The effective sedative dose of remimazolam for BIS <60 during general anesthesia induction between elderly and non-elderly patients-A randomized controlled trial.

Background: There is lack research about the effect of sufentanil on the effective dose of remimazolam during general anesthesia in both elderly and non-elderly patients scheduled for day surgery. This study was conducted to estimate the 95% effective dose (ED95) of remimazolam with low dose of sufentanil for BIS <60 during general anesthesia in both elderly and non-elderly patients scheduled for day surgery. Methods: Patients scheduled for elective gynecological day procedures were randomly allocated to one of four dosage groups receiving 0.1, 0.2, 0.3, or 0.4 mg/kg of remimazolam, with 25 participants per group. All patients received a concurrent intravenous dose of sufentanil (0.1 μg/kg) during anesthesia induction. Successful sedation was defined as achieving a BIS score of <60 within 5 minutes of remimazolam administration. The ED50 and ED95 of remimazolam for BIS <60 during general anesthesia induction were calculated. Secondary outcomes included the incidence of hypotension, respiratory depression, and adverse events. Results: In elderly patients, the estimated ED50 of remimazolam was determined to be 0.156 mg/kg, with a 95% confidence interval (CI) ranging from 0.110 to 0.190 mg/kg. For non-elderly individuals, the corresponding ED50 was 0.218 mg/kg (95% CI: 0.179-0.253 mg/kg). Additionally, the dose required to achieve 95% efficacy (ED95) was calculated as 0.336 mg/kg (95% CI: 0.286-0.437 mg/kg) in the elderly cohort and 0.418 mg/kg (95% CI: 0.361-0.528 mg/kg) in the non-elderly cohort. Hypotension occurred significantly more often in elderly patients (P < 0.05), but not for the incidence of bradycardia or respiratory depression between groups (P > 0.05). Conclusion: Under BIS monitoring during gynecological day surgery, the estimated ED95 of remimazolam with 0.1 μg/kg sufentanil was 0.336 mg/kg (95% CI: 0.286-0.437 mg/kg) for elderly patients and 0.418 mg/kg (95% CI: 0.361-0.528 mg/kg) for non-elderly patients. Clinical Trial Registration: This study is registered with ClinicalTrials.gov as ChiCTR2400091138.