Abstract Rationale Ketamine and etomidate are medications commonly used to induce anesthesia for emergency tracheal intubation of critically ill adults in many emergency departments (EDs) and intensive care units (ICUs). How the choice between ketamine and etomidate affects patients’ hemodynamics during intubation remains uncertain. Methods The Randomized Trial of Sedative Choice for Intubation (RSI) compared the use of ketamine vs etomidate with regard to in-hospital mortality at 28-days among 2,365 patients from 14 EDs or ICUs. The primary analysis of the RSI trial evaluating the effect of induction medications on mortality included only the initial (index) intubation for each patient. This secondary analysis evaluating the effect of induction medications on hemodynamics during intubation included any intubations for a patient for which the trial determined the induction medication by randomization. The primary outcome was cardiovascular collapse during intubation, defined as a systolic blood pressure 65 mm Hg, new or increased vasopressors, or cardiac arrest between induction of anesthesia and 2 minutes after tracheal intubation. Exploratory outcomes included a systolic blood pressure 90 mm Hg during intubation. Results Among 2,365 patients in the RSI trial, a total of 2,535 intubations occurred, of which 1,268 were randomized to the ketamine group and 1,267 were randomized to the etomidate group. At the time of induction, the median systolic blood pressure was 126 mm Hg (interquartile range, 109-147) in both groups and 22% of patients were receiving vasopressors. Cardiovascular collapse occurred during 283 intubations (22.3%) in the ketamine group and 214 intubations (16.9%) in the etomidate group (absolute risk difference ARD, 5.4 percentage points; 95% confidence interval CI, 2.3 to 8.5). A systolic blood pressure 90 mm Hg occurred during 283 intubations (23.1%) in the ketamine group and 208 intubations (16.8%) in the etomidate group (ARD, 6.3 percentage points; 95% CI, 3.1 to 9.4). Receipt of a new or increased vasopressor occurred during 272 intubations (21.5%) in the ketamine group and 201 intubations (15.9%) in the etomidate group (ARD, 5.6 percentage points; 95% CI, 2.6 to 8.6). The effect of ketamine versus etomidate on blood pressure and receipt of vasopressors during each stage of intubation is shown in Figure 1. Conclusions In this secondary analysis of all intubations in the RSI trial dataset, the use of ketamine to induce anesthesia for tracheal intubation increased the incidences of cardiovascular collapse, hypotension, and vasopressor receipt during intubation, as compared with the use of etomidate. This abstract is funded by: Patient-Centered Outcomes Research Institute
Zehr et al. (Fri,) studied this question.