Postoperative nausea and vomiting in cardiac surgery

Abstract

Editor, Recently published editorials [1,2] described recurrent interest in droperidol for postoperative nausea and vomiting (PONV) prophylaxis and treatment. In 2004, we presented the results of a double-blind prospective randomized trial examining the incidence of PONV in cardiac surgery, its relation to cardiopulmonary bypass (CPB) duration, and the efficacy of different antiemetic drugs for PONV prevention [3]. In a prospective fashion, we studied 142 adult patients with left ventricle ejection fraction of more than 45% undergoing coronary artery bypass grafting (CABG) with CPB. The induction and maintenance of anaesthesia were standardized. Postoperative analgesia was provided with morphine intravenously (i.v.) as needed. The patients had no previous history of PONV; all risk factors for PONV were similar among groups. The patients were randomly allocated to receive droperidol 1.25 mg (group I, n = 27), thiethylperazine 6.5 mg (group II, n = 33), ondansetron 4 mg (group III, n = 34), or placebo (group IV, n = 48) 30 min before the end of the procedure. The duration of CPB and the number of PONV episodes during the first 12 h in the ICU were recorded. Metoclopramide was chosen as a rescue medication to treat PONV episodes. The results were evaluated by correlation coefficient (r) and χ2 test (P). The duration of CPB in individual study groups (mean ± SD: I, 76 ± 16; II, 74 ± 13, III, 74 ± 17; and IV, 73 ± 18 min, respectively) had no influence on the incidence of PONV in each group (r = −0.080), and all the groups together (r = −0.081). The incidence of PONV after pharmacological prevention (18.5, 18.0, 18.0%) was insignificantly (P > 0.05) lower than that in placebo group (27.1%). The number of patients in groups I, II, and III with more than one PONV episode (3.7, 9.0, 2.9%) was not reduced significantly (P > 0.05) compared with placebo (10.4%). The incidence of PONV in CABG patients was comparable to other types of surgery and did not correlate with the CPB duration. The pharmacological prophylaxis did not significantly decrease incidence and the number of PONV episodes. Our results suggest that droperidol was as effective as other antiemetic agents that do not carry the black box warning. Droperidol appeared as well tolerated and as effective as other tested agents in our study. However, it could be easily substituted by other agents, which are associated with less cardiovascular/neurologic/psychiatric adverse effects. Although the rationale to keep the black box on droperidol may be subject to ongoing debate, it seems that there are other options available that serve high-risk cardiac population as well as droperidol.