Liposomal Bupivacaine, Plain Bupivacaine, and Saline for Transversus Abdominis Plane Blocks: The CLEVELAND Randomized Trial.

Abstract

Enhanced Recovery After Surgery pathways recommend transversus abdominis plane (TAP) blocks, but their efficacy is controversial and limited by the duration of local anesthetics. Liposomal bupivacaine is commonly used in single-injection TAP blocks to extend analgesia, although its effectiveness remains unclear. Therefore, two coprimary hypotheses were tested: first, that opioid consumption during the initial 24 postoperative hours is higher with saline than plain bupivacaine or liposomal bupivacaine; and second, that opioid consumption between 24 to 48 h after surgery is comparable or greater with saline or plain bupivacaine than with liposomal bupivacaine. Patients having major abdominal surgery ( e.g. , colorectal, gynecological, hernia repairs) were enrolled and randomly assigned 1:1:1 to bilateral four-quadrant TAP blocks with liposomal bupivacaine (40 ml plain bupivacaine 0.25% with 20 ml liposomal bupivacaine and 20 ml saline), plain bupivacaine (50 ml plain bupivacaine 0.5% with 30 ml normal saline), and placebo (80 ml normal saline). Patient-controlled intravenous opioids were used as needed. Patients, clinicians who adjusted opioid analgesia, ward nurses who evaluated pain scores, and study investigators who evaluated local anesthetic effects were blinded to treatment groups. In the modified intention-to-treat cohort of 261 patients, opioid requirements during the first 24 h were median [interquartile range] 26 [18, 48] milligram morphine equivalents (MME) for liposomal bupivacaine (n = 89), 33 [13, 75] MME for plain bupivacaine (n = 84), and 31 [17, 53] MME for placebo (n = 88). The estimated ratio of geometric means was 0.86 (97.7% CI, 0.60 to 1.24; P = 0.355) between liposomal bupivacaine and placebo groups, and 0.91 (97.7% CI, 0.63 to 1.32; P = 0.578) between plain bupivacaine and placebo groups. Opioid requirements between 24 and 48 h were also comparable across groups. Secondary outcomes, including time to sensation return, pain scores, and opioid requirements from 48 to 72 h, were similar across all groups, with no significant differences observed. Single-shot, four-quadrant TAP blocks performed with liposomal bupivacaine, plain bupivacaine, or normal saline before incision for various open and laparoscopic abdominal procedures resulted in similar postoperative opioid consumption and pain scores at 24, 48, and 72 h. Absence of early benefit suggests that routine preincision, single-shot TAP blocks in this mixed surgical population provide little analgesia.