[Postoperative nausea and vomiting. Identification of patients with risk factors for PONV]

This review discusses the clinical relevance of risk stratification to determine measures to prevent postoperative nausea and vomiting. The key question is whether PU&E is a problem related only to a small group of risk patients and whether risk stratification is a reasonable approach to deal with this problem. The application of risk scores to predict PU&E has been strongly advocated in the past years. These tools suggest that PU&E is mainly a problem of a small and well defined group of patients that can be identified and clearly separated from patients with no risk for PU&E. The need for applying these risk scores was based on the assumption that efficiency of antiemetic intervention mainly depends on the baseline risk for PU&E and that these are only justified at an increased risk (e.g. PU&E-risk > 60 %) where the number needed to treat is about 5 or lower. PU&E, on the other hand, are distressing and annoying symptoms for the patient. PU&E is a limiting factor for any approach to speed postoperative recovery and thus incompatible with so called fast-track rehabilitation programs. Thus, PU&E is relevant not only for high-risk patients but also for the great majority of patients with an intermediate risk for PU&E. The latter group, e.g. patients with a predicted risk to suffer from PU&E between 20 and 60 %, account for more than 80 % of all patients undergoing risk evaluation. Considering the high impact of PU&E for the individual patient, the small incidence of patients where the occurrence of PU&E can be ruled out with appropriate high probability, and finally the availability of several effective antiemetic measures all with a marked low incidence of side-effects, the authors of this review advocate a liberal policy for prophylactic administration of antiemetics. Prophylaxis against PU&E should be as self-evident as measures to limit postoperative pain. Omitting antiemetic prevention should only be considered if the estimated risk for PU&E is extremely low. All other patients in whom PU&E cannot be ruled out with high confidence should receive routine antiemetic prophylaxis.