Comparative Analgesic Efficacies of Ropivacaine and Bupivacaine for Postoperative Rectus Sheath Block in Paediatric Abdominal Surgery: A Meta-Analysis of Randomized Controlled Trial and Retrospective Cohort Studies

Background. The optimal dose and concentration of analgesic efficacy of ropivacaine (RPV) and bupivacaine (BPV) for postoperative pain relief in paediatric abdominal surgery patients is still unclear. Therefore, this meta-analysis compared the efficacy of these analgesics, their administered modes (ultrasound-guided RSB versus LAI) for postoperative pain relief, and side effects. Methods. Three databases, PubMed, Embase, and Cochrane Database of Systematic Reviews, were exhaustively searched with predefined keywords. Eight randomized clinical trials and retrospective studies were selected. Analgesic effect, postoperative pain score, level of side effect, applied dose, and concentration of drug were analysed. Results. Drug dose ranged from 0.5-2.5 mL/kg of 0.2 to 0.5% concentrations. Male participant for RSB and LAI treatment groups varied from 40-62% and 25-83%, respectively. Mean age of RSB and LAI groups ranged from 3.8-11.65 years and 4.3-11.27 years, respectively. Our meta-analysis revealed that RSB could reduce total opioid use postoperatively (WMD = -0.02, 95% CI: -0.02, -0.02), with I2 value of 15%. We found that the RPV (0.25%, 2.5 ml/kg) was optimal in suppressing the pain. Its lower concentration (0.2%) was ineffective, whereas higher one (0.375%) seems to increase risk of systemic toxicity. Similarly, BPV (0.25%, 2.5 mg/kg) efficaciously reduced the pain score, while its lower concentration was ineffective. The combined postoperative pain score in the RPV-treated group was found to be significantly reduced (p<0.01) with I2 value of 85% indicating high heterogeneity. Conclusion. Both RPV and BPV were significantly effective in reducing postoperative pain score. It appears that RSB could be a preferred choice to deliver analgesia, due to reduced opiate dose requirement and improved clinical safety without significant postoperative adverse events.