Question 26

A 68-year-old male remains intubated four days after an out of hospital cardiac arrest. He is agitated on low dose propofol and only intermittently follows commands. His ventilation is pressure support (PSV) with FiO2 0.45, PS 10 cmH2O and PEEP 8 cmH2O. He is generating tidal volumes of 460 mls with a respiratory rate of 22 breaths/min and oxygen saturations of 94%.

Outline how you would determine his readiness for extubation.

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College answer

Not available.


This patient is at risk of extubation failure. Firstly, some might say that an FiO2 45% is still too high to consider extubation, and others might point to the relatively brisk four day course since his cardiac arrest. This question is functionally indistinguishable from Question 11  from the second paper of 2011, which asked you to extubate a "45-year-old intellectually handicapped man". The basic issue is the same: this patient's neurology is difficult, and you have to adjust your expectations. And, as in all such cases, to a considerable extent his readiness for extubation would be related to your readiness to reintubate him. 

First: assure yourself that the basic preconditions are met:

  • The resolution of the condition which had required the intubation and ventilation (hypoxic brain injury) is still in progress. 
  • Haemodynamic stability, specifically his cardiac function needs to be satisfactory to endure the increased demand from hard-working respiratory muscles
  • Adequate muscle strength (this might be challenging in an uncooperative patient, but he at least intermittently obeys commands)

Determine that the gas exchange is adequate:

  • Decrease the FiO2 to 40% or lower
  • Observe the SpO2 and respiratory rate to assure yourself that a high FiO2 is not required

Determine that the chest wall mechanics are adequate:

  • This patient recently had CPR. Assure yourself that he does not have a flail segment of clinically significant chest wall injuries.

Assess airway protective reflexes

  • Good cough reflex on tracheal suctioning
  • Good gag reflex on oropharyngeal suctioning

Assess airway patency

  • Perform a cuff leak test
  • Ideally, perform it under direct laryngoscopy vision, assuring yourself that a) there is definitely space in the airway, and b) that you can perform direct laryngoscopy on this patient if push comes to shove

Reassess neurology

  • Cease the propofol entirely and transition the patient to another agent, eg. dexmedetomidine
  • Cease any other agents which might depress the level of consciousness
  • Reassess neurology and readjust your expectations
  • Realistically, this patient may remain confused for some days to come, and he does not need to spend all of those days intubated

Consider postponing extubation. 

  • Extubation is an entirely elective procedure.
  • A delay may improve the degree of airway oedema, or allow for expert staff to assemble so that the best chance of reintubation is afforded.


On page 362, Bersen references this Chest article from 2001, where the evidence for extubation criteria is summarised.
MacIntyre NR (chairman), Evidence-based guidelines for weaning and discontinuing ventilatory support: a collective task force facilitated by the American College of Chest Physicians; the American Association for Respiratory Care; and the American College of Critical Care Medicine. CHEST December 2001 vol. 120 no. 6 suppl 375S-396S.

Recommendations regarding which conditions favour extubation has been put forward in a 2007 practice guidelines statement by the AARC:

Karmarkar, Swati, and Seema Varshney. "Tracheal extubation." Continuing Education in Anaesthesia, Critical Care & Pain 8.6 (2008): 214-220.

Mitchell, V., et al. "Difficult Airway Society Guidelines for the management of tracheal extubation." Anaesthesia 67.3 (2012): 318-340.

Kriner, Eric J., Shirin Shafazand, and Gene L. Colice. "The endotracheal tube cuff-leak test as a predictor for postextubation stridor." Respiratory care 50.12 (2005): 1632-1638.