Ketamine and etomidate use for RSI in trauma have similar effect on first-pass success rate

30th May 2023

Although ketamine use increases haemodynamic instability during rapid sequence intubation in trauma patients, it does not significantly affect the first-pass success rate compared to etomidate, according to a retrospective analysis.

Published in the journal BMC Emergency Medicine, Korean researchers considered whether the potential adverse effects of ketamine and etomidate could affect the first-pass success rate during rapid sequence intubation (RSI) in trauma patients.

The team retrospectively compared both sedatives, not only in terms of the effect on the first-pass success rate but also with respect to clinical outcomes. Patients given ketamine were propensity-matched 1:3 with etomidate and the results adjusted for injury severity and confounding baseline characteristics.

Understanding RSI

RSI represents the set of actions undertaken during induction of anaesthesia that secures the airway in trauma patients at risk of aspiration or regurgitation of gastric contents, to enable emergency orotracheal intubation. Ideally, the RSI procedure should allow for rapid and optimal intubation conditions through increasing the first-pass intubation rate whilst reducing adverse events in severely injured patients. Despite being a standard procedure, a recent survey identified significant variation in practice, prompting called for international RSI guidelines.

Both ketamine and etomidate are commonly used sedatives for RSI during emergency tracheal intubation. Nevertheless, both are associated with potential adverse effects which could affect clinical outcomes. For example, single dose use of etomidate may increase 28-day mortality, whereas ketamine use could increase the risk of cardiac arrest.

No impact on clinical outcomes

A total of 620 patients, of whom 19.9% received ketamine, were included in the retrospective analysis. The ketamine patients had a significantly faster initial heart rate (105.0 vs 97.7, p = 0.003) and were more hypotensive (114.2 vs 139.3 mmHg, p < 0.001) than those given etomidate.

However, when researchers considered the first-pass success rate, this was not significantly different (90.7% vs. 90.1%, ketamine vs etomidate, p > 0.999). Similarly, there were no differences in other clinical outcomes explored including final mortality (p = 0.348), length of intensive care unit stay (p = 0.99), ventilator days (p = 0.735) and overall hospital stay (p = 0.32).

The authors concluded that when used for RSI, although patients administered ketamine showed greater haemodynamic instability, this had no important impact on either the first-pass success rate or other relevant clinical outcomes.