90% Effective Infusion Time of Sufentanil to Prevent Induction Cough: A Biased Coin Sequential Study

Overview

This single-center, prospective biased coin up-and-down sequential study aims to determine the 90% effective infusion time (ET90) of sufentanil to prevent sufentanil-induced cough (SIC) during the induction phase of general anesthesia in adults undergoing endotracheal intubation. Two age cohorts are studied separately: younger adults (\<65 years) and older adults (≥65 years). The trial does not test superiority or between-group differences as the primary objective. All participants receive sufentanil via a peripheral intravenous pump. The total sufentanil dose is fixed within each age cohort (young: 0.40 μg/kg; elderly: 0.30 μg/kg), while the pump injection time is adjusted using the biased coin up-and-down allocation method. SIC success is defined as no audible cough within a prespecified observation window from the start of the infusion until 2 minutes after infusion ends. The primary outcome is the ET90 of sufentanil and its 95% confidence interval for each age cohort, estimated using centered isotonic regression with bootstrap confidence intervals. Approximately 120 patients will be screened to obtain at least 54 evaluable participants per cohort.

This is a single-center, prospective sequential study using a biased coin up-and-down allocation approach to determine the 90% effective infusion time (ET90) of sufentanil during the induction phase of general anesthesia to prevent sufentanil-induced cough (SIC). The study evaluates two age groups separately: younger adults (\<65 years) and older adults (≥65 years). Sufentanil will be administered intravenously via a infusion pump. Within each age cohort, the total sufentanil dose is predetermined, while the infusion time (rate) is adjusted based on the previous participant's outcome according to the biased coin up-and-down rule. The primary success criterion is the absence of SIC during a prespecified observation period that starts at sufentanil infusion initiation and ends shortly after infusion completion during the induction phase. The primary outcome is the ET90, estimated for each age cohort with an appropriate statistical model using the observed infusion times and SIC outcomes. Participants are screened before surgery based on age and general anesthesia requirements, and key comorbidities and contraindications are considered to reduce confounding. Safety is monitored throughout the induction phase and perioperative period, with attention to potential adverse events including hemodynamic instability and respiratory depression. Approximately 120 patients are planned for enrollment to obtain sufficient evaluable participants in each cohort for ET90 estimation.