Abstract / Summary
Background Postoperative nausea and vomiting (PONV) remains a frequent and distressing complication after gynecologic laparoscopic surgery, with residual incidence approaching 30-40% despite contemporary multimodal antiemetic prophylaxis. Transcutaneous auricular vagus nerve stimulation (taVNS) is a noninvasive neuromodulation technique that activates auricular vagal afferents projecting to brainstem nuclei implicated in emetic reflexes. We present the protocol of a randomized trial to evaluate taVNS as an adjunctive, nonpharmacologic strategy to reduce PONV in this high-risk population. Methods This single-center, prospective, randomized, double-blind, sham-controlled, parallel-group superiority trial will enroll 146 adult women undergoing elective gynecologic laparoscopy under general anesthesia. Participants will be randomized 1:1 to active taVNS or sham stimulation, with stratification by Apfel risk score ([≤]2 vs. [≥]3). Two 30-minute sessions will be delivered: one beginning 30 minutes before anesthesia induction and another 30 minutes after arrival in the post-anesthesia care unit. The primary outcome is the incidence of PONV within 48 hours postoperatively. Secondary outcomes include nausea severity (11-point numerical rating scale), time to first PONV episode, number of vomiting/retching episodes, rescue antiemetic use, postoperative pain intensity, cumulative opioid consumption (morphine equivalents), Quality of Recovery-15 scores at 24 and 48 hours, and gastrointestinal recovery indices. Analyses will follow intention-to-treat and per-protocol principles; missing data will be addressed via multiple imputation. Conclusions This trial aims to provide rigorous evidence on the efficacy and safety of perioperative taVNS for PONV prevention in women undergoing gynecologic laparoscopy. If proven effective, taVNS could be integrated into enhanced recovery after surgery (ERAS) pathways as a mechanistically grounded, nonpharmacologic adjunct to standard antiemetic regimens. Trial registration Chinese Clinical Trial Registry ChiCTR2600115965 (prospectively registered).