Risk factors for postoperative nausea and vomiting after thoracoscopic pulmonary wedge resection: pitfalls of an increased fentanyl dose

Background Thoracoscopic pulmonary wedge resection (TPWR) is a surgical procedure that can maintain lung function and is less physically invasive to a patient. However, the risk factors for postoperative nausea and vomiting (PONV) following TPWR remain unknown. We aimed to evaluate multiple risk factors of PONV after TPWR and the impact of PONV on postoperative outcomes. Methods We retrospectively reviewed consecutive patients who underwent TPWR for malignant pulmonary tumors at our institution between October 2017 and March 2020. We assessed the differences in the clinical and perioperative parameters between the PONV and non-PONV groups. Results We reviewed 160 patients, of whom 27 (16.9%) had PONV. Sixteen (59.3%) patients with PONV required postoperative antiemetics. Failed mobilization was associated with PONV requiring postoperative antiemetics (P=0.048). In the multivariate analysis, increased fentanyl dose was an independent risk factor for PONV (P=0.022). Using the receiver operating characteristic curve, the optimal cut-off value for PONV was 3.58 µg/kg/hr (area under the curve =0.665; sensitivity =85.2%; specificity =53.4%; 95% confidence interval: 0.562-0.768; P=0.007). For example, in a case of a 50-kg patient who underwent a 70-min operation (our median operative time), the total dose of fentanyl within 208 µg was the cut-off value for preventing PONV. Conclusions An increased dose of fentanyl/kg/h was the strongest risk factor for PONV during TPWR. The optimal cut-off value for PONV was 3.58 µg/kg/hr. It is important to avoid the inadvertent administration of intraoperative fentanyl.