (ET) tube prior to giving surfactant

D. Dosage: Survanta, 4mL/kg, given via a gavage tube cut so that the tip lies 1cm above the end of the endotracheal tube. Do not shake the vial. Warm the dose to room temperature before administration (this will take about 20 minutes). Note. When based on the infant's weight, a vial of Survanta may supply more than one dose, withdraw required dose and the remainder in a second syringe. This then must be capped, labelled and refrigerated with the empty vial so that this can be sent with the infant to the receiving NICU. As Survanta contains no preservatives, aseptic technique must be used.

E. Procedure: The infant is placed supine and surfactant given as quickly as tolerated so that the total dose is usually given over 3 - 5 minutes. Surfactant (especially Survanta) can occlude the ET tube and it may be necessary to cease dosage until the tube is cleared and chest wall movement resumes. Ventilator support or inspired oxygen may need to be temporarily increased. At high ventilator rates (>40) regurgitation of surfactant may occur in the expiratory circuit, this can be remedied by smaller boluses and/or by reducing the ventilator rate.

F. Post Dosing: -

-

document oxygen saturation, pO2, pCO2, ventilator settings, FiO2, and notable events every 10 minutes for 30 minutes. Then revert to normal frequency of observations avoid suctioning the endotracheal tube for 2 hours post-administration unless clear-cut signs of airway obstruction are present. If during or immediately after Surfactant administration oxygen saturation falls associated with lack of chest movement, increase the PIP until good chest movement is observed, then once condition improves try to reduce PIP to original levels marked improvements may occur within minutes of administration. Therefore, frequent and careful clinical observation and monitoring of systematic oxygenation are essential to avoid hyper-oxygenation or exposure to excessive peak inspiratory pressures repeat arterial blood gas measurement 30 minutes after dosing with surfactant

154

G. Complications: - pneumothorax - due to sudden changes in pulmonary compliance if ventilator settings are not -

appropriately changed pulmonary haemorrhage - low incidence, but reported, best not to decrease PEEP below 5cm H2O

H. Areas of Uncertainty in Clinical Practice: - Prophylactic versus Rescue therapy. Prophylactic use of surfactant for infants judged to be 'at risk' of developing respiratory distress syndrome (intubated infants less than 30-32 weeks gestation) has been demonstrated to improve clinical outcome. Infants have less pneumothoraces, less pulmonary interstitial emphysema and a lower mortality. However, criteria to judge which infants are "at risk" are not clear.

I. Further Reading: •

Prophylactic versus selective use of surfactant for preventing morbidity and mortality in preterm infants. Soll RF, Morley CJ Cochrane Database of Systematic Reviews. Issue 1, 2001

64. THROMBOCYTOPENIA A. B. C. D. E. F. G. H. I.

Summary Introduction Differential Diagnosis of thrombocytopenia in babies by age at presentation Neonatal alloimmune thrombocytopenia (NAITP) Platelet function Management of thrombocytopenia Specific treatment required for NAITP Areas of uncertainty in Clinical Practice References

A. Summary: -

the well infant who presents unexpectedly on the first day of life with extensive bruising and/or a petechial rash and who is found to have isolated thrombocytopenia (TP) (platelet count <100 x 109/L) without an obvious cause must be presumed to have neonatal alloimmune thrombocytopenia until proven otherwise although mild TP is common, most infants do not require treatment the decision to provide a platelet transfusion should depend on the presence or absence of symptoms, sepsis, DIC, surgery or invasive procedures

B. Introduction: Thrombocytopenia (TP) in the newborn is defined as a platelet count less than 150 x 109/L. This occurs in 1-4% of all newborn babies. The majority of episodes of TP present during the first 72 hours of life. The highest incidence of TP is in sick, preterm babies (40-70%). Indeed, TP is the most common haematological abnormality in the NICU. Nearly 25% of sick infants develop TP, which is trivial for some infants with a platelet count of 100-150 x 109/L. In more than 50% of affected infants platelet counts fall below 100 x 109/L and 20% of infants have platelet counts <50 x 109/L. Automated platelet counts may be abnormally low due to platelet aggregation in sample. Low results should be confirmed by blood film examination and often a repeat sample (arterial or venous). This topic focuses on the differential diagnosis and management of TP. Because the most likely cause of severe TP in a baby remaining in a level ll hospital is Neonatal Alloimmune TP (NAITP), special attention is given to this condition.

C. Differential Diagnosis of thrombocytopenia in babies by age at presentation: -

-

Fetus:

• • • • • •

neonatal alloimmune TP (NAITP) maternal autoimmune disease (Idiopathic TP, SLE) congenital infections (CMV, Toxoplasmosis, Rubella) severe rhesus disease chromosomal disorders (trisomy 21, 18, 13) rare inherited disorders (TAR - TP with Absent Radii) Neonate < 72 hours of age: • placental insufficiency (PET, IUGR, diabetes) • birth asphyxia

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• • • • • •

-

perinatal bacterial infection (GBS, E. coli. Listeria) congenital infection (CMV, Toxoplasmosis, Rubella) NAITP maternal autoimmune disease (ITP, SLE) thrombosis (renal vein, aortic) rare inherited disorders (TAR, Wiskott-Aldrich syndrome) Neonate > 72 hours of age: • bacterial infection (nosocomial) • infected indwelling lines • NEC • maternal autoimmune disorders (ITP, SLE) • congenital infection (CMV, Toxoplasmosis, Rubella) • rare inherited disorders (TAR, Wiskott-Aldrich syndrome)

D. Neonatal Alloimmune Thrombocytopenia (NAITP): -

in contrast to Rh alloimmunisation, 40-60% cases in first born 75-90 % subsequent pregnancies are affected severe cases in fetus or newborn occur in 1 in 1200 pregnancies untreated, intracranial haemorrhage occurs in 10-30% of cases overall fetal and neonatal mortality in 6-13% of cases long-term neurodevelopmental sequelae in 20-25% of survivors diagnosed by demonstration of fetomaternal incompatibility for a platelet surface antigen and presence of maternal platelet alloantibodies that react with a 'foreign' antigen present on platelets of the infant and father but not the mother's platelets all children with suspected or proven NAITP warrant a cranial ultrasound to exclude intracranial haemorrhage

E. Platelet function (but not absolute count) may be impaired with: -

maternal aspirin - not usually severe Indomethacin infant of diabetic mothers - possibility of enhanced platelet reactivity rarely inherited platelet function defect

F. Management of Thrombocytopenia: Note that the risk of bleeding is increased where there is: - decreased production rather than increased destruction - platelet function defect plus thrombocytopenia - the platelet count < 50 x 109/L There is no accepted 'safe' level of platelets in neonates. Platelet transfusions need to be considered for each individual based on the platelet count, the clinical circumstance and the presence or absence of bleeding. The underlying cause should be treated, if possible. Potential triggers for platelet transfusion include:

Platelet Count

Clinical Condition

Normal platelet count Platelet dysfunction and clinical bleeding Platelet count < 100

Major bleeding Surgery DIC and bleeding Sepsis with rapid deterioration

Platelet count < 50

Minor bleeding Exchange transfusion Preterm

Platelet count < 30

Asymptomatic term infant 156

The recommended volume of platelets to be transfused is 10 - 20ml/kg. This should transiently increase the platelet count by 50 - 100 x 109/L. Transfuse over 30 minutes and monitor platelet count 1 hour post transfusion. Ensure that the platelets are:

