ED90 of Teglidine for Suppressing LMA Insertion Response in the Elderly

This research protocol aims to investigate the 90% effective dose (ED90) of taiglididine for inhibiting laryngeal mask insertion response in elderly patients. It is a non-randomized controlled trial using a biased coin design up-down method (BCD-UDM). A total of 54 elderly patients aged 65-80 years with ASA I-III, BMI 18-30 kg/m², and suitable for urological surgery under general anesthesia with laryngeal mask insertion will be enrolled. The first patient receives an intravenous injection of 1 mg taiglididine, followed by propofol and rocuronium. Subsequent doses of taiglididine are adjusted dynamically based on the previous patient's response: increasing by 0.1 mg if the insertion response is positive, or using BCD-UDM (11% probability to decrease by 0.1 mg, 89% to remain) if negative. The primary efficacy endpoint is the occurrence of laryngeal mask insertion response, while secondary endpoints include adverse events, vital sign changes, insertion success rate, and various time intervals. Safety is evaluated by monitoring vital signs. Statistical analysis will use SPSS 25.0 and R software to calculate ED90 and 95% confidence intervals via probit regression and bootstrap method, with at least 45 valid patients required to complete the trial.