Background and Goals: Acupuncture at P6-point (volar anterior ante-brachial region) during gynecologic surgery reduces the incidence of postoperative nausea and vomiting (PONV) (1). Transcutaneous electrical stimulation of P6-point reduced nausea, but not vomiting after cholecystectomy (2). In this RCT we used a conventional neuromuscular stimulator to measure neuromuscular blockade for the stimulation of the ulnar nerve or the median nerve at the P6- point to determine the incidence of PONV.
Materials and Methods: We planned to evaluate 220 ASA I-III women undergoing elective laparoscopic surgery under standardized anesthesia upon the incidence of PONV during the first 24 hours. Besides demographic data and standard anesthesia safety monitoring, severity of nausea and vomiting, pain-score, rescue anti-emetic medication were recorded for the early (first 6-h) and late (6-24-h) postoperative period.
In half of the patients neuromuscular blockade was monitored with a nerve stimulator (TOF-watchS, Organon, NL) above the ulnar nerve at the wrist in single twitch mode (1-Hz). The aim of neuromuscular blockade during surgery was 10% of the twitch height of the baseline reading. The intervention group was stimulated as described above at the P6-point above the median nerve.
Results and Discussions: From 60 patients studied (out of 220 planned). Demographic data, intra- and postoperative hemodynamic measurements and medication, pain score and rescue medication was comparable between the 2 groups and the 2 time periods. The overall PONV incidence was 40% over 24-h and 32% in the first 6-h. Stimulation of the P6 point reduced PONV significantly (15% vs. 54%; P < 0.05) and nausea (11% vs. 46%; P < 0.05) but not vomiting in the 1st 6-h after surgery. No difference was found for the late postoperative period.
Conclusion(s): Continuous intraoperative transcutaneous stimulation of the P6 acupuncture point at the volar side of the wrist with a conventional nerve stimulator for the monitoring of neuromuscular blockade in the single twitch mode reduces PONV and nausea in the 1st 6-h after surgery.
1 Dundee JW. Br J Anaesth 1989; 63: 612-18.
2 Zarate E. Anesth Analg 2001; 92: 629-35.