Perhaps the most common problem experienced by patients after surgery is nausea and vomiting, caused by the anaesthesia. In some studies, as many in four in every five patients have been found to suffer this unpleasant side effect in the absence of strategies to prevent it. The nausea and vomiting can also cause more serious complications, including dehydration, or the tearing open of the surgical wound.

Drugs, called antiemetics, can be used to prevent nausea and vomiting in patients who are thought to be at high risk, or as a treatment to ease the symptoms. Alternatives have also been investigated and an updated Cochrane review found that one of these, stimulation of the acupuncture point on the wrist called P6, was effective.

The P6 acupoint is a couple of inches from the wrist crease between two tendons. It can be stimulated by acupuncture with a needle, and also by electro-acupuncture, transcutaneous nerve stimulation, laser stimulation and acupressure wristbands.

In the original version of the Cochrane review, the authors were able to include 26 trials. Five years on, the number of trials has increased to 40 and the number of patients to nearly 5000. In the included trials, stimulation of the P6 acupoint was compared with either a sham or placebo treatment, or with an antiemetic drug. In total, the review drew on research into ten different methods of P6 stimulation, and five different antiemetic drugs had been used for comparison.

When the authors of the updated review combined the results from the trials that compared stimulation of the P6 acupoint with sham treatment, they found clear benefits for the stimulation. The proportion of patients who experienced some nausea or vomiting fell from about 80% in the control group to 25% in the stimulation group. P6 acupoint stimulation also fared well when compared with antiemetics. Both interventions were beneficial and there was no statistically significant difference between the outcomes for the two patient groups.

The authors of the review also investigated whether P6 acupoint stimulation had its own side effects, which would need to be considered alongside the reduction in nausea and vomiting side effects from the anaesthesia. They found that patients did experience some problems, but these tended to be self-limiting and relatively minor. For example, if needle acupuncture was used, patients might develop redness or irritation at the puncture site. Some patients felt tired after electro-acupuncture, while wristbands caused red indentation, itching and blistering.

This Cochrane review is available in full at www.mrw.interscience.wiley.com/cochrane/clsysrev/articles/CD003281/frame.html

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June 22 2009