-

leukocyte-depleted CMV-negative (if unknown, filtering may be required before transfusion) where possible, ABO compatible plasma irradiated if infant is immunocompromised

G. Specific treatment required for NAITP: -

use washed, irradiated maternal platelets (certain compatibility, availability, safety)

-

antigen-compatible donor platelets

-

random platelets only in emergency situations high dose intravenous IgG may be effective in the absence of/in addition to maternal platelets • 1 g/kg for 2 days

OR

H. Areas of uncertainty in Clinical Practice: -

a 'safe' platelet count for newborn infants has not yet been identified evidence-based guidelines for platelet transfusion therapy are yet to be defined there is little evidence that steroids and exchange transfusion have a therapeutic role in NAITP

I. References: • • • •

Roberts IAG, Murray NA. Review. Management of thrombocytopenia in neonates. Br J Haematol 1999; 105:864-70 Blanchette VC, Johnson J, Rand M. The management of alloimmune neonatal thrombocytopenia. Bailliere's Clinical Haematology 2000;13:365-90 Letsky EA, Greaves M. Guideline. Guidelines on the investigation and management of thrombocytopenia in pregnancy and neonatal alloimmune thrombocytopenia. Br J Haematol 1996;95:21-26 Roberts AG, Murray NA. Neonatal thrombocytopenia: new insights into pathogenesis and implications for clinical management. Current Opinion in Pediatrics. 2001;13:16-21

65. THROMBOSIS IN NEWBORNS A. B. C. D. E. F. G. H.

Summary Introduction Venous Thrombosis Arterial Thrombosis Diagnosis Treatment Outcome Further Reading

A. Summary: -

thrombosis in newborns is underdiagnosed most thromboembolisms, whether of arterial or venous in origin are related in intravascular devices there is limited information available on thrombosis in newborns, hence specific treatment recommendations cannot be made decisions to "treat" or "not to treat" are both active decisions management of each baby needs to be individualised and should always include consultation with a Paediatric Haematologist

B. Introduction: Newborns comprise the largest group of children developing thromboembolic events, although the frequency is significantly less than for adults. The incidence reported in international registries has varied from 0.24 per 10,000 admissions to NICU to 0.51 per 10,000 births. Approximately half are venous and half are arterial.

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C. Venous Thrombosis: 1. Central venous line (CVL) related thrombosis: Over 80% of venous thromboembolism (VTE) in newborns are secondary to CVLs. Endothelial damage, disrupted blood flow, thrombogenic catheter material and infusion of drugs and TPN are the possible mechanisms to thrombus formation.

-

Acutely, TEs result in loss of CVL patency, swelling and discolouration of affected limb. Associated atrial thrombus may give rise to cardiac failure and appearance of a murmur. Associated pulmonary embolus may give rise to respiratory insufficiency. Long term effects are prominent collateral vessels, repeated loss of CVL patency requiring repeated replacement and post thrombotic syndrome. Portal hypertension and its sequelae are the specific long term complications of UVC related thrombus. The accuracy of non-invasive methods for the diagnosis of VTEs in newborns is unknown. Ultrasound is the most commonly used method, its sensitivity is variable depending on the area studied, being high for neck vessels and very low for veins of the abdomen and pelvis.

2. Renal vein thrombosis (RVT):

-

-

RVT is the second most common VTE in newborns and comprises 10% of all VTEs Most present in the first week of life 25% are bilateral Associated conditions include: • sepsis • shock • cyanotic congenital heart disease • asphyxia • polycythemia • maternal diabetes • dehydration Presentation is with a palpable flank mass, haematuria, thrombocytopenia, proteinuria with or without renal impairment Ultrasound is the most commonly used diagnostic test as it is non-invasive and has high sensitivity for an enlarged kidney, which is an important finding initially in RVT.

3. Sinovenous thrombosis (SVT):

-

SVT is underdiagnosed in newborns as the presentation can mimic many other non thrombotic conditions Commonly seen symptoms of SVT are seizures and lethargy. Neurological deficit can be seen, although infrequently Extensive SVT can present with tense anterior fontanelle, dilated scalp veins and separation of sutures Sepsis and dehydration increase the risk of SVT and perinatal asphyxia is commonly seen in association with SVT MRI with venography (MRV) is the most sensitive and specific test for diagnosing SVT.

4. Treatment of Venous Thrombosis: There is paucity of evidence to make specific and strong recommendations for anticoagulant treatment in newborns. The efficacy of treatment and the risk of bleeding differs in newborns from that in children and adults. The site of the thrombus, presence or possibility of loss of organ function, associated conditions that may alter the bleeding risk usually influence the use and choice of therapy. Therapeutic options include: - anticoagulation - thrombolytic therapy - no treatment Anticoagulation and thrombolytic therapy in newborns in general should only be used in tertiary level NICU after consultation with a paediatric haematologist. Standard protocols are available.

D. Arterial Thrombosis: Arterial thrombosis in newborns is almost always iatrogenic, secondary to arterial catheters. In newborns umbilical arterial catheters and peripheral arterial catheters are commonly used for monitoring purposes.

158

The incidence of arterial TEs secondary to catheters is related to: - catheter length - catheter diameter - catheter material - duration in the artery Common presentations include: - loss of patency of the catheter - prolonged capillary refill time - diminished or absent pulses - cool and pale limbs - necrotising enterocolitis (umbilical arterial catheters) - hypertension (umbilical arterial catheters) Arterial TEs may need urgent attention, as there is potential risk of organ or limb loss. Long term consequences (depending on the site) of arterial TEs include: - claudication - asymmetric limb growth - hypertension - impaired renal function

E. Diagnosis: - The "gold standard" diagnostic test is contrast angiography, although it may not be practical in critically ill -

newborns Doppler US is the most commonly used non invasive method which has variable sensitivity Especially for peripheral arterial thrombosis diagnosis is made on clinical grounds.

F. Treatment: - Remove catheter - Therapy with ultra fine heparin or low molecular weight heparin is most commonly used (dose and monitoring is the same as for VTE ) Consider thrombolytic therapy if potential loss of limb or organ Thrombectomy may be an option if viability of limb is threatened. Plastic surgery consultation is advised It is important to monitor the course of arterial and venous TEs.

-

G. Outcome: Mortality is highest among newborns with aortic thrombosis and those with right atrial or superior vena cava thrombosis. Always consult a Paediatric Haematologist.

H. Further Reading: •

Andrew M, Monagle P, Brooker L. Thromboembolic complications during infancy and childhood.Hamilton, BC Decker Inc; 2000.

