Evaluation of the efficiency of pharmacological antiemetic prophylaxis in different risk groups after general anaesthesia in the surgical population of Catalonia

Objective: To assess the efficiency of pharmacological antiemetic prophylaxis in patients subjected to surgery under general anaesthetic in different postoperative nausea and vomiting (NVPO) risk groups. Material and methods: A randomised, observational, prospective and multicentre cohort study was conducted. The study included 1239 patients from 26 hospitals who were subjected to elective surgery under general anaesthesia. The data collected included, demographic characteristics, the NVPO risk factors, anaesthetic technique, type of surgery, the duration, fluid therapy, antiemetic prophylaxis administered, and the incidence of NVPO in the first 24. h after surgery. A stratified analysis (low, moderate and high risk) was performed with the intention of evaluating the relationship between prophylaxis and NVPO using a logistic regression model adjusted for propensity score. The number of patients needed to treat (NNT) to prevent an NVPO episode was then calculated for each of the strata. Results: The incidence of NVPO in the low risk stratum was 21.6% without prophylaxis and 8.6% with prophylaxis, 31.3% compared to 17.7% in the moderate risk, and 46.5% compared to 32.7% in the high risk group. There was a significant protective effect in the three strata (odds ratio between treated and untreated patients) and in the NNT (95% CI) was 7 (5-11) in the low risk stratum, 7 (5-13) in that of the moderate risk, and 6 (4-16) in the high risk. Conclusions: The efficiency of pharmacological antiemetic prophylaxis in patients subjected to surgery under general anaesthesia was similar in all risk groups. Not providing antiemetic prophylaxis in low risk patients may not be justified due to the cost-effectiveness criteria. Future clinical guidelines to improve the quality of health care of patients operated on under general anaesthesia should consider the advantages of a universal NVPO prophylaxis. © 2011 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor.