Postoperative analgesic effects of ultrasound-guided transversus abdominis plane block for open appendectomy

Purpose: Transversus abdominis plane (TAP) block is a newly developed and effective peripheral block involving the nerves of the anterior abdominal wall for lower abdominal surgery. We evaluated the postoperative analgesic efficacy of ultrasound-guided TAP block using 20 mL of 0.5% levobupivacaine in patients undergoing open appendectomy. Methods: Forty-four patients undergoing appendectomy were assigned either to undergo a right sided-TAP block (group I, n = 22), or to receive standard care (group II, n = 22). All patients received standard anesthetics, and the TAP block group received ultrasound-guided right side TAP block using 20 mL of 0.5% levobupivacaine after induction of anesthesia. All patients received acetaminophen, and nonsteroidal anti-inflammatory drug as required during the 48 postoperative hours. Each patients was assessed for time to first rescue analgesia, verbal numerical rating pain scores (VNRS), number of rescue analgesic demands, nausea, vomiting, pruritus, and drowsiness by a blinded investigator at 0, 1, 3, 6, 12, 24 and 48 hours postoperatively. Results: The TAP block group with levobupivacaine compared to the control group reduced VNRS significantly up to 12 hours postoperatively. There were no significant differences in time to first analgesia, number of rescue analgesics demands, nausea, vomiting, pruritus and drowsiness between the groups. There were no complications attributable to the TAP block. Conclusion: Ultrasound-guided TAP block using 20 mL of 0.5% levobupivacaine provided effective postoperative analgesia during the 12 postoperative hours after an open appendectomy.