66. TRACHEO-OESOPHAGEAL FISTULA/OESOPHAGEAL ATRESIA A. B. C. D. E. F. G.

Summary Introduction Associations Investigation Management Areas of Uncertainty in Clinical Practice References

A. Summary: -

early diagnosis is important to minimise pulmonary complications regular, thorough suctioning of the upper oesophageal pouch is required prior to definitive surgical repair referral to a level III neonatal surgical unit and the neonatal transport service should be made as soon as possible

159

B. Introduction: The aetiology of tracheo-oesophageal fistula (TOF) is not known. Disruption during development of the embryonic trachea and oesophagus in the fourth week of fetal life results in the persistence of fistulas between them and may result in incomplete oesophageal development. The incidence of oesophageal atresia (OA) is approximately 1 in 3000 to 4500 births. These infants are more likely to be premature because of the high association with polyhydramnios. In the most common variant of the disorder (approximately 86% of cases) the upper oesophageal segment ends in a blind pouch with a fistula connecting the distal oesophageal segment to the trachea, at or close to the carina. The uncommon variants include OA without a fistula, TOF from the proximal oesophageal pouch and isolated (H-type) TOF. The first clinical sign of OA is that of excessive oral secretions. Choking and regurgitation accompany feeding. Abdominal distension (due to air transmitted through the distal fistula), aspiration of secretions from the upper pouch and reflux of acidic gastric contents via the fistula to the lungs may all contribute to respiratory compromise. The infant with H-type TOF may present insidiously but usually coughs and chokes with feeding.

C. Associations: -

congenital heart disease, intestinal atresia, imperforate anus, skeletal anomalies and renal anomalies suggest the VACTERL association: Vertebral, Anal, Cardiac, Tracheal, ‘Esophagus’, Renal and Limb oesophageal atresia may also be seen in the CHARGE association: Coloboma, congenital Heart disease, choanal Atresia, growth and mental Retardation, Genital hypoplasia, Ear anomalies

D. Investigation: Diagnosis may be suggested on antenatal ultrasound with polyhydramnios (present in approximately 60% of cases) or the failure to detect the foetal stomach. If the diagnosis is suggested antenatally, or there are clinical signs at birth, an attempt should be made to pass a firm suction catheter or feeding tube (size 10F is adequate) to the stomach before the first feed. The inability to pass the tube into the stomach confirms the diagnosis of OA. Most often the tube comes to a halt at about 9 to 13cm from the gums (although this will depend on the size and gestation of the baby). A smaller, softer tube may curl up in the upper oesophageal pouch giving a false negative result. A chest and abdominal X-ray taken with the catheter tip in the pouch will confirm the position of the upper oesophageal pouch and air within the bowel confirms the presence of a distal tracheo-oesophageal fistula. Contrast in the upper pouch is usually not required. The absence of air below the diaphragm excludes a distal fistula. If an H-type TOF is suspected this is usually revealed by a contrast swallow. Echocardiography will be required to exclude cardiac anomalies and to establish the position of the aortic arch. Renal ultrasound should be performed if the neonate is anuric to exclude bilateral renal agenesis (although the baby would be expected to be in extremis from respiratory failure secondary to pulmonary hypoplasia) or severe dysplasia as this may preclude surgical intervention. It should also be considered if there are other features suggesting the VACTERL association.

E. Management: The neonate must be kept nil by mouth, commenced on intravenous fluids and nursed supine in a head up position (approximately 30 to 60 degrees). The upper pouch must be kept clear of secretions by frequent suctioning. Antibiotics are recommended if there is evidence of aspiration pneumonia. The patient should be transported to a level III surgical neonatal unit as soon as possible. In most cases early primary surgical repair is appropriate. The presence of coexisting severe anomalies or extreme prematurity may impact on the likelihood of survival.

F. Areas of Uncertainty in Clinical Practice: Some neonatal units recommend that all babies have a small nasogastric tube (e.g. size 5) passed down each nostril and into the stomach soon after birth so that most cases of OA and choanal atresia can be detected before the first feed. However, this practice is not universally accepted.

G. References: •

Avery, G.B., Fletcher, M.A., and MacDonald, M.G. (editors). Neonatology: Pathophysiology and Management of the Newborn. 5th edition. Lippincott, Williams & Wilkins. 1999.

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• • •

Levene, M.I., Tudehope, D.I., and Thearle, M.J. Essentials of Neonatal Medicine. 3rd edition. Blackwell Science. 2000. Hutson, J.M., Woodward, A.A., Beasley, S.W. (editors). Jones’ Clinical Paediatric Surgery, Diagnosis and management. 5th edition. Blackwell Science Asia. 1999. Ashcraft, K.W., Murphy, J.P., Sharp, R.J., Sigalet, D.L., Snyder, C.L. (editors). Pediatric Surgery. 3rd edition. W.B. Saunders Company. 2000.

Other Reading: •

Moss, R.L. (editor). Case Studies in Pediatric Surgery. McGraw-Hill. 2000. [Case 46: A term infant with excessive salivation]

67. TRANSFER GUIDELINES A. Summary B. Introduction C. Level 1: 1. Newborn Problems 2. Nursery Equipment Requirements D. Level 2: 1. Low Dependency Level 2 Newborn Problems 2. Equipment Requirements 3. High Dependency Level 2 Newborn Problems 4. Equipment Requirements E. Level 3: 1. Newborn Problems F. Essential Resuscitation Equipment G. Intubation Equipment

A. Summary: -

for infants expected to require treatment in a level 2 or level 3 institution, maternal transfer prior to delivery is usually wiser than a postnatal transfer exceptions apply where the pregnancy complication is of such a severe degree that any delay in delivery would jeopardize the survival or quality of survival of the infant or mother, or where delivery might occur during the transfer all delivery room and nursery equipment should be in good order at all times and readily available for use

B. Introduction: Every hospital providing newborn care services should develop guidelines regarding:

-

newborns for whom they can provide continuing care relationships with regional centres in order to facilitate care for those needing more complex levels of care

Guidelines must be flexible enough to take into account variation from time to time in availability of facilities and staff; each hospital will need to make its own assessment of its capabilities. The following are guidelines developed for use in Victoria regarding provision of care and equipment standards. Resuscitation and intubation equipment is required in all hospitals and staff should be competent in using the equipment.

C. Level 1: 1. Newborn Problems:

-

uncomplicated: • gestation 37 weeks or greater • birthweight > 2500 g emergency stabilization after resuscitation minor conditions not requiring additional nursing or specialist medical treatment phototherapy - with paediatric consultation some simple convalescent infants eg gavage feeding

161

2. Nursery Equipment Requirements:

-

high flow oxygen meter high flow air meter or oxygen diluter oxygen headbox oxygen analyzer incubator perspex cot bubble plastic/plastic cling wrap low reading thermometer blood glucose monitor scales oxygen saturation monitor (pulse oximeter) with neonatal probe

Optional:

-

constant infusion pump for neonatal use ambient temperature monitor phototherapy unit

D. Level 2: 1. Low Dependency Level 2 Newborn Problems:

-

as for level 1; in addition uncomplicated: • gestation 34 weeks or greater • birthweight 2000 g or greater incubator care short term transitional problems e.g. oxygen requirement up to 40% infants in need of • simple apnoea monitoring • blood glucose monitoring • short term intravenous therapy • phototherapy • gavage feeding

2. Equipment Requirements: As for Level I and: - apnoea monitor - constant infusion pump for neonatal use - heater and humidifier for inspired gases - low flow oxygen meter Optional:

-

external temperature monitor cardio-respiratory monitor non-invasive blood pressure monitor mechanical ventilator

