Background and Goal of Study: Apfel score is widely used for predicting postoperative nausea and vomiting (PONV). However gynecological major surgery patients are already scored more than Apfel score of 2 (female and postoperative opioid use). In these PONV high risk patient population, more effective prediction method is required. Japanese traditional Kampo medicine has a unique methodology of human body constitution classification. Kampo medicine specific concept, “Water stagnation” is considered as a status of abnormal fluid distribution state with the body feature tendency of accumulating unnecessary body fluid and blunting fluid elimination function, and has been reported to be a high risk for nausea and vomiting. The purpose of this study is to clarify whether water stagnation score (WSS), which is calculated using a self-assessed questionnaire (Table 1), is useful to predict PONV for the gynecological patients.
 
Materials and Methods: With IRB approval and written informed consent, WSS was preoperatively assessed. Inclusion criteria were 1) elective gynecological surgery, 2) aged 20 to 50 years, and 3) scheduled expected procedure time > 2 hours. Exclusion criteria were 1)ASA-PS 3 or more, 2) body mass index 35 or more, 3) pregnant and lactating women, 4) regular use of any Kampo medicine, and 5) use of steroids, immunosuppressive or chemotherapy medicines. Intraoperative fentanyl total dose was intended to be 8-12 mcg/kg. Postoperatively patient-controlled fentanyl infusion pump was used. PONV incidence during first 6 hours after general anesthesia was assessed, and patients were divided into PONV group or control group (no PONV). Patient demographics, intraoperative factors and WSS were compared between groups. The unpaired t-test or Mann-Whitney U-test was applied.

Results and Discussion: Eighty three patients were studied, and 53 patients developed PONV in the first 6 hour postoperatively and 30 did not develop PONV. WSS was 7.3±7.8 in control group, and 10.4±7.0 in PONV group (p=0.073). Incidence of water stagnation state (WSS≥13), was 3.4% in control group and 20.1% in PONV group (p=0.01). In ROC analysis, sensitivity was 0.86 and specificity was 0.32, and area under curve was 0.68 with cut off WSS value of 13.

Conclusion: As WSS can classify the human physical constitution more precisely than Apfel score, WSS is a useful predictor of PONV for gynecological surgical patients.

Prediction of postoperative nausea vomiting, using Japanese traditional Kampo medicine, “Water Stagnation Score”