Dosing RSI meds in Obesity

“Accuracy of rapid sequence intubation medication dosing in obese patients intubated in the ED”

Bhat, R., Mazer-Amirshah M. Am J Emer Med Dec 2016

Objective: to compare rates of inappropriate dosing of medications in obese and nonobese patients during rapid sequence intubation (RSI)

Methods: Retrospective review of endotracheal intubations. Patients were excluded if they were intubated in the field, did not receive intubation medications, or did not have complete data. Appropriate dosing was defined as succinylcholine 1-1.5mg/kg total body weight and etomidate 0.2-0.4mg/kg total body weight.

519 patients were retrospectively analyzed at an urban, tertiary care, academic ED in the United States.

Results:  Of the patients studied, 29.3% were found to be obese and 70.7% nonobese.  In total, 56% received an inappropriate succinylcholine dose, 24% received an inappropriate etomidate dose


Obese patients were more likely to be underdosed

Succinylcholine – OR 63.7 (95% confidence interval [CI], 17.8-228.1)

Etomidate – OR 178.3 (95% CI, 37.6-844.7)

Nonobese patients were more likely to be overdosed

Succinylcholine – OR 62.5 (95% CI, 17.9-250)

Etomidate – OR 166.7 (95% CI, 37.0-1000)



The goal of this study was to demonstrate that the obese population in the ED routinely receives inappropriate RSI dosing. The study suggests that this may be due to unavailability of patient weight during an emergent airway situation or physicians use a standard dose in all patients. While the study does not examine outcomes, it does point out some of the dangers of under or overdosing. Under dosing can make intubating more difficult and overdosing can result in increased drug side effects.

The findings of this study aren’t too unexpected- this study mostly serves as a reminder that succinylcholine and etomidate are weight based dosing and special consideration is needed in the obese population.  In an already challenging population, optimizing your RSI dosing may help your first pass chances.


– Skylar Trott