3. High Dependency Level 2 Newborn Problems:

-

as for level 1 and Low Dependency level 2; in addition uncomplicated: • gestation 32 weeks or greater • birthweight 1300 g or greater other sick infants eg oxygen requirement up to 60% infants in need of • cardiorespiratory monitoring • intra-arterial blood gas monitoring (short term)

162

• • •

-

non-invasive blood pressure monitoring close observation eg neonatal abstinence syndrome short-term ventilator care pending transfer (less than 6 hours) special services: • Availability will vary between hospitals, not all units will have protocols established to provide all services and protocols must be consistent with relevant guidelines. Where provided, services should be undertaken following consultation with a tertiary centre. ƒ nasal CPAP ƒ exchange transfusion

4. Equipment Requirements: As for Level 2 Low Dependency and: - radiant heater with servo control - heater and humidifier for inspired gases - cardio-respiratory monitor - non-invasive blood pressure monitor - equipment for intra-arterial fluid administration and blood gas monitoring - conventional mechanical ventilator - low flow oxygen meter Optional: - external temperature monitor - transcutaneous oxygen/carbon dioxide monitor - incubator with servo-control

E. Level 3: 1. Neonatal Problems:

-

as for Level 1 & 2; in addition to all Neonatal Intensive Care

F. Essential Resuscitation Equipment: - resuscitation cot with overhead radiant heater or resuscitaire. - clock (with second hand). - overhead lighting - pre-warmed linen - at least two wraps to receive newborn - paediatric stethoscope - oxygen supply: cylinder in use and spare cylinder readily accessible - 6 Fr. Intranasal oxygen catheter - self-inflating bag (Laerdal Infant Resuscitator or anaesthetic bag and circuit) with pressure gauge attached -

and spare resuscitator face masks of appropriate size (0/1 and spare) suction apparatus with pressure gauge "Y" suction catheters sizes:- 6, 8, 10 Fr. intubation equipment (see below) umbilical venous catheterization tray and additional equipment needles and syringes, eg 19, 21, 23, 25 G and 1mL, 2mL, 5mL, 10mL, 20mL syringes butterfly needles eg 21 and 23 G (for emergency pneumothorax drainage) alcohol swabs resuscitation drugs:

Sodium bicarbonate 8.4% 10mL ampoules x4 Sterile water for injection

10mL ampoules x4

Naloxone 0.4mg/Ml

2mL ampoules x2

Adrenaline 1 in 10,000

10mL ampoules x2

Sodium chloride 0.9%

5mL & 10mL ampoules x4 163

G. Intubation Equipment: -

laryngoscope with suitable sized blade for preterm/term neonate: • Handle: Penlon miniature with hook-on fitting • Blades: Miller 0 (Premature), Seward 1 (Neonatal) introducer (in sterile package) magills forceps (used for nasal intubation) endotracheal tubes: Sizes 2.5, 3.0 and 3.5mm connectors to fit between ET tubes and ventilation system tapes for securing ET tubes - Sleek "trousers", Leukoplast, cotton tie skin prep swabs cotton buds

68. TRANSFUSION A. B. C. D. E. F.

Introduction When to transfuse Complications Investigation Acute Blood Loss Areas of Uncertainty in Clinical Practice

A. Introduction: Red blood cell (RBC) transfusions in neonates are used to treat - acute blood loss and shock secondary to hypovolaemia - anaemia of prematurity, secondary to • Delayed and reduced RBC production • Shortened RBC survival • Rapid postnatal growth • Iatrogenic loss from frequent blood sampling for laboratory monitoring - hyperbilirubinaemia (double volume exchange transfusion) This topic concentrates predominantly on the second scenario.

B. When to transfuse: There are no simple clinical or laboratory indicators of necessity for blood transfusion. There is no known critical haemoglobin (Hb) or haematocrit (Hct) level required to maintain tissue oxygenation and many factors (including Hb and RBC in oxygen transport, the proportion of fetal and adult Hb, the level of 2,3-DPG, arterial oxygen tension, cardiac output) are involved. In addition, there is no good quality evidence to support any significant benefit of transfusion on: - poor weight gain - recurrent apnoea - poor feeding - tachypnoea - tachycardia

C. Complications: There are many potential adverse effects of RBC transfusion. These include: - volume overload - immunosensitisation - graft versus host disease - metabolic derangements (hyperkalaemia, hypocalacaemia) - transmission of infection (per million donations): • HIV (0.79) • hepatitis C (4.27) • hepatitis B (2.71) - NEC

164

Therefore RBC transfusion should be avoided, or if necessary the risk minimised by:

-

using guidelines for RBC transfusion. Although based on small studies and consensus derived from a panel of experts (low quality evidence), RBC transfusion guidelines can significantly reduce the number and volume of RBC transfusions. reducing donor exposure by the use of pedipacks using leucocyte reduced RBC with leucocyte depletion filter using CMV negative or reduced blood with leucocyte depletion filter using irradiated blood for directed donor transfusions. However, there is no evidence that transfusion with direct donor blood is safer for neonates and the process takes 5 working days.

D. Investigation: -

Hb, Hct, reticulocyte count ABO and Rh grouping of baby and mother

E. Management: Guidelines for RBC transfusion might include: - Hb <70 g/l or Hct <0.20 with reticulocyte count < 100 x109/l - Hb <90 g/l or Hct <0.25 with one or more of • significant apnoea or bradycardia (more than one episode of apnoea (link) or bradycardia per hour OR 2 episodes/24 hours requiring bag and mask ventilation) • sustained heart rate > 180/min or respiratory rate >80/min for 24 hours • weight gain < 10gm/day over 4 days while receiving > 120 kcal/kg/day • mild respiratory distress with oxygen requirement < 35% not requiring respiratory support - Hb <100 g/l or Hct <0.30 if : • requiring any respiratory support • oxygen requirement > 35% - do not transfuse: • to replace blood removed for laboratory testing • for low Hb or Hct alone Parents must be informed of the need to transfuse a stable preterm infant. Transfuse 20 ml/kg of packed RBC over 4 hours. Infants with critical circulatory status may require frusemide 1mg/kg mid-way through transfusion

F. Acute Blood Loss: Transfuse with whole blood or packed RBC 20 ml/kg or estimated volume of blood loss titrated to infants response to transfusion. This should be given over 30 minutes.

G. Areas of Uncertainty in Clinical Practice: The precise indications for and clinical benefits of RBC transfusion remain controversial. There is currently a large multicentre international trial (PINT) underway in Melbourne addressing this issue.

H. References: • • •

Ramasethu J, Luban LC. Red blood cell transfusions in the newborn. Semin Neonatol 1999;4:5-16 Fetus and Newborn Committee, Canadian Paediatric Society. Guidelines for transfusion of erythrocytes to neonates and premature infants. Can Med Assoc J 1992;147:1781-6 Blanchette VS, Hume HA, Levy GJ, et al. Guidelines for auditing pediatric blood transfusion practices. Am J Dis Child 1991;145:787-96

Other Reading/Web links: • •

Ramasethu J, Luban LC. Red blood cell transfusions in the newborn. Semin Neonatol 1999;4:5-16 RPA Newborn Care

165

69. TUBERCULOSIS (TB) A. Diagnosis B. Management C. References Tuberculosis is prevalent in most tropical developing countries and constitutes a special risk during pregnancy and lactation to mothers and infants. Mortality from TB is highest in patients less than 5 years of age.

