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.
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:
Determine that the gas exchange is adequate:
Determine that the chest wall mechanics are adequate:
Assess airway protective reflexes
Assess airway patency
Consider postponing extubation.
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:
AARC GUIDELINE: REMOVAL OF THE ENDOTRACHEAL TUBE; RESPIRATORY CARE •JANUARY 2007 VOL 52 NO 1
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.