Effect of transcutaneous auricular vagus nerve stimulation on postoperative gastrointestinal dysfunction in patients with gynecological abdominal or pelvic tumors: a study protocol for a prospective, single-center, randomized, controlled clinical tri

BACKGROUND: Postoperative gastrointestinal dysfunction (POGD) commonly presents with nausea, vomiting, abdominal distension, delayed flatus or stool, and prolonged intolerance to oral intake. It can cause postoperative pain, delayed gastrointestinal motility, or intestinal obstruction requiring secondary surgery, imposing substantial physical, emotional, and economic burdens. Transcutaneous auricular vagus nerve stimulation (taVNS), a non-invasive brain-gut axis modulator, may promote postoperative gastrointestinal recovery. This study will assess the efficacy and safety of taVNS in reducing the incidence of POGD after gynecological abdominal or pelvic tumor surgery. METHODS AND ANALYSIS: This randomized, single-center, controlled trial will enroll 210 patients scheduled for gynecological abdominal or pelvic tumor surgery and randomly assign them 1:1 to taVNS or sham-taVNS (n = 105 each). The primary outcome is the incidence of POGD within three days after surgery, assessed by the Intake, Feeling nauseated, Emesis, Exam, and Duration of symptoms (I-FEED) scoring system. Secondary outcomes include time to first flatus, time to first bowel movement, incidence and severity of postoperative nausea and vomiting, time to first ambulation, time to first oral intake, incidence of postoperative delirium, and postoperative pain intensity. ETHICS AND DISSEMINATION: The Ethics Committee of Huzhou Central Hospital approved this study (approval no. 202503014-03). Findings will be disseminated at national anesthesiology conferences and published in peer-reviewed journals. TRIAL REGISTRATION: ChiCTR2500104412 (Chinese Clinical Trial Registry, http://www.chictr.org.cn; registered June 17, 2025).