Sample size
The primary endpoint of this study was the consumption of sufentanil at 24 hours after surgery. We used a two-tailed test with α = 0.05 and β = 0.1 based on the pre-experimental 24-hour postoperative sufentanil consumption in groups S (95.1 ± 5.5) and C (99.3 ± 7.0), with a minimum of 60 patients required in each group. Ultimately, each group included 75 patients, taking into account a 20% attrition rate.