Effect of P6 acustimulation on post-operative nausea and vomiting in patients undergoing a laparoscopic cholecystectomy.

BACKGROUND

Non-pharmacologic techniques such as electrical acustimulation may mitigate post-operative nausea and vomiting (PONV). The primary purpose of this study was to investigate the effectiveness of acustimulation on attenuating PONV. Moreover, we tested whether a pre- or a post-induction application of acustimulation results in differences in PONV reduction.

METHODS

In this prospective, double-blind, randomized, controlled trial, we studied 200 patients undergoing a laparoscopic cholecystectomy during propofol (induction) fentanyl/isoflurane/atracurium (maintenance) anaesthesia. In the acustimulation group (n=101), subdivided into groups with pre-induction (n=57) and post-induction (n=44) acustimulation, an active ReliefBand device was placed at the P6 acupoint. In the sham group (n=99), also subdivided into pre-induction (n=55) or post-induction (n=44) groups, an inactive device was applied instead. The ReliefBand remained in place for 24 h after surgery. Nausea and vomiting/retching were recorded at 2, 6, and 24 h post-operatively.

RESULTS

The incidence of early nausea (up to 2 h) was significantly lower in the acustimulation than in the sham group (29% vs. 42%; P=0.043). No significant effect could be detected for retching/vomiting. Moreover, acustimulation showed no effect on PONV after 6 and 24 h. Risk factor analysis (female gender, non-smoker, history of PONV/motion sickness, and post-operative morphine usage) revealed a relative reduction in risk of 40% for nausea (P=0.021) and 55% for retching/vomiting (P=0.048) in patients with three or four risk factors present. The timing of (pre- vs. post-induction) acustimulation had no significant effect on PONV reduction.

CONCLUSION

Acustimulation at the P6 acupoint reduces early nausea, but not vomiting, after laparoscopic cholecystectomy, irrespective of its pre- or post-induction application.