Effect of Body Mass Index on Postoperative Nausea and Vomiting: Propensity Analysis

Figure 1. Flow chart.

Figure 2. ORs for development of PONV in underweight, overweight, and obese patients. UA, unadjusted; FA, fully adjusted; FS, all covariates + propensity score adjusted; BE, backward elimination, CI, confidence interval; OR, odds ratio. Covariates for overweight BE: age, female, operation duration, American Society of Anesthesiologists physical status, use of N2O, patient-controlled analgesia, smoking, use of antiemetics, neostigmine, proton-pump inhibitors, or antibiotics, laparoscopic surgery, and transfusion. Covariates for obese BE: age, female, operation duration, use of N2O, patient-controlled analgesia, smoking, use of antiemetics, neostigmine, or proton-pump inhibitors, gastroesophageal reflux disease, and Levin tube.