Median effective dose of sufentanil combined with remimazolam for suppressing the response to tracheal intubation: A prospective dose-finding study using Dixon's up-and-down method.

To ascertain the median effective dose (ED50) and 95% effective dose (ED95) of a combination of sufentanil and remimazolam for suppressing the tracheal intubation response in patients receiving general anesthesia and to assess the hemodynamic stability and incidence of adverse events related to this drug regimen, this prospective dose-finding study used Dixon's up-and-down sequential method. Thirty-one patients scheduled for surgery under general anesthesia between October 2023 and December 2023 were assessed for eligibility; 7 were excluded, and 24 completed the dose-finding sequence and were analyzed (12 with a negative and 12 with a positive intubation response). Anesthesia was induced with remimazolam 0.35 mg/kg, followed by sufentanil at an initial dose of 0.4 µg/kg, with subsequent dose adjustments based on the intubation response. The primary endpoint was the ED50 of sufentanil, and secondary endpoints included hemodynamic indices and adverse events. The ED50 and ED95 of sufentanil required to suppress the tracheal intubation response were 0.358 µg/kg (95% confidence interval, 0.340-0.376 µg/kg) and 0.436 µg/kg (95% CI, 0.409-0.504 µg/kg), respectively. Heart rate did not differ significantly between response groups. Mean arterial pressure at T2 and the incidence of hypertension were higher in the positive-response group. When remimazolam 0.35 mg/kg was used for induction, the ED50 and ED95 of sufentanil for suppressing the tracheal intubation response were 0.358 and 0.436 µg/kg, respectively. These estimates should be interpreted within the study population and dose-finding design.