OBJECTIVETo observe the effect of transcutaneous acupoint electric stimulation on the postoperative nausea and vomiting (PONV) and explore its mechanism.

METHODSNinety cases of elective cesarean section of I to II grade in American Society of Anesthesiologists (ASA) were collected and randomized into a transcutaneous acupoint electric stimulation group (group A), a sham-acupoint group (group B) and a blank control group (group C), 30 cases in each one. In the group A, 30 min before operation, the transcutaneous electric stimulation was applied to bilateral Neiguan (PC 6) and Zusanli (ST 36). The stimulation lasted during operation and 1 h after operation. In the group B, the same electric stimulation was given at the sites 3 cm lateral to the medial sides of Neiguan (PC 6) and Zusanli (ST 36). In the group C, the electric plaster was attached to bilateral Neiguan (PC 6) and Zusanli (ST 36), without any electric stimulation. The lumbar epidural combined anesthesia and the postoperative analgesia were same in each group. The mean arterial pressure (MAP), heart rate (HR) , oxygen saturation of blood (SpO2) and the VAS (visual analogue scale) score of nausea and vomiting were recorded before acupoint stimulation (T0), at skin incision (T1), fetal delivery (T2), abdominal exploration (T3) and 1 h after operation (T4) as well as bleeding and application of oxytocin, ephedrine and atropine during operation separately. The changes of plasma 5-hydroxytryptamine (5-HT) concentration were observed at T0 and 30 min after electric stimulation.

RESULTSThe differences were not significant in MAP, HP and SpO2 at each time point of the three groups (all P> 0.05). The differences were not significant in bleeding and application of oxytocin, ephedrine and atropine during operation (all P > 0.05). The scores of nausea and vomiting in the group A during T1 to T4 were lower than those in the group B and group C (all P < 0.05). In the group A, 30 min after transcutaneous acupoint electric stimulation, plasma 5-HT concentration was lower than those in the group B and group C (both P < 0.01).

CONCLUSIONThe transcutaneous acupoint electric stimulation apparently relieves nausea and vomiting during and after cesarean section and the mechanism is relevant with the decrease of plasma 5-HT concentration.