Postoperative nausea and vomiting in children using patient-controlled analgesia: the effect of prophylactic intravenous dixyrazine

Background: Although patient-controlled analgesia (PCA) with morphine provi des a high degree of satisfactory postoperative analgesia in children, it i s often associated with a high incidence of postoperative nausea and vomiti ng (PONV). Our aim in this study was to evaluate the prophylactic effect of dixyrazine, a phenothiazine with proven anti-emetic properties. Methods: The incidence of nausea and vomiting was studied in 60 children us ing PCA after major surgery. The patients were randomised to receive either dixyrazine 0.25 mg kg(-1) or placebo on the induction of anaesthesia in a double-blind, placebo-controlled design. The anaesthetic technique was stan dardised. The PCA pump was programmed to deliver bolus doses of morphine of 20 mu g kg(-1) with a continuous background infusion of 8-10 mu g kg(-1) h (-1). Nausea, vomiting, sedation and pain scopes were noted every 3 h for a period of 24 h. Results: The morphine consumption of morphine was the same in both groups. During the stay in the recovery room the incidence of vomiting was 3% in th e dixyrazine group compared to 30% in the placebo group (P<0.05). On the wa rd, 57% versus 83% of the children vomited (P<0.05). Rescue antiemetics wer e significantly lower, 30%, in the dixyrazine group compared to 60% in the placebo group (P<0.05). Higher sedation scores were recorded for the dixyra zine group in the recovery room. No other adverse effects were found. Conclusion: A significant number of children using PCA with morphine after major surgery experience PONV. Although prophylactic dixyrazine reduces the incidence and severity of vomiting, the incidence still remains high.