Introduction: Critically ill patients often require emergency endotracheal intubation for airway protection or acute respiratory failure. Ketamine and etomidate are currently recommended by clinical practice guidelines and are among the most common induction agents used for rapid sequence intubation (RSI). The purpose of this study was to compare the hemodynamic effects of ketamine and etomidate in normotensive critically ill patients after RSI.
Methods: This retrospective, multisite cohort study was conducted in normotensive adult hospitalized patients that received ketamine or etomidate for RSI in the emergency department (ED), intensive care unit (ICU), or general hospital floors between January 2020 to October 2024. Patients were excluded if they had hypotension prior to induction or their indication for intubation was cardiac arrest. The primary outcome was rates of post-intubation hypotension. Outcomes were analyzed using a student’s t-test for parametric data or Wilcoxon rank sum test for nonparametric data, and a chi-square test for categorical data.
Results: A total of 211 patients (ketamine n=90, etomidate n=121) met study criteria. Baseline characteristics were well balanced between groups. The most common reasons for intubation were acute respiratory failure (51%) followed by airway protection (36%). Rocuronium was the primary neuromuscular blocker administered after induction (88%) and most patients were intubated in the ED (73%). Rates of post-intubation hypotension were similar between ketamine and etomidate cohorts (24.4% vs 15.7%, p=0.112). There was no difference observed in any of the secondary outcomes such as successful intubation on first-attempt, in-hospital mortality, and rates of cardiac arrest during intubation. The mean duration of mechanical ventilation and vasopressor infusions were the same between both groups. However, there was a statistical significant difference in the rate of vasopressor support initiation post-intubation between ketamine and etomidate (23.3% vs 7.4%, p=0.001).
Conclusions: There was no difference in the incidence of post-intubation hypotension between ketamine and etomidate when used for RSI in normotensive critically ill patients. This study highlights that both of these induction agents for RSI are hemodynamically neutral.