A. Diagnosis: 1. Congenital T:

-

-

exceedingly rare the placenta may be infected resulting in severe fetal involvement and fetal death transplacental infection usually occurs when the pregnant woman has clinical tuberculosis or a recent primary infection. Placental TB can spread to the foetus by the umbilical vein. The primary complex may be in the foetal liver, gastrointestinal tract, or mesenteric nodes. A placental tubercle may rupture causing tubercular amnionitis and possible foetal aspiration with primary complex in the foetal lung the infant may aspirate infected secretions at the time of birth postnatal exposure from the infected mother or other infected family members

2. Maternal Tuberculosis: Identification and treatment of maternal TB is the most efficient method of preventing TB in the newborn. Skin testing should be done on pregnant women who are: - suspected of exposure - have increased susceptibility to acquire TB - live in high prevalence area - workers with a high probability of exposure There is no significant increase in malformations for infants born to infected mothers on treatment. There is no indication for therapeutic abortion.

3. Clinical features: Clinical features may be present at birth or not until 8 weeks of age. The mean time of onset is 2-4 weeks. These include: - respiratory distress - fever - hepatic and splenic enlargement - irritability, poor feeding and lethargy - lymphadenopathy - skin papules - failure to thrive - jaundice - biliary obstruction

4. Investigation: A PPD tuberculin skin test (5 Units) should be performed on any infant suspected of having congenital or perinatally acquired infection. However, it may not be positive unless the infection has been present for 4-6 months. If direct smears are negative but the infant is ill, antituberculosis therapy should be given until the diagnosis is ruled out.

B. Management: - Suspected congenital TB:

-

Mantoux test (5TU-PPD), chest x-ray, lumbar puncture, and cultures are taken. The infant should then be started on therapy regardless of the skin test results. Treatment should include INH, RIF and pyrazinamide until the drug sensitivity of the infant or mother’s isolate is known. Since neonates are at greater risk of developing extrapulmonary tuberculosis they are initially treated as for tuberculosis meningitis with INH, RIF, pyrazinamide and sometimes streptomycin for 1-2 months. Once sensitivities are known treatment should include two bactericidal drugs of appropriate sensitivities. Mother on treatment with active disease: Anyone with active disease who is in contact with the infant should use a face mask until sputum is demonstrated as organism free. The infant is treated with INH and PPD skin test performed. BCG vaccine should be considered if there is concern about compliance.

166

-

-

Mother on treatment without active infection: Infant is at some risk even if the mother's sputum is negative. The infant should be treated with INH for 4 months and should have skin test done at 4 month of age. If skin test on infant is negative and contacts are not infectious, INH can be stopped. The skin test on the infant should be repeated at 6, 9, and 12 months. If the skin test is positive, the baby should have a chest x-ray and further investigations for TB while continuing INH. Nursery exposure: Spread can occur from infected infants or personnel. If exposure is significant, infants should be tested with 5 units of PPD and, if negative, treated with INH 10 mg/kg/day for 3 months. The skin test should then be repeated and if it is still negative therapy stopped.

C. References: • • •

American Academy of Pediatrics: Chemotherapy for tuberculosis in infants and children.Pediatrics 89:161, 1992. Vellejo, J. G. Clinical features: Diagnosis and treatment of tuberculosis in infants. Pediatrics 94:1,1994. Smith, M. H. D., and Teele, D. U. Tuberculosis. IN: J. S. Remington and J.O. Klein (Eds), Infectious diseases of the fetus and newborn infant (4th Ed.). Philadelphia: W.B. Saunders, 1995.

70. UMBILICAL ARTERY CATHETERIZATION A. B. C. D. E. F. G.

Indications Equipment Procedure Ongoing Management Complications Catheter Removal References

A. Indications: - acid-base and oxygen monitoring - blood sampling for other investigations - continuous arterial blood pressure monitoring B. Equipment: Arterial tray:

-

1 scalpel blade handle 2 probes: fine and medium 4 mosquito artery forceps: 2 curved, 2 straight 2 pair dissecting forceps: toothed, non-toothed 2 iris forceps 1 pair vein scissors 1 pair suture scissors 1 needle holder 2 bowls cotton wool swabs gauze swabs tape measure

Other equipment:

-

surgical mask sterile gown and gloves 1 plastic drape (sterile) 1 scalpel blade No. 11 1 umbilical artery catheter • Fg 3.5 < 1250g baby • Fg 5 > 1250g baby 1 blood pressure monitoring kit 1 disposable leur lock 3-way tap 1 x 5ml syringe and 18G needle 1 x 10ml ampoule 0.9% saline

167

-

1 packet 3/0 black silk suture Skin preparation solution - aqueous chlorhexidine and povidone iodine Parenteral administration set Infusion pump Ordered parenteral solution 1ml ampoule heparin 1,000 units/ml drug additive label 2cm wide leukoplast for taping of catheter

C. Procedure: - estimate the position of catheter tip: •

-

-

-

-

-

the correct position is in the descending aorta above the origin of the mesenteric and renal arteries (to avoid occlusion in these vessels) • the catheter length maybe calculated from the formula [ Weight (kg) x 3] + 9cm • remember to add the length of the cord stump flush the selected catheter via the 3-way tap with normal Saline. Leave the syringe of saline attached to 3way tap throughout the procedure clean the umbilical stump and surrounding 3-4cm of abdomen with povidone iodine. Wait 2 minutes. Clean the area with aqueous chlorhexidine drape around the umbilical stump with sterile towels tie a short piece of rolled gauze around the base of the cord. It should be secure enough to maintain haemostasis but not too tight to prevent passage of the catheter with a pair of straight forceps, grasp the end of the cord clamp and pass the forceps to the assistant. Whilst the assistant applies gentle upward traction, slice the cord with the scalpel, 1-1.5cm from the skin margin. An alternative method is to leave the cord long and cannulate the artery from the side. This method should be left to experienced operators only when the cut surface is blotted dry, the umbilical vessels can be identified: • the single thin walled umbilical vein • two smaller thick walled round arteries, generally constricted so that their lumen appear pinpoint. They often protrude from the cut surface of the umbilical cord to insert the arterial catheter the orifice of the artery is gently opened with fine forceps. . Initially 1 tip and then both tips of the iris forceps should be gently inserted into the artery. The tips should be allowed to spring apart. The tips should be gradually advanced to the curve of the forceps. Then the vessel may be cannulated. Obstruction may be encountered at the anterior abdominal wall or bladder. This can usually be overcome by 30-60 seconds of gentle, steady pressure. Avoid excessive pressure or repeated probings. If unsuccessful, seek advice from a more experienced person. The most common error arises after cannulating the layer between the vascular intima and the muscle. This usually occurs if dilatation of the artery in the cord has been inadequate ensure patency of catheter by checking for easy withdrawal of blood and "pulsation" of blood/saline in the catheter secure catheter with 3/0 black silk suture by placing a purse string suture (use several small bites) around the base of the cord. Do not include the skin. Commence the suture close to the catheter so that the first knot lies at the base of the catheter. Tighten the purse string and knot securely. Tie the purse string around the catheter tightly connect catheter to infusion fluid confirm the position of catheter by X-ray check for arterial waveform on arterial transducer after it is connected and calibrated

