Continuous Wound Infiltration with Local Anesthetics in Adult Patients Undergoing Cardiac Surgery: a PRISMA-compliant Systematic Review and Meta-Analysis

Background Effective postoperative analgesia is critical to recovery after cardiac surgery. Continuous wound infiltration (CWI) with local anesthetics (LAs) has been proposed as an opioid-sparing adjunct, but its efficacy beyond pain control and its safety profile remain incompletely defined. Methods We conducted a PRISMA-compliant systematic review and meta-analysis of randomized controlled trials (RCTs) comparing CWI with control in adult cardiac surgery. PubMed, Embase, and Cochrane CENTRAL were searched from inception to August 30, 2025, and updated on April 2, 2026. Primary outcomes were postoperative Visual Analogue Scale (VAS) pain scores and cumulative morphine consumption. Secondary outcomes included mechanical ventilation duration, length of stay, mortality, complications, patient satisfaction, and adverse events. Risk of bias was assessed using the Cochrane RoB 2.0 tool, and certainty of evidence was evaluated using Grading of Recommendations Assessment, Development and Evaluation (GRADE). Results Twelve RCTs involving 2,117 patients were included. CWI significantly reduced VAS during mobilization at 24 h (MD=−0.93, 95% confidence interval [CI]: −1.53–−0.33, P = 0.002) and 48 h (MD=−0.80, 95% CI: −1.17–−0.44, P < 0.001), and decreased 48-hour morphine consumption (MD=−8.10 mg, 95% CI: −13.41–−2.79, P = 0.003). No significant effects were observed on VAS at rest, mechanical ventilation duration, ICU or hospital length of stay, mortality, or major cardiovascular, pulmonary, renal, gastrointestinal complications, or postoperative infections. Patient satisfaction was higher with CWI. Technical complications were uncommon, and no clinically significant LA toxicity was reported. Conclusions In adult cardiac surgery, CWI with LAs modestly improves analgesia during mobilization and reduces opioid requirements without clear improvement in major clinical outcomes or length of stay. CWI appears safe and feasible and may serve as an adjunct in multimodal, opioid-sparing analgesia strategies. Further adequately powered trials are warranted to define its comparative effectiveness within contemporary enhanced recovery after surgery (ERAS) pathways.