Q: All of the following are risk factors for re-intubation except?

A) weak cough strength
B) requiring frequent suctioning
C) a rapid shallow breathing index (RSBI) more than 58 breaths/min per L, 
D) a negative fluid balance during the 24 hours preceding extubation, 
E) Intubation secondary to pneumonia 


Answer: D

Below 15 percent of failed planned extubations is a acceptable number for any ICU. There are many factors which may lead to failure of planned extubation including choice A, B and C.

Choice C is interesting as conventional teaching is RSBI less than 100 breaths/min per L is acceptable. It is true in most situations but risk of extubation failure start to rise once it goes above 58 breaths/min per L 2. It is actually a positive fluid balance particularly in preceding 24 hours which may be a problem. Also, patient's baseline cardiopulmonary health plays an important role in success of extubation.



References: 

1.  Frutos-Vivar F, Ferguson ND, Esteban A, et al. Risk factors for extubation failure in patients following a successful spontaneous breathing trial. Chest 2006; 130:1664. 

2. Thille AW, Harrois A, Schortgen F, et al. Outcomes of extubation failure in medical intensive care unit patients. Crit Care Med 2011; 39:2612.

3. Esteban A, Anzueto A, Frutos F, et al. Characteristics and outcomes in adult patients receiving mechanical ventilation: a 28-day international study. JAMA 2002; 287:345.