Acupuncture in Preventing Postoperative Nausea and Vomiting: Efficacy of Two Acupuncture Points Versus a Single One

This double-blind randomized controlled trial investigated whether the combination of two acupuncture points would be more effective than a single point in preventing postoperative nausea and vomiting. Conducted at Imam Khomeini Hospital in Tehran, Iran, between June 2011 and June 2012, the study enrolled 227 patients undergoing elective surgery under general anesthesia. Inclusion criteria covered patients with ASA I or II classification, surgeries lasting 1-2 hours, excluding eye or ear operations. Patients who had used steroids in the previous month, with surgeries longer than 2 hours or a history of motion sickness, were excluded.

Participants were randomized into two groups: 112 patients received acupuncture only at the PC-6 (Neiguan) bilateral point, while 115 patients received combined acupuncture at the PC-6 and LI-4 (Hegu) bilateral points. All acupuncture procedures were performed by an experienced acupuncturist immediately after anesthetic induction, with sterile needles kept in place throughout the surgery. The anesthetic protocol was standardized for all patients, including induction with sodium thiopental, atracurium, and lidocaine, followed by maintenance with propofol, fentanyl, and ventilation with oxygen and nitrous oxide. Randomization was performed by a computerized program, ensuring that surgeon, patients, and investigator remained blinded to the study groups.

Assessment of nausea and vomiting was performed subjectively by a trained nurse blinded to the study during the first 24 postoperative hours. The results demonstrated a statistically significant difference between the groups. In the combined group (PC-6 + LI-4), 51.3% of patients had nausea compared with 75% in the single group (PC-6 only), representing a significant reduction (p<0.05). Regarding vomiting, only 18.3% of patients in the combined group had this symptom versus 34.8% in the single group, also statistically significant (p<0.05).

There were no significant demographic differences between the groups, including age, sex, type of surgery, and early postoperative complications. The clinical implications suggest that adding the LI-4 point to the traditionally used PC-6 may offer additional benefit in preventing postoperative nausea and vomiting. The PC-6 point, located 5 cm proximal to the distal wrist crease, has a recognized antiemetic effect, while LI-4, traditionally used for pain management, demonstrated in this study a complementary effect. The authors propose that this combination represents an advance in perioperative integrative medicine, offering an alternative with fewer adverse effects than conventional antiemetic medications.

The proposed mechanism of action includes possible gastric stimulation promoting emptying and increasing intestinal motility, although the exact mechanism remains incompletely understood.