[Prophylaxis of postoperative nausea and vomiting (PONV) in children undergoing strabismus surgery. Sevoflurane/N2O plus dimenhydrinate vs.propofol/remifentanil plus dimenhydrinate].

BACKGROUND AND STUDY GOALS: Strabismus surgery in children is frequently associated with a very high incidence of postoperative nausea and vomiting (PONV). In this study we investigated, whether TIVA is superior to inhalation anaesthesia concerning PONV when a prophylaxis using dimenhydrinate (diphenhydramine chlorotheophyllate) is administered in both groups.

METHODS

110 patients (3-10 years) were prospectively and randomly allocated to one of the following groups: Group TD (TIVA/dimenhydrinate; n= 55): anaesthesia was induced and maintained using remifentanil and propofol in common clinical dosages. Patients were ventilated with 30% O(2) in air. Group VD (Volatile/ dimenhydrinate; n= 55): anaesthesia was induced and maintained with sevoflurane in common clinical concentrations together with N(2)O in 30% O(2). All patients received dimenhydrinate 1 mg.kg(-1) i.v. after induction. PONV was recorded within the first 24 h postoperatively. The chi-square test and a multivariate analysis were used for statistical analysis.

RESULTS

52 patients of group TD and 54 of group VD were analysed. There was a trend in the incidence of postoperative nausea (PN): group TD 17%, 95% CI: 8-30%) compared to group VD 31%, 95% CI: 20-46%), p = 0.09. No difference was seen for PV and PONV: 21% (95% CI: 11-35%) in group TD vs. 35% (95% CI: 23-49%) in group VD, p = 0.109. These non-significant results can be easily attributed to the lack of power about 30%) of this study. According to the results of the multivariate analysis volatile anaesthesia was identified as an independent risk factor for PONV (OR: 2.92, 95% CI: 1.02-8.36). Other variables that were found to be an independent risk factor included history of PONV (OR: 8.19, 95% CI: 1.84-36.43), surgery lasting longer than 30 min (OR: 5.89, 95% CI: 1.82-19.82) and "Faden-operations" (retroequatorial myopexy) (OR: 5.48, 95% CI: 1.74-17.21).

CONCLUSIONS

TD only showed a trend to lower PN incidences and no differences as for PV and PONV incidences, most likely due to a lack of power of this study. However, according to the results of the multivariate analysis, inhalation anaesthesia was shown to be an independent risk factor for PONV, as were history of PONV, surgery >30 min and "Faden-operations".