A Single Prophylactic Dose of Ondansetron Given at Cessation of Postoperative Propofol Sedation Decreases Postoperative Nausea and Vomiting in Cardiac Surgery Patients: A Randomized Controlled Trial

BACKGROUND: Postoperative nausea and vomiting (PONV) is a common occurrence after cardiac surgery. However, in contrast to other surgical populations, routine PONV prophylaxis is not a standard of care in cardiac surgery. We hypothesized that routine administration of a single prophylactic dose of ondansetron (4 mg) at the time of stopping postoperative propofol sedation before extubation in the cardiac surgery intensive care unit would decrease the incidence of PONV. METHODS: With institutional human ethics board approval and written informed consent, we conducted a randomized controlled trial in patients >= 19 years of age with no history of PONV undergoing elective or urgent cardiac surgery procedures requiring cardiopulmonary bypass. The primary outcome was the incidence of PONV in the first 24 hours postextubation, compared by the chi(2)test. Secondary outcomes included the incidence and times to first dose of rescue antiemetic treatment administration, the incidence of headaches, and the incidence of ventricular arrhythmias. RESULTS: PONV within the first 24 hours postextubation occurred in 33 of 77 patients (43%) in the ondansetron group versus 50 of 82 patients (61%) in the placebo group (relative risk, 0.70 [95% confidence interval {CI}, 0.51-0.95]; absolute risk difference, -18% [95% CI, -33 to -2]; number needed to treat, 5.5 [95% CI, 3.0-58.4]; chi(2)test,P= .022). Kaplan-Meier "survival" analysis of the times to first rescue antiemetic treatment administration over 24 hours indicated that patients in the ondansetron group fared better than those in the placebo group (log-rank [Mantel-Cox] test;P= .028). Overall, 32 of 77 patients (42%) in the ondansetron group received rescue antiemetic treatment over the first 24 hours postextubation versus 47 of 82 patients (57%) in the placebo group (relative risk, 0.73 [95% CI, 0.52-1.00]; absolute risk difference, -16% [95% CI, -31 to 1]);P= .047. There were no significant differences between the groups in the incidence of postoperative headache (ondansetron group, 5 of 77 patients [6%] versus placebo group, 4 of 82 patients [5%]; Fisher exact test;P= .740) or ventricular arrhythmias (ondansetron group, 2 of 77 patients [3%] versus placebo group, 4 of 82 patients [5%];P= .68). CONCLUSIONS: These findings support the routine administration of ondansetron prophylaxis at the time of discontinuation of postoperative propofol sedation before extubation in patients following cardiac surgery. Further research is warranted to optimize PONV prophylaxis in cardiac surgery patients.