Etomidate Versus.....

Widely used as an induction agent, etomidate is an ideal agent for emergency endotracheal intubation because:

1. of its predictability in dosing
2. reliable hypnotic effect
3. rapid onset
4. short duration of action
   
5. it has no effect on histamine release, which contributes to its hemodynamic stability.

Unfortunately, since the early 1980s, there has been concerns about the use of etomidate in critically ill sepsis patients because of its adrenal suppression effects resulting in adrenal insufficiency.

Nonetheless, Journal Watch recently publishes a commentary on a study comparing the effects of etomidate versus midazolam. In fact, a further search shows that there has been another comparison study between etomidate versus ketamine. In both of these studies, when put under comparison, etomidate does not demonstrate significant increase in terms of serious adverse effects.

1. Etomidate versus Midazolam

In this prospective, double-blind, randomized trial involving 122 adult patients in a single emergency department with suspected sepsis and indicated for intubation, the patients were randomized to either receivemidazolam (0.1 mg/kg) or etomidate (0.3 mg/kg) for induction.

No significant differences were demonstrated (midazolam vs etomidate) in terms of

• median hospital length of stay (9.5 and 7.3 days)
• median intensive care unit LOS (4.2 and 3.1 days)
• median ventilator days (2.8 and 2.1 days), or
• inhospital mortality (21% and 26%).

A further subgroup analysis of patients who survived to discharge also showed no difference in median hospital LOS between midazolam and etomidate recipients (11.3 and 11.8 days).

Reference:
Tekwani KL et al. A comparison of the effects of etomidate and midazolam on hospital length of stay in patients with suspected sepsis: A prospective, randomized study. Ann Emerg Med 2010 Nov; 56:481. (Abstract)

2. Etomidate versus ketamine

In another prospective trial involving 469 critically ill patients, the patients were randomized to either receive a single intravenous bolus of etomidate (0.3 mg/kg) or ketamine (2.0 mg/kg) for induction. Unlike the other study mentioned, this study involves 65 intensive care units (ICUs) and 12 emergency departments or prehospital systems in France.

And the results are: yes, adrenal insufficiency did indeed occur significantly more among etomidate recipients compared to ketamine recipients (86% vs. 48%; odds ratio, 6.7).

However, in terms of serious adverse events (maximum sequential organ failure assessment (SOFA) scores during the first 3 days in the ICU, or 28-day mortality, etc), again there was no significant differences were noted between groups.

Reference:
Jabre P et al. Etomidate versus ketamine for rapid sequence intubation in acutely ill patients: A multicentre randomised controlled trial. Lancet 2009 Jul 1; click here.

In other words, although etomidate use does show an increase risk of adrenal insufficiency, a single bolus dose of etomidate does not seem to have increased risk of adverse events when compared with other agents. I am awaiting for more studies in this area..........