Extubation criteria after general anaesthesia

Awake extubation: the usual checklist

• Neuromuscular blockade must be fully reversed. Quantitative monitoring should show a train-of-four (TOF) ratio of at least 0.9 before extubation, and this should be documented in the anaesthetic record (Barash, Clinical Anesthesia 9e).
• Clinical signs of adequate strength are sustained tetanus on the nerve stimulator and a 5-second head lift, in an awake patient who follows commands (Miller's Anesthesia 10e, Airway Management).

• The patient opens their eyes and follows commands.
• Cough and gag reflexes have returned, and the patient is not in stage 2 (the excitatory phase of emergence). Extubation in stage 2 risks breath-holding, laryngospasm, upper airway obstruction and aspiration (Barash 9e, Tracheal Extubation, p. 3769).
• End-tidal volatile concentration is low, around 0.2 MAC or less. Residual anaesthetic can delay awakening (Morgan & Mikhail 7e).

• Regular spontaneous breathing at a rate of about 10 to 25 per minute.
• Tidal volume above 5 mL/kg, and vital capacity above 10 to 15 mL/kg.
• SpO2 of 95% or more on FiO2 of 0.4 or less. PaO2 above 60 mmHg and PaCO2 below 50 mmHg if checked.
• Negative inspiratory force more negative than -20 to -25 cmH2O.
• Good end-tidal CO2 trace.

• Haemodynamically stable, with no significant arrhythmia, bleeding or ongoing resuscitation.
• Temperature of at least 36 °C, no major acid-base or electrolyte disturbance, and adequate analgesia.
• No anticipated airway oedema or obstruction. If there is doubt, check for a cuff leak.

• Suction the oropharynx under direct vision.
• Preoxygenate with 100% O2.
• Extubate at end-inspiration with positive pressure (Barash 9e, Perioperative Aspiration).
• Have airway adjuncts and a reintubation plan ready.

Paediatric criteria

1. Conjugate gaze
2. Facial grimace
3. Eye opening
4. Purposeful movement
5. Tidal volume above 5 mL/kg

• A URI within the previous 7 days.
• Midazolam premedication in children over 1 year.
• ETCO2 above 55 mmHg.

Deep extubation

• Requirements: adequate spontaneous ventilation on minimal settings, no response to suction or jaw thrust, and PACU staff able to manage the airway.
• Contraindications:
  • Aspiration risk or a full stomach
  • Difficult airway
  • Obstructive sleep apnoea (OSA)
  • Copious secretions or bleeding
  • Significant airway obstruction at induction

Situations where extubation should be delayed

• Trauma or major surgery: continue ventilation if there is CNS injury, chest wall or pulmonary injury, massive transfusion, airway oedema or ongoing intoxication. Miller's Box 62.11 lists criteria for extubation after emergency trauma surgery. About 12 to 24 hours of support allows resuscitation to be confirmed (Miller's Anesthesia 10e, Emergence and Tracheal Extubation).
• Obese or OSA patients: extubate fully awake, head-up, with CPAP ready (Miller's Anesthesia 10e).
• Difficult airway or aspiration risk: extubate in the operating theatre with rescue equipment available. Consider an airway exchange catheter.

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