Transcutaneous electrical acupoint stimulation versus sham stimulation and dexamethasone versus amisulpride for preventing postoperative nausea and vomiting after laparoscopic gynecologic surgery: protocol for a randomized 2 × 2 factorial trial

Background Postoperative nausea and vomiting (PONV) remains a common complication after gynecologic laparoscopic surgery. Although multimodal prophylaxis is recommended, clinical practice still relies largely on pharmacologic interventions. Transcutaneous electrical acupoint stimulation (TEAS) at the P6 acupoint may have potential benefit for PONV prevention. However, its effectiveness when incorporated into pharmacologic prophylaxis, and whether its effect varies according to the antiemetic used, remain unclear. This trial aims to evaluate the effect of P6-TEAS on PONV prevention in patients receiving dexamethasone or amisulpride. Methods This multicenter, prospective, randomized, sham-controlled, 2 × 2 factorial trial will enroll 212 women undergoing gynecologic laparoscopic surgery under general anesthesia. Participants will be randomly assigned in a 1:1:1:1 ratio to receive one of four treatment combinations: TEAS plus dexamethasone, TEAS plus amisulpride, sham stimulation plus dexamethasone, or sham stimulation plus amisulpride. TEAS or sham stimulation will be delivered at the P6 acupoint in two 1-h sessions, before surgery and at 24 h after surgery. The primary outcome will be the incidence of PONV within 48 h after surgery. Secondary outcomes will include PONV-related symptoms and severity, use of rescue antiemetics, opioid consumption, pain scores, recovery milestones, patient satisfaction, QoR-15 scores, and length of hospital stay. Safety outcomes will include adverse events related to TEAS or study drugs and perioperative hemodynamic events requiring treatment. Discussion This trial will evaluate P6-TEAS versus sham stimulation as the primary comparison and provide exploratory estimates for the dexamethasone-versus-amisulpride comparison and the TEAS-by-drug interaction. The findings may inform integrated prevention strategies for PONV after gynecologic laparoscopic surgery. Clinical Trial Registration https://clinicaltrials.gov/study/NCT07631910 , identifier NCT07631910.