Continuous wound infiltration of bupivacaine at two different anatomical planes for caesarean analgesia – A randomised clinical trial

Background and Aims: Continuous wound infiltration of local anaesthetics provide postoperative analgesia by peripheral nociceptors blockade. The placement of wound infiltration catheter in the optimal anatomical plane of surgical wound may play a significant role in reducing postoperative pain depends on the surgical procedure. We hypothesised that preperitoneal infusion of local anaesthetics will reduce the postoperative opioid consumption as compared to subcutaneous infusion following cesarean section. Methods: This was a randomised, double-blinded clinical trial. Fifty-two pregnant women who underwent lower segment caesarean section by Pfannensteil incision, under spinal anaesthesia, were randomised to group 'subcutaneous' and group 'preperitoneal'. A wound infiltration catheter was placed in the subcutaneous or preperitoneal plane, depending on their randomisation at the end of the surgery. Bupivacaine of 0.25% at 5 mL/h was infused for the next 48 h. Pain was assessed using numerical rating scale at 1, 2, 3, 4, 5, 6, 12, 24, 36 and 48 h after surgery. Cumulative postoperative consumption and adverse effects of morphine and complications of the procedure were looked for. Results: Cumulative 48-h morphine consumption showed no statistical significance between the preperitoneal group (15.96 ± 7.69 mg) and subcutaneous group (21.26 ± 11.03 mg); P = 0.058. Pain score was comparable. Independent T-test and Mann–Whitney test were the statistical tests used for continuous and categorical data, respectively. Conclusion: Postoperative cumulative morphine consumption and pain scores are comparable when bupivacaine is infused continuously through wound infiltration catheter either in the preperitoneal or subcutaneous layer following Caesarean delivery.