Lidocaine vs. tramadol vs. placebo wound infiltration for post-cesarean section pain relief: a randomized controlled trial.

Abstract

In low-income settings, postoperative pain relief could be challenging as a high patient/nurse ratio limits pain assessment and adequate analgesics administration. The multi-center prospective double-blinded parallel randomized controlled trial was done to compare lidocaine, tramadol, and placebo (saline) intraoperative wound infiltration to relieve post-cesarean section wound pain during the first 24h. Ninety-nine cases were equally randomized into three groups, each containing 33 pregnant women undergoing cesarean section under general anesthesia. During operation, the wound was infiltrated subcutaneously with 20mL of 2% lidocaine solution in the first group, 2mg/kg tramadol in the second group, and saline in the third group. The primary outcome was to assess the postoperative pain at 2, 4, 6, 12, and 24h by the Yes-No-Don't Know (YNDK) Scale, while the secondary outcome was to assess the need for further postoperative analgesia. Wound infiltration with lidocaine or tramadol was effective in pain relief, and both were superior to placebo. Wound infiltration with tramadol was superior to lidocaine in pain relief at 2h and up to 24h. Wound infiltration with tramadol has a more prolonged pain relief effect than lidocaine in post-cesarean section pain relief in patients performing cesarean section under general anesthesia lasting up to 24h, and both are superior to placebo in pain relief.