Ch 62 Dos And Don'ts

CHAPTER 62

DOs AND DON’Ts AND SOME COMMON PROBLEMS

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DOs AND DON’Ts DO •

See every patient before surgery if possible. Plan a suitable anaesthetic and decide on whether premedication requires to be ordered.

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Inform the surgeon both before and during the surgery if you are concerned about the patient's general condition.

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Whenever you have a poor risk patient, always have a large bore cannula in place and a good intravenous infusion running.

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Have a pumping device available for intravenous fluids if you expect major blood loss.

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Remember that large volumes of blood are lost into the sites of fractures.

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Monitor anaesthetised patients meticulously and chart the readings immediately.

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Choose a regional anaesthetic technique wherever possible in preference to general anaesthesia, provided there is no contraindication to a regional technique and it is appropriate for the surgery which is to be performed.

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Check the anaesthetic machine before every anaesthetic.

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Pre-oxygenate (before induction) every poor risk patient, every potentially difficult intubation and every patient for a rapid sequence induction.

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With poor risk patients, reduce the prescribed dose of anaesthetic drugs and increase the inspired oxygen concentration.

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Remember: elderly patients have a very prolonged circulation time. You need to wait much longer before the drugs administered take effect.

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Have an assistant to help monitor and/or ventilate the patient,

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especially if you don’t have a mechanical ventilator.

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In thyroidectomy patients, watch for respiratory difficulties following extubation. Always be ready to re-intubate if necessary.

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Note when pharyngeal packs are inserted and when they are removed.

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Observe aseptic (sterile) technique for spinals and for insertion of intravenous cannulae.

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Before a spinal anaesthetic, check the patient's blood pressure and insert an intra-venous cannula.

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If patients have had anaesthetic complications, make sure you see them after surgery. Try to see all patients post-operatively - even routine cases.

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Take time to prepare everything that may be necessary before commencing.

DON’T •

Don't give a general or a regional anaesthetic (e.g. spinal) unless oxygen, a means of ventilation, suction and resuscitation drugs are available in the operating theatre.

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Don't premedicate the following patients with narcotic analgesics − Moribund patients − Babies less than 6 months old − Patients for caesarean section or forceps delivery − Patients with head injuries, with a raised intracranial pressure

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Don't concentrate on the surgical procedure and neglect to monitor the patient.

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Don't anaesthetise a patient with a pre-existing medical problem unless an attempt has been made to correct it. This applies especially to elective surgery.

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Don't leave an unconscious patient for any reason at all unless you have asked someone responsible to watch the patient for you.

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Don't hesitate to intubate a patient if a clear airway cannot be maintained with other means (e.g. re–positioning of head or jaw, the

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use of a Guedel airway or LMA).

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Don't let a pregnant mother at term lie on her back (supine).

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Don't give a hypotensive mother at term either a general or a spinal anaesthetic until the cause is diagnosed and treated. Uncontrolled bleeding is an exception where general anaesthesia with aggressive fluid resuscitation occurs concurrently with surgery to correct the problem.

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Don't hesitate to refuse to anaesthetise a patient if you feel you haven't had enough experience.

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Don't hesitate to ask for help if you need it, even if it means the surgeon has to get unscrubbed.

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Don't let any one force you to do something which in your view is not safe.

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Don't let experience in the field of anaesthetics make you feel you can bypass the safety measures you have learned.

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Don't use relaxants and paralyse patients unless you are sure of intubating them or ventilating them with a mask. Don't paralyse patients with an obstructed airway, or those with anatomical or pathological problems that will make intubation difficult.

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Don't use suxamethonium any later than 48 hours after moderate to major burn injuries.

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Don't use force when intubating a patient. Don't use a big tube, especially in children. Don't over-inflate the cuff.

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Don't discharge a child who has had an endotracheal intubation until at least 6 hours after extubation.

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Don't extubate a patient until you are sure that reversal is complete.

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Don't anaesthetise a child without first working out the doses of drugs and the volumes of maintenance fluid that you will need and preferably checking with another anaesthetist.

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Don't use adrenaline for local anaesthetic blocks on the fingers, toes or penis.

