Effect of transcutaneous auricular vagus nerve stimulation on postoperative sleep quality in older patients undergoing laparoscopic cholecystectomy: protocol for a prospective, randomised, double-blind, controlled trial.

INTRODUCTION: Postoperative sleep disturbances (PSDs) are highly prevalent in older surgical patients, leading to impaired recovery and increased complications. Transcutaneous auricular vagus nerve stimulation (taVNS) is a non-invasive neuromodulation technique. This study aims to evaluate the efficacy of perioperative taVNS in reducing the incidence of PSD in older adults undergoing laparoscopic cholecystectomy (LC). METHODS AND ANALYSIS: This is a single-centre, prospective, randomised, double-blind, sham-controlled trial. A total of 210 patients aged 66-79 years scheduled for elective LC will be enrolled. Participants will be randomly allocated (1:1) to receive either active taVNS (25 Hz, 200 μs pulse width, cyclic 30 s on/off) at the left cymba conchae or identical sham stimulation without electrical current. The intervention will be applied throughout the intraoperative period and repeated 30 min on postoperative day 1. The primary outcome is the incidence of PSD on postoperative day 2. Secondary outcomes include PSD incidence on postoperative days 1 and 3, anxiety and depression scores, postoperative pain and analgesic consumption, quality of recovery and adverse events. ETHICS AND DISSEMINATION: The study protocol has been approved by the Ethics Committee of Ningbo No.2 Hospital (Approval No. PJ-NBEY-KY-2025-195-02). It is registered with the Chinese Clinical Trial Registry (Registration number: ChiCTR2500110972). Written informed consent will be obtained from all participants. The findings will be submitted for publication in a peer-reviewed journal. TRIAL REGISTRATION NUMBER: ChiCTR2500110972.