Local anaesthetic wound infiltration for postcaesarean section analgesia: A systematic review and meta-analysis

BACKGROUNDWound infiltration with local anaesthetics has been investigated as a potentially useful method for providing analgesia after caesarean delivery, but the literature is inconclusive.OBJECTIVEThe objective is to assess the efficacy of local anaesthetic wound infiltration in reducing pain scores and opioid consumption in women undergoing caesarean delivery.DESIGNSystematic review of randomised controlled trials with meta-analyses.DATA SOURCESMEDLINE, EMBASE, CINAHL, and Cochrane Central Register of Controlled trials (CENTRAL) until December 2015.ELIGIBILITY CRITERIARandomised controlled trials that assessed the efficacy of local anaesthetic wound infiltration using an infusion or single injection technique for postcaesarean section analgesia.RESULTSA total of 21 studies were included in the final analysis (11 studies using an infusion technique and 10 studies using single infiltration). Local anaesthetic wound infiltration significantly decreased opioid consumption at 24h [mean difference -9.69mg morphine equivalents, 95% confidence interval (CI), -14.85 to -4.52] and pain scores after 24h at rest (mean difference -0.36, 95% CI, -0.58 to -0.14) and on movement (mean difference -0.61, 95% CI, -1.19 to -0.03). Subgroup analysis did not suggest a difference in primary outcomes between infusions and single infiltration. Opioid consumption was reduced in patients who did not receive intrathecal morphine but not in those who received intrathecal morphine, although there were very little data in patients receiving intrathecal morphine. Pain scores at rest and on movement at 24h were reduced with catheter placement below the fascia but not above the fascia. There were no statistically significant reductions in nausea, vomiting or pruritus with local anaesthetic infiltration.CONCLUSIONLocal anaesthetic wound infiltration reduces postoperative opioid consumption but had minimal effect on pain scores and did not reduce opioid-related side-effects in women who had undergone delivery by caesarean section. The review is limited by a paucity of studies using intrathecal morphine and by the indirect comparisons performed for subgroup analyses.