Combined Use of Remimazolam and Propofol in Total Intravenous Anesthesia: A Retrospective Analysis

Abstract

Remimazolam is a newly introduced benzodiazepine anesthetic. Despite being classified as ultrashort-acting, it may cause delayed emergence owing to its not-so-short 80% context-sensitive decrement time. This study retrospectively analyzed 21 patients (12 men and 9 women; median age, 65 years; range, 17–82 years) classified as ASA I or II who underwent general anesthesia with a combination of remimazolam and propofol for anesthesia maintenance during the study period (May 2022 to May 2023). It aimed to determine the optimal effect-site concentrations of remimazolam, propofol, and remifentanil during surgery and recovery times. The population median values of individual median effect-site concentrations for remimazolam, propofol, and remifentanil during adequate sedation (patient state index 25–50) were 0.34 µg/mL, 1.00 µg/mL, and 5.00 ng/mL, respectively. At the recovery of responsiveness, the median values of individual median effect-site concentrations for remimazolam, propofol, and remifentanil were 0.17 µg/mL, 0.53 µg/mL, and 0.88 ng/mL, respectively. There was a significant negative correlation between the individual median propofol effect-site concentrations and age during patient state index range of 25–50. However, no correlation was observed between age and the other effect-site concentrations mentioned above. The patients regained responsiveness at a median of 13 min after termination of anesthetics, except for 2 who required flumazenil before tracheal extubation. Flumazenil was administered to facilitate emergence from sedation in two patients before extubation and in another two after extubation. No adverse events occurred, including resedation or intraoperative awareness. This study demonstrates the potential of combining remimazolam and propofol for effective anesthesia and rapid recovery. To optimize dosing strategies for the combination of remimazolam and propofol, larger prospective pharmacokinetic and pharmacodynamic studies are warranted.