Respiratory Distress In A Newborn Premature <37 Weeks Gestational

Respiratory Distress in a Newborn Premature <37 Weeks Gestational Age Prematurity = ↑Mortality Rate (Males>Females) RDS common, Maternal Diabeties, Perinatal Asphyxia, low gestational age – RDS, Apnea, IVH, Infections, Hypothermia,Metabolic, GI, Renal, Hyperbilirubinemia Fetal Lung Development 1. Pseudoglandular stage 7-17th wk BranchingsAlveoli 2. Canalicular Stage 16-25wkpreviableviable lung TYPE II cellssurfactant 3. Saccular/Alveolar Stages 25-termViable baby Increasing SA for gas Exchange a. Post 26 weeks Lung SA/Volume Increases 4. Adolesence= lung growth Surfactant: made by Type II pneumocytes -dependant on pH, temp and perfusion SPA/SPD = Immunity SPB/SPC=Reduce Surface Tension Decreases Surface Tension of water, hydrophilic and hydrophobic Laplace’s Law: P = 2T/r Large Alveolus-low collapsing pressure; Small Alveolus-high collapsing Pressure Small Alveolus w/Surfactant= Low collapsing Pressure Air filled Alveolus requires more pressure to fill than Saline Filled Alveolus (air=hysteresis) Respiratory Distress Syndrome: Caused by Decrease production of Surfactant; Failure to Develop FRC and Alveoli tend to collapse. Hypoxia/Asphyxia/Hypovolemia could worsens infant’s condition Less compliance: Atelectasis, hyaline membrane formation, edema ↑Work of Breathing Abnormal V/Q Ventilation/Perfusion mismatches hypoxia Clinical Manifestations w/in minutes of birth: Tachypnea- Mechanical pulmonary dysfunction, acid base imbalance, blood-gas abnormalities, ↑breathing to ↓work (stiff lungs= fast + shallow; increased resistance slower + deeper) Grunting- expiration through partially closed vocal cords ↑Tp in absence of airflow ↑V/Q increased airway pressure and lung volume Intercostal/subcostal retractions↑Accessory muscles of respiration due to less compliant lungs Nasal Flaring- Infants nose breathers, nasal resistance contributes to airway resistance (↑R) Cyanosis- Ficks law of Diffusion = Chance P*SA*permeability/ membrane thickness sqrt MW Natural Course: *Peaks at 3 days then gradual improvement if infant survives*Progressive worsening of cyanosis/distress/ Bp falls/ fatigue/ pallor /apnea/ irr. Resp./ acidosis Diagnosis: CXR (reticular granularity), Lab: Hypoxemia, Hypercapnemia, metabolic acidosis Treatment: Exogenous Surfactant Administration Prematurity- maintain core, reduce O2 consumption, IV fluids, glucose, electrolyes Inadequate exchange O2/Co2- warm humidified pO2 55-75mmHg 90% sats; mechanical ventilation, antibiotics Treat Circulatory insufficiency and Metabolic Acidosis Monitor HR/Respiratory rate/ BP, Fluids/ Electrolytes Complications: Chronic Lung Disease; BPD; result of long injury in infants requiring O2/mechanical vent. Recover by a year, Rt sided heart failure Pneumothorax