D. Ongoing Management: - observe skin colour

-

Note any skin blanching or bruising of limbs, toes or buttocks prior to procedure, during and following the procedure, and at any time that catheter is in situ. Report immediately. If one limb is involved, warm opposite limb to induce reflex vasodilation of affected limb. If physical therapy fails, the catheter may be withdrawn 0.5 - 1cm and observe. Remove catheter if blanching persists >30 minutes. maintain infant supine or in lateral position for 24 hours post procedure to observe for haemorrhage from umbilical stump keep catheter and infusion line clear of blood as blood clots may form. Remove all air bubbles in the infusion line and catheter. Interruption to infusion must be for as short a time as possible. Do not flush catheters quickly filters are not used for IA lines. All connections must be luer lock

168

E. Complications: - bleeding due to accidental disconnection, or from open connections - vasospasm of the femoral artery causing blanching of toes and foot is less common with high than low -

-

catheters. The opposite limb may be warmed with a warm moist towel. If blanching persists, the catheter must be removed embolisation from blood clot or air in the infusion system thrombosis - may involve: • femoral artery resulting in limb ischaemia, gangrene • renal artery resulting in hypertension, haematuria, renal failure • mesenteric artery resulting in gut ischaemia, necrotising enterocolitis vascular perforation of the umbilical arteries, haematoma formation and retrograde arterial bleeding infection - prophylactic antibiotics are not required

F. Catheter Removal: - equipment required: • • • • •

-

alcohol swab sterile stitch cutter (optional) sterile blade specimen container tapes the procedure is performed by medical staff clean the stump with an alcohol swab turn infusion pump off and clamp infusion line remove sutures and withdraw catheter to within 3-4cm of skin tape catheter to skin and maintain infant supine wait for pulsation in catheter to stop (this usually takes 10-20 minutes) remove rest of catheter. If any bleeding is noted, apply positive pressure below level of stump only send tip for culture and sensitivity if infection is suspected do not nurse infant prone for 4 hours following removal. Observe for bleeding

G. References: •

Umbilical Artery Catheterisation Protocol, Southern Health Care Network -Monash Medical Centre, Newborn Services

71. UMBILICAL CORD CARE A. B. C. D. E.

Introduction Routine Care Nursery Care Areas of Uncertainty References

A. Introduction: 6

Aseptic practice has reduced the rates of omphalitis, neonatal tetanus and sepsis. The practice of separating mothers and babies in the 1940's associated with prolonged hospital stays led to a steep rise in nosocomial infections. To control this problem routine application of antimicrobial agents to the cord stump became common. However, current evidence supports the use of standard infection control procedures only, in this area of practice.

B. Well baby care: -

clamp the cord with sterile clamps and cut it with sterile scissors or blade the recommended length of the stump after cutting is 2 or 3 cm practice rooming in where possible, with the mother as primary carer keep the cord dry and exposed to air. The napkin should be folded below the umbilicus wash hands before handling the umbilical cord and where possible avoid touching the cord stump remove the cord clamp on day 2 of life

169

C. Nursery Care: -

practices vary between hospitals because of a lack of relevant high quality evidence with care being either: • as for routine care • or a solution of 0.5% Chlorhexidine and 70% alcohol is used to clean the cord twice daily on admission and daily for the first three days, or while an umbilical catheter is in situ

D. Areas of Uncertainty: -

-

a study comparing daily bathing with no bathing showed no difference in umbilical cord colonization or infection between the groups, and that immersing the newborn in a bath is not harmful to the cord when reviewed for the Cochrane database use of topical antiseptics for routine care was associate with • no systemic infections or deaths • a trend to reduced colonisation with antibiotics compared to antiseptics • prolonged cord separation time • no effect on cord or other skin infections within 6 weeks with use of antiseptics there is a lack of studies concerning effects on the rate of umbilical cord infections for infants requiring nursery admission. Some non-randomized studies have suggested that antiseptics reduce staphylococcal infections in the nursery and after discharge various agents have been used as topical antimicrobials for umbilical cord care with a variety of complications: • alcohol is a bactericidal agent with limited effectiveness if not correctly applied • chlorhexidine is a bactericidal agent (some pseudomonas and proteus may be resistant). Skin sensitivity has occasionally been reported. Percutaneous absorption has been found with the use of a 1% solution in ethanol • iodine tincture is bactericidal, sporicidal, cysticidal and virucidal. Action persists for several hours and toxicity is low • iodophors - iodine is absorbed through the skin and its use has been associated with transient hypothyroidism • triple dye has been shown to effectively reduce colonisation by MRSA but ineffective for GBS. It is a combination of brilliant green, proflavine hemisulfate and gentian violet • crystal violet has been associated with necrotic skin reactions in adults and babies. Sensitization to brilliant green has been reported • silver sulphadiazine may cause bacterial resistance to sulphonamide and allergic reactions

E. References: •

•

Zupan J, Garner P. Topical umbilical cord care at birth (Cochrane Review). The Cochrane Library, 2, 2001. Oxford World Health Organization, Reproductive Health (Technical Support) Maternal and Newborn Health/Safe Motherhood, Geneva. Care of the Umbilical Cord, A review of the evidence1999 Dore, Sharon et al. Alcohol Versus Natural Drying for Newborn Cord Care. JOGGN Vol 27(6) November/December 1998.

Web links: •

www.who.int/rht/documents/ www.cochrane.org

72. UMBILICAL HERNIAS A. B. C. D. E. F.

Summary Introduction Differential Diagnosis Investigation Management References

A. Summary: - uncomplicated umbilical hernias may be safely observed in the first few years of life, with spontaneous -

regression occurring in most cases serious complications are rare

170

B. Introduction: Umbilical hernias are common in the neonatal period and represent a central fascial gap beneath the umbilicus through which abdominal contents may protrude, covered by skin. This gap is a consequence of delayed contraction of the encircling fibromuscular umbilical ring. They are more common in: - preterm infants - Down syndrome - increased intra-abdominal pressure (eg ascites) - congenital hypothyroidism Although the hernia may be prominent with straining or crying it should be easily reducible. Incarceration, strangulation and evisceration are rare complications.

C. Differential Diagnosis: - paraumbilical hernias (usually sited just above the umbilicus) require surgical review - exomphalos (herniation of viscera into the base of the umbilical cord covered by fused amniotic -

membrane and peritoneum) requires urgent surgical referral epigastric hernia (presents as a tender lump in the midline of the epigastrium)

D. Investigation:

No investigations are required in uncomplicated cases.

E. Management: Most children with an umbilical hernia require no intervention. Although some may initially increase in size over the first few months of life over 90% will have closed by 2 years of age. Surgery beyond this age is usually on cosmetic grounds although the risk of incarceration is increased in adulthood. Dressings to cover the hernia (eg coins, strapping) are ineffectual and may traumatise surrounding skin.

