ED90 of Teglidine for Suppressing LMA Insertion Response in the Elderly

The 90% Effective Dose of Taiglididine for Inhibiting Laryngeal Mask Insertion Response in Elderly Patients

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.

Inclusion Criteria:

1. Aged 65-80 years old.
2. ASA physical status I-III.
3. BMI 18-30 kg/m² (inclusive of critical values).
4. Mallampati class I or II, mouth opening >2.5 cm.
5. No abnormal airway or head/neck conditions.
6. No risk of reflux or aspiration (e.g., full stomach, obesity, gastrointestinal obstruction).
7. Expected surgery duration <180 min.
8. Scheduled for urological surgery requiring general anesthesia and laryngeal mask insertion.
9. Voluntary participation with signed informed consent.

Exclusion Criteria:

Baseline measurements: Severe hypertension (SBP >160 mmHg or DBP >100 mmHg), heart rate <60 bpm or >100 bpm.

2. History of long-term alcohol, sedative, or analgesic use; allergy to any study drugs.

3. Severe dysfunction of vital organs (heart, lung, liver, kidney, nervous system), neuromuscular diseases, hyperthyroidism, obstructive sleep apnea syndrome.

4. History of mental disorders or cognitive impairment severe enough to hinder understanding or cooperation with the study.

5. Preoperative administration of sedative-hypnotics (including benzodiazepines and barbiturates).

6. Upper respiratory tract infection within 1 month before surgery. 7. Participation in other clinical studies within the past 3 months. 8. Other conditions deemed unsuitable for the trial by the investigator.