Peri-intubation hypotension (PIH) is associated with increased mortality. Etomidate and ketamine are commonly used as induction agents for tracheal intubation in the emergency department (ED) due to their favorable hemodynamic profiles. However, the effects of these agents on PIH remain controversial, and data on elderly patients are limited. This study aimed to compare the effects of etomidate and ketamine on PIH and 28-day mortality.

A prospective, observational, propensity-matched cohort study was performed across two ED centers between March 23, 2022, and September 30, 2023. Patients aged 65 years and older requiring tracheal intubation and receiving either etomidate or ketamine as a single induction agent were included. The primary outcome was the incidence of PIH within 30 min post-induction, comparing etomidate and ketamine. PIH was defined as a systolic blood pressure (SBP) decrease of more than 20 % from baseline, SBP <100 mmHg (with or without fluid resuscitation), or the initiation or increased dose of vasopressor therapy. Secondary outcomes included 28-day mortality and subgroup analysis evaluating the effect of induction dose on PIH in patients with a shock index (SI) ≥0.9. Statistical analyses included a chi-square test to compare PIH incidence and Cox regression analysis to assess the association between induction agents and 28-day mortality. Multivariable Cox regression was adjusted for mortality by vasopressor initiation or escalation. Fractional polynomial regression was used to evaluate the relationship between induction agent dose and PIH.

A total of 418 patients were included in the analysis, with 222 patients matched in a 1:1 propensity score analysis. The incidence of PIH was 44.1 % in the etomidate group and 53.2 % in the ketamine group (risk difference 9.1 %, 95 % confidence interval [CI] −4.1 to 22.1, p  = 0.179). 28-day mortality was 36.0 % in the etomidate group and 25.2 % in the ketamine group (hazard ratio [HR] 0.66, 95 % CI 0.41–1.07, p  = 0.095). However, in patients who developed PIH and required vasopressors, ketamine was associated with a lower risk of 28-day mortality (adjusted HR 0.59, 95 % CI 0.36–0.97, p  = 0.034). Among patients with SI ≥0.9, a higher induction agent dose was associated with an increased probability of PIH for both etomidate and ketamine.

There was no statistically significant difference in PIH and 28-day mortality between etomidate and ketamine as a single induction agent in elderly patients in the ED.