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COMMON PROBLEMS AND HOW TO MANAGE THEM DIFFICULTY IN CANNULATING A VEIN • • • • •

Proceed with an inhalational induction using ether or halothane if there is no risk of aspiration and you are confident that the airway will be easy to manage. The resulting vasodilation may help you cannulate. Induce anaesthesia with IM Ketamine. Allow the patient to breath oxygen and halothane or ether. Proceed with cannulation. Cut down on to a vein. Cannulate a central vein. Consider intraosseous access in a child.

ACCIDENTAL INTRA-ARTERIAL INJECTION OF THIOPENTONE (see Chapter 6 Pharmacology) • • • • • • • •

Postpone surgery if possible. Leave the needle in the artery. Flush with anticoagulant e.g. heparin/saline (10 units/ml) 500 units Inject procaine 0.5-1% 10-20ml or lignocaine 1% 5-10 ml or papaverine 10-40mg in 10ml of normal saline intra-arterially. Heparin 10,000 units may be given intra-arterially. The patient may be allowed to breathe oxygen/ether or oxygen/halothane in order to vasodilate the collateral circulation. Elevate the arm. Surgery to restore the blood supply through the artery may be required.

Other measures − A supraclavicular brachial plexus block or a stellate ganglion block may increase the collateral circulation to the limb. This must be done by someone with the necessary expertise, before the heparin is administered. − Support the patient's circulation and respiration. WHEN THE AIRWAY IS OBSTRUCTED by the tongue falling back • • • •

Extend the head Lift the chin and perform jaw thrust Insert a Guedel airway. If there is no relief try inserting a LMA. If there is still no relief perform endotracheal intubation.

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WHEN THE AIRWAY IS OBSTRUCTED by jaw muscle spasm and the tongue falling back • • •

Use a mouth gag to force open the jaws Insert a Guedel airway and continue the anaesthetic Consider deepening anaesthesia

LARYNGEAL SPASM • • • •

Stop surgical stimulation Give the patient 100% oxygen to breathe via the mask Deepen the general anaesthesia If there is no relief, give suxamethonium 0.1-0.2mg/kg IV. This will correct the problem if it is true laryngospasm. Continue to ventilate with 100% oxygen. • Endotracheal intubation if the airway is still not secured (give suxamethonium 1mg/kg). The spasm may recur on extubation. BRONCHOSPASM • • • •

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Increase inspired oxygen concentration. Deepen the general anaesthesia using halothane or ether. Salbutamol, either via a nebuliser through an adapter in the circuit or 0.25mg IV over 1 minute (=250 micrograms). If salbutamol is unsuccessful give adrenaline 50–100 micrograms IV (0.5 – 1 ml of 1:10,000 or 0.05 – 0.1 ml of 1:1000) or adrenaline 0.5-1mg IM (0.5 – 1ml of 1:1000) titrated to effect. Give hydrocortisone 100mg IV (this will take a number of hours to work). Aminophylline 250mg slowly IV.

THE PATIENT FAILS TO RELAX The cause must be found. Don't attempt intubation until the patient is relaxed. Possible causes: • The tourniquet is still on. • The needle or cannula is in the tissues. • The dose of relaxant was inadequate. • The drug was defective. • Less common causes: − An early sign of malignant hyperpyrexia.

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Contractures, not relaxed by muscle relaxant. Underlying myotonia dystrophica.

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ANTICIPATED DIFFICULT INTUBATION (See also Chapter 21) •

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If you suspect anatomical reasons, e.g. bull neck or receding chin: − Pre–oxygenate for 3-4 minutes. − Make sure an introducer, bougie and a laryngeal mask are available. − Position the patient carefully (sniffing position). − Use suxamethonium rather than a long-acting relaxant, (inhalational induction in children). − Apply external backwards pressure on the larynx. If you suspect pathological reasons, e.g. tumour of the neck, jaw, face, contractures, tumours or inflammation of the pharynx or mouth: − Don't paralyse the patient unless you can guarantee ventilation. − Use an inhalational induction. − Occasionally you may need an awake intubation or tracheostomy before the anaesthetic is induced.

