Opioid-free anesthesia versus opioid-based anesthesia in patients undergoing cardiovascular and thoracic surgery: a meta-analysis and systematic review

Background Despite their extensive clinical use, opioids are characterized by several side effects. These complications, coupled with the ongoing opioid epidemic, have favored the rise of opioid-free-anesthesia (OFA). Herein, we perform the first pairwise meta-analysis of clinical outcomes for OFA vs opioid-based anesthesia (OBA) in patients undergoing cardiovascular and thoracic surgery. Methods We comprehensively searched medical databases to identify studies comparing OFA and OBA in patients undergoing cardiovascular or thoracic surgery. Pairwise meta-analysis was performed using the Mantel-Haenszel method. Outcomes were pooled as risk ratios (RR) or standard mean differences (SMD) and their 95% confidence intervals (95% CI). Results Our pooled analysis included 919 patients (8 studies), of whom 488 underwent surgery with OBA and 431 with OFA. Among cardiovascular surgery patients, compared to OBA, OFA was associated with significantly reduced post-operative nausea and vomiting (RR, 0.57; P = .042), inotrope need (RR .84, P = .045), and non-invasive ventilation (RR, .54; P = .028). However, no differences were observed for 24hr pain score (SMD, -.35; P = .510) or 48hr morphine equivalent consumption (SMD, -1.09; P = .139). Among thoracic surgery patients, there was no difference between OFA and OBA for any of the explored outcomes, including post-operative nausea and vomiting (RR, 0.41; P = .025). Conclusion Through the first pooled analysis of OBA vs OFA in a cardiothoracic-exclusive cohort, we found no significant difference in any of the pooled outcomes for thoracic surgery patients. Although limited to 2 cardiovascular surgery studies, OFA was associated with significantly reduced postoperative nausea and vomiting, inotrope need, and non-invasive ventilation in these patients. With growing use of OFA in invasive operations, further studies are needed to assess their efficacy and safety in cardiothoracic patients.