Tuesday, 23 April 2019

Bag-Mask Ventilation during Tracheal Intubation of Critically Ill Adults: A tack in the coffin of RSI


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“Rapid sequence induction” is intended to decrease pulmonary aspiration during endotracheal intubation. Classily it requires a period of apnoea during which time we wait for the paralytic agent to take effect. No breaths are given for fear of insufflating the stomach and increasing the risk of aspiration.

But what if this period of apnoea is worse that the theoretical risk of aspiration? Herein lies a decent research question.

But spoiler… this was not fully addressed with this study.

This RCT in 7 ICU’s in the USA randomised 401 adult patients to BVM or no ventilation between induction and laryngoscopy. They excluded patients at high risk for aspiration (i.e. ongoing emesis, bowel obstruction, haematemesis etc.)

The primary outcome was lowest oxygen saturation. They also looked at many secondary outcomes and rates of pulmonary aspiration.

Results?

Those that got BVM had lower rates of hypoxemia. Rates of severe hypoxemia (sats less than 80%) were 11% in the BVM group but 23% in the no-ventilation group. This is hardly surprising but ultimately is not a patient-oriented outcome.

As expected, the incidence of pulmonary aspiration was quite low. It was noted in 5 (2.5%) patients in the BVM group vs. 8 (4%) in the apnoea group. With such small numbers, obviously this is not statistically significant.

The authors state the following:

Given the low incidence of operator-reported aspiration during tracheal intubation of critically ill adults, determining whether bag-mask ventilation increases the relative risk of aspiration by 50% would require a trial enrolling approximately 4000 patients.

Yikes! 

I don’t think we’ll see this trial anytime soon.

There were a number of limitations in this trial. It was performed only in ICU’s, high risk patients were excluded, no blinding, the gold standard for aspiration is problematic, etc.

Do we have an answer? Is RSI dead?

Not really. But perhaps this is a tack (but not a nail) in the coffin of RSI.

Ultimately, I think we can use our common sense and cater to the individual patient. Those that are hypoxic are probably fine to have some BVM. Hold off on those where oxygenation is ok and/or high risk for aspiration.


Covering:

Casey JD, Janz DR, Russell DW, et al. Bag-Mask Ventilation during Tracheal Intubation of Critically Ill Adults. N Engl J Med 2019;380:811-21. [link to article]



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