Postoperative Analgesia by a Transversus Abdominis Plane Block Using Different Concentrations of Ropivacaine for Abdominal Surgery: A Meta-Analysis

Transversus abdominis plane block (TAPB) has been proven to be an effective means of postoperative anesthesia, but the optimum effective concentration of ropivacaine warrants further research. This study aimed to identify the optimal ropivacaine concentration of TAPB using a meta-analysis. This study consisted of a meta-analysis of randomized controlled trials (RCTs). We searched online databases, including PubMed, Embase, the Cochrane Database of Systematic Reviews, and Web of Science. RCTs investigating the 24-hour postoperative opioid consumption and the rest and dynamic pain scores 2, 12, and 24 hours after surgery were included in this analysis. We also assessed opioid-related side-effects and patient satisfaction 24 hours after surgery. Nineteen RCTs (1217 patients) were included in this meta-analysis, which showed that only TAPB with 0.375% and 0.5% ropivacaine was able to reduce opioid consumption 24 hours after surgery by weighted mean differences of -6.55 and -4.44 mg (morphine IV equivalents), respectively (P