Authors: Upchurch CP et al., Ann Emerg Med 2017 Jan 69:24
An observational study suggests that these two agents are similarly safe but sends a possibly worrisome signal.
Several studies have sought — and failed to find — evidence that etomidate is bad for patients due to the adrenal suppression it is known to cause (NEJM JW Emerg Med Mar 2014 and Anesth Analg 2013; 117:1329). Meanwhile, ketamine has emerged as an attractive alternative (NEJM JW Emerg Med Feb 2013 and J Trauma Acute Care Surg 2012; 73:1401). These investigators evaluated patient outcomes at one academic Level I trauma center before and after an institutional switch from etomidate to ketamine as the principal agent for rapid sequence intubation.
They compared 526 patients who received etomidate before the protocol change with 442 who received ketamine after the protocol change. In-hospital mortality (the main outcome), and the number of intensive care unit–free days and ventilator-free days did not differ in the two groups. Ketamine was associated with lower odds of hospital-acquired sepsis (odds ratio, 0.72) but fewer vasopressor-free days (OR, 0.74).
Unfortunately, the finding that hospital-acquired sepsis was more common in the etomidate group provides ammunition for etomidate critics. This drawback is balanced by the finding of fewer days on vasopressors with etomidate. A prior randomized trial provided higher quality evidence than this nonrandomized observational study with historical controls can and suggested that the two agents are equivalent (NEJM JW Emerg Med Aug 2009 and Lancet 2009; 374:293). Our current understanding of these agents should not cause us to favor one over the other and current practice should not change — both agents are ideal because they cause minimal hypotension at the time of intubation.