Effect and placebo effect of acupressure (P6) on nausea and vomiting after outpatient gynaecological surgery

Background: Acupuncture and acupressure have previously been reported to possess antiemetic effect. We wanted to investigate the "true" and placebo effect of acupressure in prevention of postoperative nausea and vomiting (PONV). Patients and methods: Sixty women undergoing outpatient minor gynaecological surgery were entered into a double-blind and randomised study. One group received acupressure with bilateral stimulation of P6 (A), a second group received bilateral placebo stimulation (P) and a third group received no acupressure wrist band and served as a reference group (R). PONV was evaluated as number of patients with complete response (no PONV), nausea only or vomiting. In addition, the need for rescue antiemetic medication and nausea after 24 h was registered. Results: Complete response was obtained in 11, 11 and 9 patients in groups, A, P and R, respectively Nine, 7 and 6 patients had nausea before discharge home, and 1, 1 and 8 patients were nauseated (8 vs 1 patient: P<0.05) 24 h after operation in A, P and R groups, respectively. When compared to placebo acupressure (2 patients vomited and 5 needed rescue), significantly (P<0.05) fewer needed rescue antiemetic medication after acupressure at P6 (no vomiting or rescue medication). When compared to the observation group (5 vomited and 4 needed rescue antiemetics), significantly fewer vomited after acupressure (P<0.05) Conclusion: In patients undergoing brief gynaecological surgery, placebo effect of acupressure decreased nausea after 24 h but vomiting and need of resuce antiemetics was reduced only by acupressure with the correct P6 point stimulation.