The relationship between perioperative nausea and vomiting and serum serotonin concentrations in patients undergoing cesarean section under epidural anesthesia

BACKGROUND: Serotonin-also known as 5-hydroxytryptamine or 5-HT-can induce nausea and vomiting (NV) by peripheral mechanisms via the activation of 5-HT(3) receptors. In this study, we observed perioperative NV, including intraoperative NV, and changes in serum 5-HT concentrations. We evaluated the relationship between perioperative NV and serum 5-HT levels in patients undergoing cesarean section under epidural anesthesia, and carried out a pilot study to determine if further studies on a larger scale were justified. METHODS: Twenty-eight patients who were scheduled for cesarean section under epidural anesthesia were included in the study. Patients were assigned to 2 groups according to the occurrence of NV after induction, i.e., an NV-positive or an NV-negative group. Serum 5-HT concentrations were measured before induction, at the time that NV occurred (in the case of the NV-positive group) or 5 min after the umbilical cord clamping (in the case of the NV-negative group) during surgery, and at 2 h postoperatively. RESULTS: NV occurred in 10 of the 28 patients. No significant differences in serum 5-HT concentrations were found within or between the two groups. CONCLUSIONS: This study suggests that there is no correlation between serum 5-HT concentration and the occurrence of perioperative NV in patients undergoing cesarean section under epidural anesthesia, and the findings do not seem to support further investigations regarding a possible relationship between serum 5-HT concentration and perioperative NV.