FAILED INTUBATION (See also Chapter 21 pages 322-323) Hypoxia must be avoided at all costs. In patients with a full stomach aspiration of gastric contents is very likely. • Call for help and failed intubation equipment. • Mask ventilate with 100% oxygen. Continue applying cricoid pressure if there is a risk of aspiration. Assess adequacy of ventilation and oxygenation. • Decide whether it is essential to proceed with surgery or not. If not, wake the patient up and postpone the procedure. In elective surgery − Plan an alternative method using a regional technique or awake intubation. In emergency surgery (e.g. caesarean section for foetal distress) − Continue with mask ventilation and cricoid pressure. Consider the use of a laryngeal mask airway with cricoid pressure. − Allow the short acting muscle relaxant to wear off and get the patient breathing with either a face mask +/- Guedel airway or laryngeal mask. − If a long-acting muscle relaxant has been administered, optimise attempts at intubation by improved positioning and by using

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intubation aids e.g. stylet or bougie, other laryngoscope blades and call for a more experienced anaesthetist.

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YOU CAN'T VENTILATE OR INTUBATE THE PATIENT If all the above methods have failed • Cricothyroid puncture with a 12 or 14 gauge IV cannula. (See page 324 Chapter 21). Note: the 12G or 14G cannula is inserted into the trachea through the cricothyroid membrane. Confirm correct placement by air aspiration through the cannula using a syringe. Connect a 2 ml syringe to the cannula. Insert a 7.5mm ETT connector into the syringe barrel. This will then provide the 15/22 mm connection for a self-inflating bag or the anaesthetic breathing circuit. It is difficult to give big tidal volumes but use 100% oxygen and you will keep the patient alive. • Tracheostomy. INCREASING DIFFICULTY IN VENTILATING AN ANAESTHETISED PATIENT Possible causes: • Airway obstruction − The patient's upper airway (including laryngeal spasm) − The endotracheal tube blocked or kinking − The machine • Bronchospasm • Returning muscle tone in the chest wall and diaphragm • Pneumothorax • Abdominal distension interfering with ventilation Management • Take the patient off the ventilator. Ventilate manually. • Suction the ETT. • Increase the oxygen concentration. • Treat the cause. TEARS Inadequate depth of anaesthesia. RASHES • •

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Drug reaction. Avoid any further doses. If associated with hypotension and bronchospasm, a rash may indicate a transfusion reaction or anaphylaxis - see below.

SWEATING Possible causes • Light anaesthesia • Carbon dioxide retention, because of: − Hypoventilation − Respiratory obstruction − The carbon dioxide absorber is not working − Increased dead space • Hypoxia • Increased temperature • Shock • Hypoglycaemia • Malignant hyperpyrexia. HICCUPS • • •

Deepen anaesthesia Stop surgical stimulation in the region of the diaphragm Give an additional dose of muscle relaxant.

ANAPHYLACTIC REACTION TO DRUGS • • • •

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Stop administration of suspected drug or drugs IV infusion of crystalloid and colloid solution Give 100% oxygen by mask or endotracheal tube Adrenaline IV 0.1-0.5ml of 1:1000 or 1-5ml of 1:10,000 solution. Repeat as necessary. NB. Increase dose of adrenaline up to 1mg if intractable hypotension develops. Commence adrenaline infusion. Hydrocortisone 200mg IV Salbutamol 250 micrograms IV (second line for bronchospasm) Aminophylline 250mg IV for bronchospasm (third line for bronchospasm) Antihistamines such as promethazine (Phenergan) 25mg slowly IV or chlorphenamine maleate (Piriton) 10mg IV. Check arterial blood gases and consider Na bicarbonate if pH < 7.1.

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CENTRAL CYANOSIS Management: • Turn off all anaesthetics. • Ventilate with 100% oxygen. • Monitor pulse and blood pressure. • Watch for cardiac arrest. Treat the cause. Always ventilate the cyanosed patient by hand. Some causes of cyanosis: • Inadequate oxygen supply − Empty cylinders − Defective flow meters − Disconnection of apparatus − Doubtful quality of oxygen − A malfunctioning ventilator • Respiratory obstruction: − Upper airway − The endotracheal tube − Bronchospasm. • Pneumothorax. • Hypoventilation of lungs, for example pulmonary oedema, pneumonia, collapse. • Inadequate blood flow to the lungs due to: − Hypotension. − Cardiac failure. − Pulmonary embolism. • Other causes of cyanosis − Air embolism − Malignant hyperpyrexia − Anaphylaxis. PULMONARY OEDEMA • • • • •

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Stop the fluid load. Give oxygen and IPPV (IPPV if severe and unresponsive to therapy). Give diuretics - frusemide 20- 40mg IV. Give Digoxin (only for rapid atrial fibrillation). Prop up the patient.