Improvement of 10% mortality w/Surfactant useage Cystic Fibrosis: TRIAD: Pancreatic Insufficiency, Chromic Pulmonary Disease, Abnormal Sweat Chloride Test (Family Hx 1st cousin) • Multisystem Autosomal Recessive disease • ∆F508 mutation 70% of alleles; genotype is not diagnostic • Defective Cystic Fibrosis transmembrane conductance regulator gene (CFTR) on Chromosome 7 long arm ○ ABC family of Transporters (Cl- channel) • Greatest Prevalence in Caucasians 1/2500 • 2003 Stats Survival for CF patient is >33years of age • Six Classes Of CTFR Mutations VARIABLE DISEASE SEVERITY ○ I – no synthesis ○ II- defective processing ○ III- disordered regulation ○ IV abnormal conduction ○ V reduced Synthesis ○ VI accelerated Turnover Summary: – CTFR activity results from genotype – Individual organ systems require different levels of CTFR activity for normal function – Combination of genotype and organ requirements lead to phenotypic expression – Environmental factors involved in phenotypic expression – Modifier genes also play a role in expression Diagnosis of CF: One of These: Plus one of these: >Typical phenotypic feature of CF Elevated Sweat Cl -on 2 occasions Sybling w/ CF 2 identified CFTR mutations Positive Newborn screening Test Abnormal nasal potential difference Primary Manifestations: 1) Respiratory Tract (Lung) a. Mucus is thicker than normal and serves as breeding ground for INFECTION by bacteria (Staphlococcus/Pseudomonas) Obstruction of airway *IMPORTANT TO TREAT EARLY INFECTIONS* i. Poorly hydrated mucus due to CTFR failure, abn. glycoprotein in mucus, failure of mucocilliary escalator ii.Early Pa infection decreases survival rate iii.Pneumothorax(CP/Tachypnea/Dyspnea/deacreased breathing sounds), iv.Hemoptysis (excessive coughingblood) Older patients v.Respiratory Failure : Hypoexmia(common all stages)/Hypercapnia (END STAGE) vi.Respiratory Disease is the leading cause of death in CF patiens vii.Lung Damage in Early life viii.Early assessment and detection of respiratory disease allow early intervention 2) Digestive Tract (GI): a. Pancreatic Insufficiency, Gastroesophageal reflux , meconium ileus, elevated liver enzymes, CF related Diabetes, Distal intestinal obstructive syndrome( sudden onset of abdominal pain, N/V, constipated), Hepatobilliary disease, Cirrhosis w/ portal hypertension, rectal prolapsed(malabsorption, poor m. tone, large bulky stool), small bowel over growth, Intussusception, fibrosing colonopathy(high pancreatic enzyme, bowel wall thickening, lack of dystensibilty), b. Thick mucus plugs tubes in pancreas to inhibit release of digestive enzymes

c. Autodigestion of pancreasepancreatitisDiabetes d. Affects digestion/absorption of nutrients + Vitamins DEAK i. Conjunctivitis, rickets, ataxia/anemia/hemorrhage ii.PATIENTS ARE UNDERWEIGHT: low weight/age= poor lung function *Vicious Cycle: Mutation CF gene CFTR Abn. Airway SurfaceBronchial Obstruction Infection Inflammation Bronchiectasis(irreversible dilation of bronchial tree/easily collapsible)  RESPIRATORY FAILURE Clinical Case: 1)Failure to thrive infant w. frequent loose fouls smelling greasy stools, large appetite, no weight gain 2) Distended Abdomen in a baby w/mecuonium at birth; Meconium Ileus- dried pebbles of meconium in ileus 3) Chronic Sinusitis, chronic cough, thick green sputum w/blood, “asthmatic” w/no improvement CLUBBING of fingers, nasal polyps, wheezing, Obstructive lung disease, Sweat Cl- is Abnormal Managing Cystic Fibrosis : 1) Early Screening 2) Nutrition – pancreatic enzyme replacement/ vitamins DEAK/ Inceased Calorie intake 3) Infections- Antibiotics (delay onset of Pseudomonas) 4) Inflammation- Antiinflammatory medications 5) Keep BMI >25% 6) Airway Clearance: Levage (improvement in FEV1), postural percussion/drainage; flutter/acapella/ high frequency chest oscillation; EXERCISE 7) Mucolytics a. Dornase Alpha (pulmozyme) b. Hypertonic Saline- restores the airway surface fluidbetter airway clearance 8) Neutrophil death in CF lung Disease; 9) Respiratory Failure BiPAP (positive airway pressure) O2 <92% 10)Lung Transplant