Six RCTs (n=649) were included in the review. The minimum Oxford quality scale score was 4 and the maximum score recorded by two trials was 6 (from a possible 7). The studies were heterogeneous with regard to interventions, placebo band treatments and timing of treatment delivery.
Nausea: Of the five trials that reported on the incidence of intra-operative nausea, two reported a significant reduction with the use of P6 stimulation. The remaining three trials reported no differences between the intervention and control groups. Of the four trials that reported data for post-operative nausea, only one trial reported a reduction in the incidence of post-operative nausea with P6 stimulation (3% compared to 43%, p<0.05).
Vomiting: there were no statistically significant differences in the incidence of intra-operative vomiting with P6 stimulation (five trials). Two trials reported a statistically significant reduction on post-operative vomiting with P6 stimulation.
Use of rescue medication: Of the four trials reporting on the need for rescue antiemetics during and after surgery, one trial reported a significant reduction in antiemetic requirement during surgery with P6 stimulation.
Complete response to therapy: the only study that reported data on the rate of intra-operative and post-operative complete response found no differences between the P6 stimulation and control groups for this outcome.
There were no statistically significant differences between the intervention and control groups for the other outcomes examined.