TRANSFUSION REACTION • • •

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Stop blood transfusion Give fluids - Hartmann’s solution or colloids to maintain urine output Give adrenaline if hypotension develops which would indicate a severe reaction. Start at low doses such as 50-100 micrograms, repeated as necessary. High doses (i.e. 1mg) such as for cardiac arrest may be required if cardiovascular collapse occurs. Clinically this can be similar to anaphylaxis. Give oxygen: intubate and ventilate if severe reaction. Give Mannitol 25G IV or Lasix 40mg IV. Give steroids: Hydrocortisone 100mg IV. Dialysis may be required if acute renal failure develops. (Send the remaining donor blood, a fresh sample of the patient's blood and urine to the laboratory).

INCREASED BLEEDING FROM A WOUND • •

Surgical bleeding from an artery or vein must be treated by the surgeon. Capillary bleeding. Check the following possible causes: − Carbon dioxide retention − Oxygen lack − Increased venous pressure, (in head and neck surgery this may be caused by coughing or straining) − Bleeding problems • Lack of platelets • Lack of clotting factors • Lack of calcium • D.I.C. • Continued use of aspirin − Mismatched transfusion.

SEVERE HYPOTENSION • • • •

Treat any underlying cause, e.g. blood loss, fluid loss, arrhythmias, myocardial infarction, pressure from retractors, traction on the gut, anaphylaxis, tension pneumothorax, anaesthetic drugs. Turn off anaesthetic agents and ventilate with 100% oxygen. Give IV fluids rapidly. If necessary insert a second cannula. Watch for cardiac arrest. Investigate and treat the cause. e.g. hypoxia. If there is no response, try vasopressors such as − Metaraminol (Aramine) 1 mg IV p.r.n.

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Adrenaline 0.1-1mg IV, titrate to response. If diagnosed cardiac arrest, give 1mg of adrenaline and proceed with CPR.

CARDIAC ARREST (See Chapter 58) • •

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Airway Breathing

– Clear – Give mouth to mouth ventilation – Ventilate with a bag, valve and mask – Insert LMA or – Endotracheal intubation Cardiac massage Drugs and drip – Adrenaline 1mg. ECG – Ventricular fibrillation : Defibrillate − Ventricular tachycardia : Lignocaine 1% 1mg/kg IV or amiodarone 300mg IV (if available) − Asystole : Adrenaline 10ml of 1:10,000, or 1ml of 1:1000 Find and treat the cause.

AIR EMBOLISM • • • • •

Place the patient in the head down, left lateral position. Give oxygen (100%) via mask or endotracheal tube. Treat arrhythmias and hypotension. Prevent further emboli by flooding the wound with saline and jugular compression. Aspirate air via a catheter in the right atrium or ventricle.

MALIGNANT HYPERPYREXIA (See Chapter 46) • • • • • • • • • •

Stop volatiles and keep the patient sedated with IV benzodiazepines e.g. diazepam or midazolam. Ventilate with 100% oxygen. If it is available give dantrolene 1mg/kg IV, with further doses of 1mg/kg up to a maximum of 10mg/kg. (This is a very expensive drug). Give IV fluids, i.e. a rapid infusion of crystalloid. Cool the patient with ice, fans, wet sheets, ice-cold fluids (saline) and an ice-cold saline gastric lavage. Cease when temperature has come down to 38oC. Continuously monitor core temperature. Monitor temperature, urinary output, pulse, blood pressure and if possible arterial blood gases, electrolytes. Give sodium bicarbonate 50mmol IV, initially. Maintain urine output of 2ml/kg/hr Lasix 40mg IV and Mannitol 12.5g IV may be required. Glucose/insulin infusion if the potassium (K+) level is high. Treat any arrhythmias which develop.

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Investigate the patient and the patient's family further.

