Single-injection serratus anterior plane block for cardiothoracic surgery via thoracotomy in children: a systematic review and meta-analysis of randomised controlled trials.

Background: Serratus anterior plane block (SAPB) has gained popularity in cardiothoracic surgery due to its feasibility and simplicity. However, the efficacy of ultrasound-guided single-injection SAPB in the paediatric population has not been well evaluated, as only a few studies with small sample sizes are available.

Methods: We searched PubMed, Embase (Ovid), Cochrane Central Register of Controlled Trials, Wanfang databases and China National Knowledge Infrastructure from their inception to 31 September 2022 for randomised comparative clinical trials that compared single-injection SAPB with systemic analgesia or different forms of regional analgesia in children. The primary outcomes included postoperative opioid consumption and pain scores within 24 hours. The secondary outcomes included postoperative adverse events, the need for rescue analgesia and the time from the end of surgery to endotracheal tube removal.

Results: Five randomised controlled trials with 418 children meeting the inclusion criteria were included. SAPB markedly reduced postoperative opioid consumption up to 24 hours compared with controls (mean difference (MD): -0.29 mg/kg, 95% CI -0.38 to -0.20, =67%]. The postoperative pain scores were reduced compared with controls: 1 hour (MD -0.6, 95% CI -1.17 to -0.04, =92%), 4-6 hours (MD -1.16, 95% CI -1.87 to -0.45, =90%) and 12 hours (MD -0.71, 95% CI -1.35 to -0.08, =86%). The incidence of postoperative nausea and vomiting was comparable between SAPB and controls. One trial suggested that the analgesic effect of SAPB was comparable to that of ICNB (intercostal nerve block).

Conclusion: Single-injection SAPB is associated with a reduction in opioid consumption and pain intensity after cardiothoracic surgery via thoracotomy in children. Due to the high heterogeneity, the Grading of Recommendations Assessment, Development and Evaluation scores were low. Clinical trials with rigorous methodological approaches as well as safety endpoints are needed to confirm these preliminary findings.

Prospero Registration Number: CRD42021241691.