Ketamine and Etomidate

Ketamine and Etomidate: Good Choices for RSI in Critically Ill Patients
Mortality rates were similar in patients who received single doses of etomidate or ketamine.

Despite etomidate’s hemodynamic benefits, some clinicians have challenged its use for rapid sequence intubation (RSI) in critically ill patients, citing concerns about adrenal insufficiency (JW Emerg Med Feb 1 2008). In a prospective trial, researchers compared outcomes in 469 adult patients who were randomized to receive a single intravenous bolus of etomidate (0.3 mg/kg) or ketamine (2.0 mg/kg) for induction during RSI at 65 intensive care units (ICUs) and 12 emergency departments or prehospital systems in France. All patients received IV succinylcholine (1 mg/kg) immediately after the trial medication and continuous sedation with midazolam (0.1 mg/kg/hour) combined with fentanyl or sufentanil after tube placement was confirmed.

Final diagnoses were categorized as trauma (22%), sepsis (16%), or other (including stroke, overdose, cardiogenic shock, and acute respiratory failure; 62%). Adrenal insufficiency occurred in significantly more etomidate recipients than ketamine recipients (86% vs. 48%; odds ratio, 6.7). However, no significant differences were noted between groups in maximum sequential organ failure assessment (SOFA) scores during the first 3 days in the ICU (the primary outcome), intubation conditions, various measures of catecholamine use, or 28-day mortality. No drug-related adverse outcomes were reported with either agent. The authors conclude that "ketamine is a safe and valuable alternative to etomidate for intubation in critically ill patients, particularly in septic patients." Editorialists suggest that successful intubation depends on a solid knowledge of pharmacology but do not recommend one agent over the other.

Comment: This elegant and ambitious study demonstrated measurable adrenal suppression but no evidence of adverse outcome related to a single bolus of etomidate for RSI in patients with various types of shock. Adrenal axis suppression is common in critically ill patients; in fact, about half the patients who received ketamine had adrenal insufficiency in this study. The authors note that only 16% of study patients had septic shock, and they call for a larger randomized study that includes more patients with sepsis. Clinicians should choose induction drugs based on individual patient parameters and personal familiarity and not be dissuaded from using either etomidate or ketamine based on concerns that are not supported by evidence.

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Kristi L. Koenig, MD, FACEP
Published in Journal Watch Emergency Medicine July 2, 2009

Citation(s): Jabre P et al. Etomidate versus ketamine for rapid sequence intubation in acutely ill patients: A multicentre randomised controlled trial. Lancet 2009 Jul 1; [e-pub ahead of print]. (http://dx.doi.org/10.1016/S0140-6736(09)60949-1)

Wenzel V and Lindner KH. Best pharmacological practice in prehospital intubation. Lancet 2009 Jul 1; [e-pub ahead of print]. (http://dx.doi.org/10.1016/S0140-6736(09)61071-0)