Comparison of Opioid-Free Versions of Total Intravenous Anesthesia and Inhalational Anesthesia in Bariatric Surgery: A Randomized Controlled Trial

Background Opioid-free anesthesia (OFA) is increasingly used in bariatric surgery to prevent opioid-related adverse effects. Although both propofol-based total intravenous anesthesia (TIVA) and volatile anesthesia with sevoflurane are compatible with OFA protocols, their relative opioid-free effectiveness is unclear. Methods In this single-center randomized controlled trial, 256 patients undergoing laparoscopic sleeve gastrectomy received either OFA with TIVA (propofol via Schnider TCI model) or OFA with sevoflurane. Both groups received identical nonopioid adjuncts (lidocaine, ketamine, dexmedetomidine). The primary outcome was the incidence of postoperative nausea and vomiting (PONV) within 24 h. Secondary outcomes included pain scores, opioid consumption, hemodynamic stability, and emergence characteristics. Results The primary endpoint, postoperative nausea and/or vomiting within 24 h, did not differ between groups and occurred in 80/123 patients (65.0%) in the Sevo group and 86/133 patients (64.7%) in the TIVA group (difference 0.4% points, 95% CI − 11.2 to 11.9; p = 1.000). Rates of postoperative nausea (65.0% vs. 63.2%; p = 0.855) and vomiting (25.2% vs. 26.3%; p = 0.952) were likewise similar. Postoperative pain scores and 24-hour opioid consumption were low and comparable. Hemodynamic events and rescue analgesic requirements were similar. However, prolonged emergence (> 10 min) was more frequent in the TIVA group than in the Sevo group (22.6% vs. 12.2%; difference 10.4% points, 95% CI 1.0 to 19.5; p = 0.044). Conclusion Opioid-free total intravenous anesthesia or opioid-free inhalational anesthesia with sevoflurane provide effective and safe anesthesia for bariatric surgery, with comparable pain control and opioid-sparing effects. High PONV incidence persists despite OFA, underscoring the need for enhanced prophylaxis. Emergence was modestly slower with TIVA, which may be related to known limitations of conventional target-controlled infusion models in patients with severe obesity and warrants further study. Trial Registration The study was registered at ClinicalTrials.gov (NCT06390046). The record was first posted on April 29, 2024 and the first participant was enrolled on April 30, 2024.