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Postoperative nausea and vomiting (PONV) is one of the most important problems for patients after surgery. Multiple scores have been developed to predict the risk of PONV in adults during the last decade. On the base of these scores the incidence of PONV could be reduced by adequate prophylaxis. In 2004 Eberhart et al. presented a simplified risk score to predict postoperative vomiting in children in a wide range of surgery (POVOC-Score). The aim of our study is to prove the predictive power of the POVOC-Score, which is based on following risk factors: age >= 3 years, duration of operation >= 30 minutes, and history of previous PONV and/or motion sickness in the patient, his parents or siblings. Strabism surgery the fourth risk factor of the POVOC-Score is not performed in our institution.
524 children undergoing a variety of surgical procedures under general anaesthesia were included. Preoperatively, the POVOC-Score was performed and the patients were divided in four groups according to the number of existing risk factors. No intravenous anaesthesia or any antiemetic prophylaxis was applied. Postoperatively, the patients were observed for 24 hours. Both, the patients and the nursing staff were asked whether postoperative vomiting (PV) or PONV was present. Furthermore practicability, discrimination (by means of the area under a receiver operating characteristics curve) and calibration properties (by means of a weighted linear regression between the predicted and the actual incidences of PONV) were estimated.
The cumulative incidence of PV was 20,2% within 24 hours, the PV-rate in the four groups (0 – 3 risk factors) was 3%, 12%, 28%, and 42% respectively. The AUC under the ROC-curve was 0,72 in our population as well as in the evaluation-group (95% confidence interval 0,68-0,76). The AUC under the ROC-curve was 0,76 when using “postoperative therapy with opioids” as the fourth risk factor. There was a good correlation of the predicted incidences of the score with the actual incidences observed.
These results should be validated in other institutions, but we recommend the use of the POVOC-Score to allow goal-directed use of antiemetic measures in patients with moderate to high risk of PV. In patients with more than one risk factor, volatile anaesthetics should be avoided, patients with 3 risk factors should receive dexamethason after anaesthesia has started. Patients with 4 risk factors should receive a 5-HT3-antagonist additionally.