Nausea and vomiting after laparoscopic surgery are not associated with an increased peripheral release of serotonin.

OBJECTIVE

To determine whether patients suffering postoperative nausea and vomiting (PONV) present a different serotonin release pattern from those who do not present this complication.

METHODS

Forty-eight consecutive women undergoing outpatient laparoscopic tubal ligation were enrolled in this prospective, cumulative case-control study. The study compared serotonin activity in 15 patients totally free of emetic symptoms (asymptomatic group) and, among patients with PONV (n = 33), those 15 who presented the most severe symptoms (PONV group). Patients were anesthetized with a regimen including sufentanil (0.1-0.3 microg x kg(-1)) plus thiopental (3-5 mg x kg(-1)) for induction and isoflurane (0.6-1%) in nitrous oxide (60%) for maintenance. Peripheral serotonin activity was assessed by measurement with high-performance liquid chromatography of serotonin's principal urinary metabolite: 5-hydroxyindoacetic acid (5-HIAA) corrected for urinary creatinine.

RESULTS

The preoperative and postoperative urinary 5-HIAA:creatinine ratios were 6.9 ng x microg(-1) (confidence interval; CI 95%, 2.7-11.0) and 5.9 ng x microg(-1) (CI 95%, 2.4-9.4) respectively in the asymptomatic group (P = 0.69), and were 5.1 ng x microg(-1) (CI 95%, 2.5-7.7) and 5.6 ng x micro(-1) (CI 95%, 3.4-7.7) respectively in the PONV group (P = 0.75). There was also no difference between groups in the variation of 5-HIAA:creatinine ratios from the preoperative to the postoperative period (P = 0.21).

CONCLUSIONS

PONV after laparoscopic tubal ligation are not associated with an increased urinary excretion of serotonin metabolites. Patients with severe PONV present a peripheral serotonin release comparable to asymptomatic patients.