Analgesic efficacy of locoregional anesthesia techniques in cardiac surgery: a systematic review and network meta-analysis of randomized trials

BACKGROUND: Postoperative pain following cardiac surgery remains a clinical challenge. Despite opioids remaining central to perioperative analgesia, their adverse-effect burden drives the search for effective locoregional analgesic (LRA) alternatives; yet guideline recommendations remain constrained by the lack of high-quality comparative data among LRA techniques. METHODS: This systematic review and network meta-analysis evaluated the analgesic efficacy of relevant LRA techniques in adult patients undergoing cardiac surgery. Primary outcomes were opioid consumption, pain scores, and time to first rescue analgesia within 24 hours postoperatively. Secondary outcomes included intensive care unit (ICU) and hospital length of stay (LOS), block-related complications, and side effects. PubMed, Embase, and CENTRAL were searched up to June 30, 2025. A Bayesian random-effects network meta-analysis was performed. Certainty of evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluation. RESULTS: 133 randomized trials (9816 patients) were included. Compared with control, three LRA techniques reduced 24-hour opioid consumption (MME, mean difference (95% credible interval)): intrathecal opioids (IT) -14.8 (-20.7; -9.2), erector spinae plane block (ESPB) -9.7 (-14.8; -4.9), and parasternal intercostal plane block (PIPB) -6.3 (10.5; -2.3). IT produced the largest and consistent pain score reductions (-1.2 cm (-3.3; -0.7) on the visual analog scale at 24 hours). No technique prolonged time to first rescue analgesia. ESPB -8.3 hours (-13.7; -2.8), PIPB -7.2 hours (-12.2; -2.3), and TEA -11.8 hours (-20.2; -3.0) reduced ICU LOS, while only TEA reduced hospital LOS by 1.2 days (-1.7; -0.6). No major block-related complications were reported. CONCLUSIONS: IT demonstrated the largest reductions in opioid consumption and pain scores in the first 24 hours. ESPB and PIPB represent promising alternatives when neuraxial techniques are contraindicated, though effect sizes were smaller, often below thresholds of clinical relevance. Substantial interstudy heterogeneity emphasizes the need for rigorous, high-quality trials to standardize LRA strategies in cardiac surgery and to better define their impact on recovery and safety endpoints. PROSPERO REGISTRATION NUMBER: CRD42021261282.