Anaesthetic induction with etomidate in cardiac surgery: A randomised controlled trial.

Background: Etomidate is perceived as preserving haemodynamic stability during induction of anaesthesia. It is also associated with adrenocortical dysfunction. The risk/benefit relationship is controversial.

Objectives: We tested the hypotheses that single-dose etomidate increases cumulative vasopressor requirement, time to extubation and length of stay in the ICU.

Design: Double-blind randomised controlled trial.

Setting: Bern University Hospital, Switzerland, from November 2006 to December 2009.

Patients: There were 90 patients undergoing coronary artery bypass grafts (CABG) and 40 patients undergoing mitral valve surgery (MVS). Reasons for noninclusion were known adrenocortical insufficiency, use of etomidate or propofol within 1 week preoperatively, use of glucocorticoids within 6 months preoperatively, severe renal or liver dysfunction, or carotid stenosis.

Interventions: CABG patients were allocated randomly to receive either etomidate 0.15 mg kg with placebo, propofol 1.5 mg kg with placebo or etomidate 0.15 mg kg with hydrocortisone (n = 30 in each arm). Risk stratification (low vs. high) was achieved by block randomisation. MVS patients received either etomidate 0.15 mg kg or propofol 1.5 mg kg (n = 20 in each arm).

Main Outcome Measures: Cumulative vasopressor requirements, incidence of adrenocortical insufficiency, length of time to extubation and length of stay in ICU.

Results: Cumulative vasopressor requirements 24 h after induction did not differ between treatments in patients who underwent CABG, whereas more noradrenaline was used in MVS patients following propofol induction (absolute mean difference 5.86 μg kg over 24 h P = 0.047). The incidence of relative adrenocortical insufficiency was higher after etomidate alone than propofol (CABG 83 vs. 37%, P < 0.001; MVS: 95 vs. 35%, P < 0.001). The time to extubation, length of stay in ICU and 30-day mortality did not differ among treatments. Within low and high-risk subgroups, no differences in vasopressor use or outcomes were found.

Conclusion: In elective cardiac surgery, laboratory indicators of etomidate-induced adrenal insufficiency do not translate into increased vasopressor requirement or inferior early outcomes.

Trial Registration: ClinicalTrials.gov Identifier: NCT 00415701.