The addition of antiemetics to the morphine solution in patient controlled analgesia syringes used by children after an appendicectomy does not reduce the incidence of postoperative nausea and vomiting.

Background: We studied the effect of intraoperative ondansetron 0.1 mg x kg(-1) or droperidol 0.01 mg.kg-1, followed by the same dose of the antiemetic agent added to the morphine solution during patient controlled analgesia (PCA) on the incidence of nausea and vomiting in children following an appendicectomy.

Methods: Sixty children, aged 5-13 years, were recruited and randomly allocated to receive no prophylactic antiemetic, the control group (group C), ondansetron (group O) or droperidol (group D). The PCA pump was programmed to deliver a bolus dose of 20 microg x kg(-1) of morphine.with a 5-min lockout period and a background infusion of 4 microg x kg(-1) x h(-1).

Results: Postoperatively, the three groups were compared for nausea, vomiting and sedation scores for 24 h. The incidence of postoperative nausea and vomiting was 33% for group C, 44% for group O and 41% for group D. There was no increase in sedation scores in the droperidol group.

Conclusions: We were unable to show any significant benefit from the prophylactic administration of ondansetron or droperidol to children using morphine PCA devices following appendicectomy in the doses we employed.