Intraoperative Electroacupuncture Reduces Postoperative Pain, Analgesic Requirement and Prevents Postoperative Nausea and Vomiting in Gynaecological Surgery: A Randomised Controlled Trial

BACKGROUND: Electroacupuncture (EA) is believed to modulate the pain pathway via the release of endogenous opioid substances and stimulation of descending pain inhibitory pathways. In this study, the use of intraoperative 2 Hertz EA stimulation is investigated to determine any opioid-sparing effect and reduction of postoperative nausea and vomiting (PONV) in patients undergoing gynaecological surgery. PATIENT AND METHODS: This was a prospective, double blinded randomized study conducted in a tertiary hospital in Malaysia. Patients (n = 64) were randomly allocated to receive 2 Hertz EA and compared to a control group. EA was started intraoperatively till the end of the surgery (mean duration of surgery was 149.06 ± 42.64 minutes) under general anaesthesia. Postoperative numerical rating scale (NRS), the incidence of nausea, vomiting and usage of rescue antiemetics were recorded at 30 minutes, 2, 4, and 24 hours, respectively. The total morphine demand and usage from the patient-controlled analgesia Morphine (PCAM) were also recorded in the first 24 hours postoperatively. RESULTS: The mean NRS was 2.75 (SD = 2.34) at 30 minutes and 2.25 (SD = 1.80) at 2 hours postoperatively in the EA group that was significantly lower than the mean NRS in the control group as 4.50 (SD = 2.37) at 30 minutes and 3.88 (SD = 2.21) at 2 hours. The mean PCA morphine demand was 27.28 (SD = 21.61) times pressed in the EA group and 55.25 (SD = 46.85) times pressed in the control group within 24 hours postoperatively, which showed a significant reduction in the EA group than the control group. Similarly, total morphine requirement was significantly lower in the EA group with the value of 21.38 (SD = 14.38) mg compared to the control group with the value of 33.94 (SD = 20.24) mg within 24 hours postoperatively. Incidence of postoperative nausea also significantly reduced in the EA group at 30 minutes (15.6%) compared to the control group (46.9%). CONCLUSIONS: It can be concluded that subjects receiving EA intraoperatively experienced less pain and PONV. Hence, it is plausible that EA has an opioid-sparing effect and can reduce PONV.