RESIDUAL NEUROMUSCULAR BLOCK •

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Treat the cause if possible. Some causes are: − Inadequate dose of neostigmine. − Electrolyte imbalance and metabolic acidosis. − Hypothermia. − The use of certain antibiotics e.g. gentamicin. − Magnesium sulphate. − Underlying medical problems, e.g. a very ill patient, myasthenia gravis, myasthenic syndrome. Don't extubate the patient. Continue the anaesthetic until spontaneous respiration returns.

POST-OPERATIVE APNOEA

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Leave the endotracheal tube in place. Ventilate the patient with oxygen (and nitrous oxide if available). Treat the cause, which could be: Overdose of drugs: − Premedication drugs − Induction agents − Maintenance drugs − Analgesics. Hypocarbia Abnormal blood glucose Hypoxia Residual neuro-muscular block − Depolarising relaxant • Low or abnormal pseudocholinesterase • Dual block − Non-depolarising relaxant • Inadequate neostigmine • Electrolyte imbalance • Metabolic acidosis • Myasthenia gravis or myasthenic syndrome • Very ill patient Hypercarbia Hypothyroidism.

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DELAYED RETURN OF CONSCIOUSNESS •

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Maintain ventilation − Oxygen − The airway must be clear • Lift chin and jaw • Insert Guedel airway • Insert LMA or endotracheal tube if required − IPPV may be required. Maintain circulation − Monitor pulse and blood pressure − Give IV fluids Never leave the unconscious patient unattended. Treat the cause. Some causes are: Respiratory problems − Hypoventilation − Airway obstruction − Pneumothorax − Lung disease: collapse, pneumonia − Decreased blood flow through lungs: • Cardiac failure • Pulmonary embolism − Carbon dioxide absorber not working Central depression (drug action) − Premedication − Induction agents − Maintenance agents, e.g. ether or halothane − Analgesic drugs. Underlying medical problems − CVA − Hyperglycaemia − Hypoglycaemia − Sickle cell disease − Fat embolism − Monoamine oxidase inhibitor drugs − Porphyria.

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ABNORMAL MUSCULAR MOVEMENTS AFTER ANAESTHESIA Find the cause: • Inadequate reversal of muscle relaxant • Shivering • Ketamine hallucinations • Convulsions: − Find the cause: hypoxia, hypoglycaemia, low calcium level, withdrawal of anticonvulsants before surgery, pyrexia, central nervous system disease (e.g. cerebral oedema), water intoxication, eclampsia. − Maintain a clear airway and give oxygen − Give anticonvulsants Diazepam: 100 micrograms/kg IV until the convulsion stops, or Thiopentone: 50-100mg IV. − Give suxamethonium 1mg/kg IV and ventilate with 100% oxygen. − Intubate if necessary. ASPIRATION DURING ANAESTHESIA • • • •

Position the patient in the head down lateral position if airway unprotected. Suction Give oxygen Auscultate the chest for signs of aspiration. If significant aspiration with persistent hypoxia then intubate the patient in the supine position with cricoid pressure. then − Suction via endotracheal tube − Antibiotics (if the gastric aspirate is thought to be infective, i.e. bowel obstruction) − Bronchodilators, e.g. salbutamol 250 micrograms slowly IV, adrenaline 50-100 micrograms IV, aminophylline 250mg IV. − IPPV − Bronchoscopy.

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POST–OPERATIVE LARYNGEAL OEDEMA This is more common in children (See Chapter 20). • Humidified oxygen • Give adrenaline nebules, 1mg (with 1ml of normal saline) up to 5mgs until relief is achieved. • Give steroids (dexamethasone up to 8mg IV or hydrocortisone up to 100mg IV). • Perform an endotracheal intubation using a very small tube, or tracheostomy if the situation deteriorates in spite of above measures. WHAT TO DO IF THE LARGE OXYGEN CYLINDER RUNS OUT DURING A GENERAL ANAESTHETIC This should not happen. Check the cylinder and check with the surgeon the expected duration of surgery. A rough guide: 500 ml of oxygen in a large cylinder lasts for 1 hour at most. If you do have to change a cylinder • If the patient is breathing spontaneously (with a face mask or laryngeal mask) − Disconnect the machine − Give IV ketamine 0.5 - 1 mg/kg and breathe air or − Connect to EMO - breathe ether starting with 3%. Gradually increase the concentration. • If you are controlling respiration − Use a self inflating bag to ventilate the patient − Give IV ketamine 0.5 - 1 mg/kg.

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