Ultrasound-guided transversus abdominis plane block: description of a new technique and comparison with conventional systemic analgesia during laparoscopic cholecystectomy.

Background: The transversus abdominis plane (TAP) block is usually performed by landmark-based methods. This prospective, randomized, and double-blinded study was designed to describe a method of ultrasound-guided TAP block and to evaluate the intra- and postoperative analgesic efficacy in patients undergoing laparoscopic cholecystectomy under general anaesthesia with or without TAP block.

Methods: Forty-two patients undergoing laparoscopic cholecystectomy were randomized to receive standard general anaesthetic either with (Group A, n=21) or without TAP block (Group B, n=21). Ultrasound-guided bilateral TAP block was performed with a high frequent linear ultrasound probe and an in-plane needle guidance technique with 15 ml bupivacaine 5 mg ml(-1) on each side. Intraoperative use of sufentanil and postoperative demand of morphine using a patient-controlled analgesia device were recorded.

Results: Ultrasonographic visualization of the relevant anatomy, detection of the shaft and tip of the needle, and the spread of local anaesthetic were possible in all cases where a TAP block was performed. Patients in Group A received significantly less [corrected] intraoperative sufentanil and postoperative morphine compared with those in Group B [mean (SD) 8.6 (3.5) vs 23.0 (4.8) microg, P<0.01, and 10.5 (7.7) vs 22.8 (4.3) mg, P<0.05].

Conclusions: Ultrasonographic guidance enables exact placement of the local anaesthetic for TAP blocks. In patients undergoing laparoscopic cholecystectomy under standard general anaesthetic, ultrasound-guided TAP block substantially reduced the perioperative opioid consumption.