Study design and participants
A randomized, double-blind, placebo-controlled clinical trial was conducted in the ambulatory surgery centre of the First Affiliated Hospital of Anhui Medical University. The trial plan was approved by the ethics committee of the First Affiliated Hospital of Anhui Medical University (PJ2022-02-34). The study was registered in the Chinese Clinical Trial Registry (ChiCTR220055551, Principal Investigator: Y.L.) on 12 January 2022. Written informed consent was obtained from each patient and the study took place between 11 February 2022 and 20 June 2022.Inclusion criteria included: age 18–65 years, ASA classification I–II, BMI of 18–30 kg/m