Prophylactic ondansetron in prevention of postoperative nausea and vomiting following pediatric strabismus surgery - A dose-response study

Background: This study evaluated the antiemetic effectiveness, dose-respons e, and clinical usefulness of prophylactic ondansetron in the prevention of postoperative nausea and vomiting (PONV) in children undergoing strabismus repair. Method: The authors observed 180 children, American Society of Anesthesiolo gists physical status I or II, 2-12 yr of age, who were undergoing strabism us repair. After induction of anesthesia with halothane and nitrous oxide i n oxygen or intravenous thiopental, children received either placebo (salin e) or intravenous ondansetron in doses of 25, 50, 75, 100, and 150 mu g/kg (n = 30). The trachea was intubated and ventilation was controlled. Periope rative analgesic and fluid requirements were standardized. Episodes of naus ea and vomiting were recorded for the first 24 h postoperatively. Data such as nonsurrogate (parental satisfaction scores and duration of postanesthes ia care unit stay) and therapeutic (numbers needed to prevent and harm) out come measures were collected. Results: The incidences of PONV in the placebo and 25-, 50-, 75-, 100-, and 150-mu g/kg ondansetron groups were 83, 77, 47, 30, 30, and 27%, respectiv ely. The incidence was less in the 75- (P = 0.002), 100- (P = 0.002), and 1 50-mu g/kg (P < 0.001) ondansetron groups compared with placebo. Duration o f stay in the postanesthesia care unit was shorter in the 75-, 100-, and 15 0-mu g/kg ondansetron groups (P < 0.002) compared with the placebo group. P arental assessment scores for the child's perioperative experience and the positive number needed to prevent PONV were also better and favorable in th e 75-, 100-, and 150-mu g/kg ondansetron groups compared with the placebo g roup. The incidence (P > 0.99) and severity (P = 0.63) of PONV were similar in the 75- and 150-mu g/kg ondansetron groups. Surrogate, nonsurrogate, an d therapeutic outcome measures revealed that 75 mu g/kg ondansetron provide d the same benefits as did 100 and 150 mu g/kg. Conclusion: The routine prophylactic use of ondansetron at a dose of 75 mu g/kg is as effective as 150 mu g/kg in preventing PONV and improving the "t rue" outcome measures after strabismus repair in children.