Dynamic predictive model for postoperative nausea and vomiting for intravenous fentanyl patient-controlled analgesia

Abstract

Postoperative nausea and vomiting is the most common side-effect of opioid-based intravenous patient-controlled analgesia. Apfel's simplified risk score is popular but it has some limitations. We developed and validated a dynamic predictive model for nausea or vomiting up to 48 postoperative hours, available as an online web application. Fentanyl was used by 22,144 adult patients for analgesia after non-cardiac surgery under general anaesthesia: we randomly divided them into development (80%) and validation (20%) cohorts, repeated 100 times. We used linear discriminant analysis to select variables for multivariate logistic regression. The incidences of postoperative nausea or vomiting were: 0–48 h, 5691/22,144 (26%); 0–6 h, 2749/22,144 (12%); 6–12 h, 2687/22,144 (12%); 12–18 h, 2624/22,144 (12%); 18–24 h, 1884/22,144 (9%); and 24–48 h, 1082/22,144 (5%). The median (95%CI) area under the receiver operating characteristic curve was 0.72 (0.71–0.73) up to 48 postoperative hours compared with 0.65 (0.64–0.66) for the Apfel model, p < 0.001. The equivalent areas for 0–6 h, 6–12 h, 12–18 h, 18–24 h and 24–48 h were: 0.70 (0.69–0.72); 0.71 (0.69–0.73); 0.69 (0.68–0.71); 0.70 (0.67–0.72); and 0.69 (0.66–0.71), respectively. Our web application allows clinicians to calculate incidences of nausea and vomiting in patients receiving intravenous fentanyl for patient-controlled analgesia.