Does Low Dose Ketamine or Etomidate Prevent Post-Induction Hypotension in Unstable Patients?
August 21, 2023
Written by Joshua Campbell
There is no association between the weight-based drug dose of etomidate or ketamine and post-intubation hypotension.
Does sedative dose matter?
Experts have long recommended reducing the dose of sedative used during RSI in hemodynamically unstable patients to reduce the risk of worsening post-intubation hypotension, despite little data to support this practice. This study used a multi-variable analysis of the NEAR (National Emergency Airway Registry) to determine if reducing the dose of sedative led to decreased hypotension.
12,175 intubations with etomidate and 1,849 intubations with ketamine were analyzed, with post-intubation hypotension being defined as <100mmHg SBP in the 15 minutes following intubation. Patients 14 years or older and on the first intubation attempt were analyzed. Hypotension occurred in 1,976 patients with etomidate and 537 patients with ketamine. For etomidate, the average dose without hypotension was 0.28mg/kg and 0.27mg/kg with hypotension. For ketamine, average dose was 1.34mg/kg without hypotension and 1.32mg/kg with hypotension. In the multivariable analysis, neither drug was independently associated with post-induction hypotension.
Importantly, this study was limited by the potential confounding of physician judgment about dose selection and which patients they may have considered to be at higher risk of post-intubation hypotension. This makes it difficult to discern the true effect of the sedative dose. However, this was mitigated by comparing sites that used a uniform 20mg of etomidate for all-comers in which no difference was seen in hypotension.
How will this change my practice?
I will continue to use weight-based dosing during intubations and not decrease my dose based on this study. With outcomes being nearly identical, the benefits of weight-based dosing (decreased awareness during post-intubation paralysis) will continue to play an important role in my dosage selection. Future prospective studies would be beneficial, especially those including patient-centered outcomes such as paralysis awareness.
Reviewed and edited by Clay Smith
Sedative Dose for Rapid Sequence Intubation and Postintubation Hypotension: Is There an Association? Ann Emerg Med. 2023 Jun 30;S0196-0644(23)00379-7. doi: 10.1016/j.annemergmed.2023.05.014. Online ahead of print.