Identifying the optimal timing of preoperative electroacupuncture for postoperative nausea and vomiting and pain in patients undergoing laparoscopic gynecologic surgery: Study protocol for a randomized controlled trial

Background: Electroacupuncture (EA) has been shown to have antiemetic and analgesic effects; however, optimal timing for the therapy is unclear. Our study aims firstly to investigate the effectiveness and safety of preoperative EA, delivered 24 h before surgery, on postoperative nausea and vomiting (PONV) and postoperative pain in patients undergoing gynecologic laparoscopic surgery; and secondly to identify the optimal timing and dose of stimulation of preoperative EA for preventing PONV and postoperative pain. Methods: This is a single-center, randomized, controlled, four-arm clinical trial. Participants who meet the selection criteria will be randomly assigned to one of the following four groups: Group 1 (EA delivered 24 h before surgery, n = 103), Group 2 (EA delivered 30 min before surgery, n = 103), Group 3 (EA delivered both 24 h before, and 30 min before surgery, n = 103), Group 4 (usual care, n = 103). All groups will receive routine treatment for PONV and pain. EA will be delivered at bilateral Neiguan (PC6) and Zusanli (ST36). The primary outcomes are the incidence of postoperative nausea (PON) and postoperative vomiting (POV), and pain scores at 24 h after the operation. Secondary outcomes include the incidence of PON and POV, and pain scores at 6 h, 48 h and 72 h after the operation, also the severity of PON and POV, consumption of opioid medications, Quality of Recovery-15 (QoR-15), days in hospital and time to passage of first flatus. The assessor and the treating anesthetists will be blinded from group allocation. Participants in the three EA groups are unaware of the purpose of the study. Discussion: An understanding of optimal timing and dosage of preoperative acupuncture will facilitate the implementation of this non-drug therapy and contribute to the overall improvement of post-surgical care