Hypotension after induction of anesthesia with remimazolam or etomidate: a non-inferiority randomized controlled trial in patients undergoing coronary artery bypass grafting

Abstract

Background: Remimazolam is a novel ultra-short-acting benzodiazepine known for its hemodynamic stability over propofol. However, its hemodynamic effects compared to those of etomidate are not well established. This study aimed to determine whether the use of remimazolam is non-inferior to etomidate with regard to the occurrence of post-induction hypotension in patients undergoing coronary artery bypass grafting.

Methods: Patients were randomly assigned to either the remimazolam group (6 mg/kg/h) or the etomidate group (0.3 mg/kg) for induction of anesthesia. Anesthetic depth was adjusted based on the bispectral index. Primary outcome was the incidence of post-induction hypotension, defined as a mean arterial pressure less than 65 mmHg within 15 min after endotracheal intubation, with a non-inferiority margin of 12%.

Results: A total of 144 patients were finally analyzed. Incidence of post-induction hypotension was 36/71 (50.7%) in the remimazolam group and 25/73 (34.2%) in the etomidate group, with a rate difference of 16.5% (95% CI [3.0-32.6]) between the two groups that was beyond the prespecified non-inferiority margin of 12.0%. The number of patients who needed vasopressors was similar in the two groups.

Conclusions: In this non-inferiority trial, remimazolam failed to show non-inferiority to etomidate in terms of post-induction hypotension when used as an induction drug for general anesthesia in patients undergoing coronary artery bypass grafting. However, different doses or infusion techniques of remimazolam should be compared with etomidate in various patient groups to fully assess its hemodynamic non-inferiority during induction of anesthesia.

Keywords: Blood pressure; Cardiovascular anesthesia; Etomidate; Hemodynamics; Hypotension; Remimazolam..

Fig. 1.

Consolidated Standards of Reporting Trials (CONSORT) diagram.

Fig. 2.

Non-inferiority diagram illustrating the absolute risk reduction in the incidence of hypotension between the etomidate and remimazolam groups over the first 15 minutes after anaesthetic induction. A vertical dotted line indicates a non-inferiority margin of 12%. Reversed triangle, triangle, square, and rhombus indicates hypotension incidence differences, and the error bars indicate the 95% CI of the incidence difference between groups. MAP: mean arterial pressure.

Fig. 3.

Comparison of the highest and the lowest MAP during the 15-minute study period between the etomidate group (gray, circle) and the remimazolam group (blue, square). Initial = MAP before anaesthetic induction; Highest = highest MAP value during the 15-minute study period; Lowest = lowest MAP value during the 15-minute study period. *P value was statistically significant. MAP: mean arterial pressure.