Opioid-free anesthesia for minimally invasive abdominal surgery: a systematic review, meta-analysis, and trial sequential analysis

Purpose Opioid anesthesia is commonly employed in minimally invasive surgeries but is associated with adverse effects, including postoperative nausea and vomiting (PONV). Opioid-free anesthesia aims to mitigate these issues. We conducted a systematic review, meta-analysis, and trial sequential analysis (TSA) comparing opioid and opioid-free anesthesia in minimally invasive abdominal surgeries. Methods We searched the Cochrane Central Register of Controlled Trials, MEDLINE, and Embase for randomized controlled trials (RCTs) comparing these approaches. Our primary outcomes were adverse effects (PONV, bradycardia), while secondary outcomes were pain, opioid consumption, and postanesthesia care unit (PACU) length of stay (LOS). We performed a TSA to investigate the conclusiveness of the results. Results We included 26 RCTs encompassing 2,025 patients, with 1,009 (49%) in the opioid-free anesthesia group. Opioid-free anesthesia reduced PONV significantly (risk ratio, 0.55; 95% confidence interval [CI], 0.40 to 0.74; P