Seizure after flumazenil reversal for total intravenous anaesthesia with remimazolam versus propofol: a matched retrospective cohort analysis of a large Japanese nationwide inpatient database.

BACKGROUND

Remimazolam is a novel anaesthetic and sedative agent that offers several advantages, including minimal adverse haemodynamic effects and availability of a specific antidote, flumazenil. Flumazenil can induce seizures as an adverse effect; however, the incidence of seizures after flumazenil reversal after total intravenous anaesthesia with remimazolam (remimazolam-flumazenil) remains unknown. We compared the risk of seizures between total i.v. anaesthesia with remimazolam-flumazenil or propofol.

METHODS

We retrospectively identified patients who underwent elective surgery (excluding brain surgery) with total i.v. anaesthesia in Japan between April 2020 and March 2022 using the Japanese Diagnosis Procedure Combination database. Patients were divided into remimazolam-flumazenil and propofol groups. Patients in the remimazolam-flumazenil group were matched to those in the propofol group at a variable ratio of 1:3 (maximum) based on age, sex, hospital, and type of surgery. We conducted conditional logistic regression analyses to assess the association between total i.v. anaesthesia with remimazolam-flumazenil and the incidence of perioperative seizures.

RESULTS

We identified 12 033 patients who underwent total i.v. anaesthesia with remimazolam-flumazenil and 432 275 patients with propofol, creating a matched cohort of 19 105. The crude incidence of seizures was 0.66% (95% confidence interval, 0.63-0.68%). There was no significant difference in seizures between the two groups (adjusted odds ratio, 1.08; 95% confidence interval, 0.49-2.37).

CONCLUSIONS

We observed no significant differences in perioperative seizures between remimazolam-flumazenil and propofol in patients undergoing non-neurological surgery. This suggests that remimazolam-flumazenil is a possible alternative to total i.v. anaesthesia with propofol.