Abstract
BACKGROUND: Fentanyl-based intravenous patient-controlled analgesia (IV PCA) is widely prescribed postoperatively. Basal infusion of fentanyl through IV PCA is associated with postoperative nausea and vomiting. However, the role of basal infusion in fentanyl-based IV PCA is not well-established. METHODS: This parallel-group, randomized controlled trial was conducted at a tertiary university medical center in the Republic of Korea from September 2022 to April 2023. Patient inclusion criteria were: age 20 to 65 years, intraperitoneal laparoscopic gynecologic surgery, patient-controlled analgesia (PCA) request from the surgical department, and written informed consent for PCA. Patients were allocated to basal infusion (BAS group) and bolus-only (BOL group) groups in a 1:1 ratio.A sum of 100 mL of analgesic mixture containing fentanyl 18.5 µg/kg, nefopam 120 mg, and ramosetron 0.3 mg was mixed in PCA pumps of both groups. For BAS group, basal infusion rate, bolus volume, and lock-out interval were 2 mL/hour, 1 mL, and 15 minutes, respectively. BOL group received no basal infusion; bolus volume and lock-out interval were 1 mL and 6 minutes, respectively.The primary outcome was postoperative nausea, measured using a self-response questionnaire 24 hours after operation and expressed as a 100-mm visual analog scale score. We also determined frequency of postoperative vomiting, quality of postoperative recovery (using Korean version of 15-item Quality of Recovery [QoR-15K] scale), and overall patient satisfaction with anesthetic service. RESULTS: A sum of 82 of the 88 patients enrolled were included. The visual analog scale score for postoperative nausea was 31.4 ± 31.3 mm; the condition was more severe in the BAS group than in the BOL group (95% confidence interval of difference: 2.1-28.9 mm, P = .024). The QoR-15K score, patient satisfaction, and rescue opioid doses used were similar across groups. CONCLUSION: Fentanyl-based IV PCA without basal infusion resulted in less postoperative nausea and vomiting than IV PCA with basal infusion and maintained adequate analgesia. Basal infusion can be omitted to reduce postoperative nausea using IV PCA by applying an appropriate lock-out interval. Further research comparing variable PCA settings is warranted.