When is a patient ready to be extubated? They should fulfill at least the following criteria:

  • PaO2/FiO2 > 150
  • PEEP ≤ 8 cmH2O
  • Minimal need for inotropes and sedation
  • Intact airway reflexes (e.g. adequate cough while suctioning)
  • F/Vt (respiratory rate per minute ÷ tidal volume in litres) ≤ 105
  • Awake, breathing spontaneously and able to protect airway
  • Passed trial of spontaneous breathing (e.g. can tolerate CPAP with PS of 5 cmH2O)

Trial of spontaneous breathing

While on the ventilator, a patient can be switched to CPAP (continuous positive airway pressure) with PS (pressure support) of 5 cmH20 for 30 minutes to 2 hours. In this mode, the ventilator stops breathing for the patient and the patient has to initiate his or her own breaths. Patients who pass this trial are better candidates for extubation. Patients fail the trial if they show signs of distress:

  • SpO2/SaO2 < 90%
  • Heart rate > 140 BPM or change by ≥ 20%
  • Systolic BP > 180 mmHg or < 90 mmHg
  • Sustained RR > 35 per minute (for over 5 minutes)
  • Increased anxiety or diaphoresis