The Analgesic Efficacy of Transversus Abdominis Plane Block After Cesarean Delivery: A Randomized Controlled Trial

Abstract

Much of the pain experienced by patients having abdominal surgery such as cesarean section comes from the abdominal wall incision. Introducing local anesthetic into the transversus abdominis plane (TAP) by way of the triangle of Petit makes it possible to block the sensory nerves of the anterior abdominal wall before they leave this plane to pierce the musculature. The TAP block has proved effective in providing analgesia in patients requiring a midline abdominal wall incision. In this randomized controlled, double-blind trial, 25 women having elective cesarean delivery were assigned to receive a bilateral TAP block at the end of surgery, using 1.5 mg/kg of 0.75% ropivacaine up to a maximum of 150 mg, while 25 others received a saline placebo. A Pfannensteil incision was made under spinal anesthesia in all cases, and all women received patient-controlled intravenous morphine postoperatively as well as diclofenac and acetaminophen. A blinded investigator evaluated patients at frequent intervals up to 48 hours postoperatively. The 2 groups were similar in age, body size, and previous abdominal surgery. Visual analog scale pain scores, recorded postoperatively, were lower in patients having a TAP block. Total morphine requirements in the first 48 postoperative hours were lower in the TAP block group, and the time to the first request for morphine was longer than in control women. Interval morphine use was significantly lower at 12, 24, and 36 hours following TAP blockade. The incidence of sedation was reduced in the actively treated group, and no complications were ascribed to the TAP block. These findings suggest that the TAP block, which is easily performed, provides reliable and effective analgesia, and is safe, should be considered as part of a multimodal analgesic regimen following cesarean delivery.