Comparison of two instruments for assessing risk of postoperative nausea and vomiting

Abstract

Two instruments for assessing patients' risk of postoperative nausea and vomiting (PONV) were compared. The existing protocol (protocol 1) assessed PONV risk using 16 weighted risk factors and was used for both adults and pediatric patients. The new protocol (protocol 2) included a form for adults and a pediatric-specific form. The form for adults utilized the simplified risk score, calculated using a validated, nonweighted, 4-point scale, and categorized patients' risk of PONV as low, moderate, or high. The form for pediatric patients used a 7-point, non-weighted scale and categorized patients' risk of PONV as moderate or high. A list was generated of all patients who had surgery during August 2005, for whom protocol 1 was used, and during April 2006, for whom protocol 2 was used. Fifty patients from each time period were randomly selected for data analysis. Data collected included the percentage of the form completed, the development of PONV, the number of PONV risk factors, patient demographics, and the appropriateness of prophylaxis. The mean +/- S.D. number of PONV risk factors was significantly lower in the group treated according to protocol 2 ( p = 0.001), but fewer patients in this group were categorized as low or moderate risk and more patients were identified as high risk (p < 0.001). More patients assessed by protocol 2 received fewer interventions than recommended (p < 0.001); however, the frequency of PONV did not significantly differ between groups. Implementation of a validated and simplified PONV risk-assessment tool appeared to improve form completion rates and appropriate risk assessment; however, the rates of PONV remained similar and fewer patients received appropriate prophylaxis compared with patients assessed by the existing risk-assessment tool.