F. References: • • •

Avery, G.B., Fletcher, M.A., and MacDonald, M.G. (editors). Neonatology: Pathophysiology and Management of the Newborn. 5th edition. Lippincott, Williams & Wilkins. 1999. Hutson, J.M., Woodward, A.A., Beasley, S.W. (editors). Jones’ Clinical Paediatric Surgery, Diagnosis and Management. 5th edition. Blackwell Science Asia. 1999. Ashcraft, K.W., Murphy, J.P., Sharp, R.J., Sigalet, D.L., Snyder, C.L. (editors). Pediatric Surgery. 3rd edition. W.B. Saunders Company. 2000.

73. UMBILICAL VEIN CATHETERISATION A. B. C. D. E. F. G.

Summary Introduction Equipment Required Procedure Catheter Complications Catheter Removal References

A. Summary: infants < 800gm should have a UVC as the initial preferred venous access. Preferred catheter tip placement is at the level of the diaphragm: - throughout insertion, the catheter must be kept filled with fluid and a closed 3-way tap attached. If the infant takes a deep inspiration negative pressure may be generated and air drawn into the catheter which could result in air embolism - the best location of the catheter tip is in the inferior vena cava above the diaphragm or just inside the right atrium. Placement of the catheter tip in the portal circulation is not acceptable. The position must be checked by X-ray - during an emergency, umbilical venous access is acceptable in the short term as a route for resuscitation drugs and fluids with the catheter tip inserted only 3 - 5cm beyond the muco-cutaneous junction (in this situation the catheter will no thave reached as far as the portal circulation)

B. Introduction: - during the first 7 -10 days of life the umbilical vein is a convenient route for obtaining vascular access -

during emergencies when establishing peripheral venous access is technically difficult (it is the initial route of choice for the tiny infant) as a route for central venous pressure monitoring (in the NICU)

171

C. Equipment Required: - sterile gloves and gown - instrument pack (as for umbilical artery catheterisation) and sterile drape (transparent plastic is preferred -

-

for better patient visualisation) antiseptic to prepare the skin umbilical catheter: • a single lumen catheter (FG3.5 < 1000gm, FG5.0 >= 1000gm) is recommended. If unavailable, a feeding tube (size 5) can be used • multiple lumen catheters are sometimes used in extremely sick or premature infants in the NICU syringe with NaCl 0.9% flush routine IV line tubing set-up and tape

D. Procedure: - observe universal precautions - place infant on open heated cot - monitor the infant (saturation and cardiorespiratory) and ensure all four limbs are adequately restrained -

throughout the procedure open an atraumatic suture (5 0 silk on cutting edge needle) if using an infusion, check solution is correct and prepared to the stage where it can immediately run into the catheter select appropriate catheter, usually 5 Fr. or 3.5 Fr. if infant weighs below 1000 grams the catheter must be attached to a syringe and filled with infusion solution before insertion prepare umbilicus, cord and cord clamp with iodine solution, cut the umbilical cord about 1.5 cm from the abdomen, and establish sterile field insert a purse-string suture near base of Wharton's jelly for haemostasis. Tie a single knot immobilize cord by two artery forceps at 3 and 9 o'clock, grasping cord edges insert tip of iris forceps into lumen, allow the forceps to spring open when blood is in catheter, connect up the two way tap to the infusion and flush catheter gently tie purse string and tie onto catheter or secure to catheter with tape. Make certain fluid type and rate is specified write out the x-ray request and be sure to inspect the x-ray later routine heparinization of umbilical venous catheters is not recommended

E. Catheter Complications: - infection - bleeding due to disconnection of tubing. Always use a Luer locked connection when attaching the catheter -

to infusion lines perforation - never cut off the rounded end of any indwelling catheter clot formation, embolism and spasm effects of catheter malpositioning include cardiac arhythmias, hepatic necrosis or portal hypertension avoided by checking catheter positioning by X-ray

F. Catheter Removal: - performed by medical staff - turn infusion off - withdraw catheter gradually as a single procedure - send tip for culture only if infection is suspected - if bleeding occurs press firmly just above the umbilicus - do not nurse the infant in the prone position during removal of the catheter and for the immediate 4 hours after removal

G. References: • •

Umbilical Vein Catheterisation Protocol, Southern health Care Network -Monash Medical Centre, Newborn Services Stabilization and Transport of Newborn Infants and At-risk Pregnancies, 4th Edition, 1998,Editors E.D.Bowman, S.M.Levi, A.J.Mclean, F.E.Presbury NETS publication

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74. UNDESCENDED TESTES (CRYPTORCHIDISM) A. B. C. D. E. F.

Summary Introduction Differential Diagnosis Investigation Management References

A. Summary: - refer to surgical services if a palpable UDT fails to descend by 3 months of age or the testis is non-

palpable exclude the diagnosis of ambiguous genitalia

B. Introduction: Undescended testes (UDT) is a common finding in the neonatal period affecting up to 1 in 20 term males and up to one third of preterm males. In most cases the aetiology is unknown. The risk of infertility and of testicular malignancy is increased in men with a history of UDT. The UDT is also more vulnerable to trauma and torsion. Histologic changes in the uncorrected UDT are seen at approximately 18 months to 2 years. If at term the testes are normally sited, deep in the scrotum, the infant is unlikely to develop true acquired cryptorchidism. The UDT may be best classified as palpable or non-palpable. The non-palpable testis is uncommon (less than 10%) with approximately half of these atrophic. The palpable UDT should be defined by the lowest point to which it can be mobilised, with most cases being palpable in the groin. If a testis is not readily identified a finger sweep should be performed from the anterior iliac crest along the inguinal canal whilst palpating the scrotum. The normal testicular volume at term is 1-2cm3.

C. Differential Diagnosis: - UDT in association with severe hypospadias must be assessed for congenital adrenal hyperplasia -

and

other causes of ambiguous genitalia (approximately 25% of neonates with undescended testes and hypospadias have ambiguous genitalia) an ectopic testis (ie has not followed the normal path of descent) is rare and should be referred for surgical review

D. Investigation: - imaging studies are rarely of use in identifying a non-palpable UDT - immediate referral and further investigations are necessary if undescended testes are associated with ambiguous genitalia

E. Management: Failure to descend by approximately 3 months of life is considered abnormal and these infants should be referred for surgical opinion. The optimal time for orchidopexy is at about 6 to 12 months of age. This allows for further spontaneous descent but may reduce some of the sequelae of testicular non-descent. Although surgery to place the testis in the scrotum may not reduce the risk of infertility or malignancy it improves the endocrine function of the testis and facilitates testicular self-examination. It also reduces the risk of torsion and direct trauma. Surgical exploration (laparoscopy) for the non-palpable testis is warranted as in approximately half of these cases the testis may be salvaged. In the remainder the testis is absent or a testicular remnant with neoplastic potential may be removed. Absence of both testes (anorchia) is rare.

F. References: • • • •

Avery, G.B., Fletcher, M.A., and MacDonald, M.G. editors. Neonatology: Pathophysiology and Management of the Newborn. 5th edition. Lippincott, Williams & Wilkins. 1999. Hutson, J.M., Woodward, A.A., Beasley, S.W. (editors). Jones’ Clinical Paediatric Surgery, Diagnosis and Management. 5th edition. Blackwell Science Asia. 1999. Levene, M.I., Tudehope, D.I., and Thearle, M.J. Essentials of Neonatal Medicine. 3rd edition. Blackwell Science. 2000. Ashcraft, K.W., Murphy, J.P., Sharp, R.J., Sigalet, D.L., Snyder, C.L. (editors). Pediatric Surgery. 3rd edition. W.B. Saunders Company. 2000.

Recommended Reading/Web links: •

American Academy of Pediatrics; Timing of Elective Surgery on the Genitalia of Male Children With Particular Reference to the Risks, Benefits, and Psychological Effects of Surgery and Anesthesia. Pediatrics 1996;97:590-4 www.aap.org/policy/01306.html

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75. VOMITING IN THE NEWBORN INFANT A. B. C. D. E. F. G. H.

Introduction Vomit contains blood Vomiting bile Projectile vomiting Vomiting in the unwell baby Vomiting with failure to thrive Vomiting causing choking and aspiration The baby has concomitant diarrhoea

A. Introduction: Most babies vomit at some time. In most cases this is unimportant. However, there are circumstances when the type of vomiting is important. They are as follows: - vomit contains blood (red or black, the colour of the blood will depend upon how long the blood has been in the stomach) - vomiting bile (green, not yellow) - projectile vomiting - the baby is unwell - the baby is failing to thrive - the baby has gastrooesophageal reflux and could be aspirating - the baby also has diarrhoea - the abdomen is distended Where none of the above clinical scenarios apply the vomiting is unlikely to be clinically significant. Small, frequent vomits are referred to as "posits".

B. Vomit contains blood: The commonest cause is swallowed maternal blood. Swallowed blood often irritates the stomach and causes vomiting. Blood may be swallowed during: - birth - breast-feeding Birth. No delivery is bloodless, whether vaginal or Caesarean, and hence there is the opportunity to swallow blood at birth. However, the largest amount of blood will be swallowed if there is antepartum haemorrhage associated with bleeding into the amniotic fluid for at least several hours before birth. This blood may then take several days after birth to clear the gastrointestinal tract (GIT). Under these circumstances, as well as vomiting blood, the baby may pass malaena stools, rather than meconium. Breast-feeding. Many breast-fed babies will swallow blood from a cracked and bleeding nipple. Usually the mother is aware of the nipple problem, but not always, as the bleeding may be deeper and painless. Management of swallowed maternal blood is expectant. If it is swallowed from birth it will eventually clear from the GIT. The mother's cracked and bleeding nipple will require attention, and she may require lactation advice about nipple attachment. This becomes a transient contraindication to breast feeding if the mother is Hepatitis C positive. Less commonly, the baby is bleeding. Causes include:

-

haemorrhagic disease of the newborn (HDN) stress ulceration swallowed baby blood

HDN rarely occurs with adequate Vitamin K prophylaxis. Babies whose mothers have been taking medications that interfere with Vitamin K metabolism (e.g., anticonvulsants, oral anticoagulants), or babies with liver disease or consumption of clotting factors are at higher risk. Babies who are very sick can have stress ulceration of the stomach, as can those treated with drugs such as corticosteroids and indomethacin. Babies can swallow their own blood from upper airway trauma, as may occur from vigorous suctioning, endotracheal tube insertion or with difficulty passing a nasogastric tube.

-

some babies with gastro-oesophageal reflux can develop reflux oesophagitis, which may bleed

Usually the origin of the blood is clear from the history, but if there is doubt the laboratory can perform an Apt test (blood mixed with sodium hydroxide). This distinguishes fetal from adult haemoglobin.

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C. Vomiting bile: -

a baby who vomits bile (green, not yellow, in colour) should be presumed to have a bowel obstruction, until proven otherwise there are many causes of bowel obstruction , but the most potentially dangerous is volvulus related to malrotation of the midgut. The bowel can twist, become ischaemic and necrotic within a matter of hours, so the diagnosis and treatment are urgent Other signs of obstruction, including abdominal distention, and imperforate anus should be sought a supine abdominal X-ray will usually reveal an abnormal gas pattern (e.g., a paucity of gas and distention of the stomach and proximal duodenum in volvulus; more gaseous distention with lower obstructions), and a lateral decubitus X-ray will reveal fluid levels treatment includes urgent surgical referral, IV fluids and gastric drainage

D. Projectile vomiting: -

-

occasional projectile vomiting may occur without a specific cause in some neonates. duodenal obstruction should be considered. The commonest cause is duodenal atresia, in whom about half of the infants will have Down syndrome. However, duodenal atresia is more commonly diagnosed antenatally, in a mother who presents with polyhydramnios and in whom the classical "double-bubble" appearance (distention of stomach and first part of duodenum) is seen on ultrasound. If the diagnosis is not made antenatally, the baby may have minimal vomiting until the milk intake increases after the first few days of life. The diagnostic test is an abdominal X-ray, which reveals the classic "double-bubble" appearance. pyloric stenosis usually presents at 2-3 weeks of age, after most babies have been discharged home. However, it occasionally occurs in the convalescing preterm infant before discharge home. Ultrasound will often help to make the diagnosis.

E. Vomiting in the unwell baby: -

-

consider: • infection • inborn errors of metabolism • congenital adrenal hyperplasia helpful clues include: • other signs of sepsis (including NEC) • excessive weight loss (including dehydration) • disordered conscious state • metabolic derangements, including metabolic acidosis and electrolyte disturbances (high potassium and low sodium in congenital adrenal hyperplasia)

F. Vomiting with failure to thrive: -

-

causes of vomiting leading to failure to thrive include: • gastro-oesophageal reflux (GOR) • infection • inborn errors of metabolism GOR usually does not present in the first days after birth, probably because milk intakes are relatively low. Also it is usually much worse with any artificial formulas compared with breast milk, and most babies are at least initially breast-fed. Therefore most term babies present after discharge home GOR is most commonly diagnosed in nurseries in convalescing preterm babies the vomiting is characteristically effortless, and occurs more when the stomach is full (after a feed), and when the baby is lying flat, rather than when upright. Occasionally the vomit may contain blood from reflux oesophagitis in most babies the diagnosis is clinical and partly confirmed by response to anti-reflux measures. Where anti-reflux measures fail, further investigation is necessary for an exact diagnosis treatment includes thickening the baby's feeds, smaller, more frequent feeds, minimal handling after feeds, and occasionally elevation of the head of the cot preterm babies have less GOR when nursed prone, but they must be monitored electronically for apnoea rarely, persistent GOR requires fundoplication

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G. Vomiting causing choking and aspiration: -

-

all babies are capable of choking sometimes the choking follows vomiting. It is particularly common in the first day after birth, especially if the baby has swallowed any blood or meconium. It is also common when the milk flow is excessive, especially around 3-4 days of age. Most babies cope with these episodes quite well, and either swallow the regurgitated contents or cough them out recurrent aspiration is usually caused by severe GOR

H. The baby has concomitant diarrhea: -

-

gastroenteritis is less common during primary hospitalisation due to: • higher breast-feeding rates • more rooming-in (less care of babies in communal nurseries, where infectious agents such as rotavirus can spread easily) gastroenteritis can, however, still cause vomiting and diarrhoea in newborn infants, and cause dehydration and shock if unrecognised.

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