A randomized-controlled trial comparing liposomal bupivacaine, plain bupivacaine, and the mixture of liposomal bupivacaine and plain bupivacaine in transversus abdominus plane block for postoperative analgesia for open abdominal hysterectomies; [Une étude randomisée contrôlée comparant la bupivacaïne liposomale, la bupivacaïne simple, et le mélange de bupivacaïne liposomale et de bupivacaïne simple pour un bloc du plan transverse de l’abdomen pour l’analgésie postopératoire après une hystérectomie abdominale par laparotomie]

Purpose: Transversus abdominus plane (TAP) blocks are widely used for postoperative analgesia for abdominal surgical procedures. The purpose of this study was to compare the analgesic efficacy of plain bupivacaine, liposomal bupivacaine, and the mixture of plain bupivacaine with liposomal bupivacaine when used in a TAP block. Methods: This study was a single centre, prospective, patient-, observer-, and surgeon-blinded, randomized-controlled trial in which 90 patients undergoing an open abdominal hysterectomy with a midline incision were randomized to receive a TAP block with plain bupivacaine (group bupivacaine), liposomal bupivacaine (group liposomal), or a mixture of liposomal bupivacaine and plain bupivacaine (group mixture). Primary outcomes included time to the first rescue opioid analgesic and total opioid consumption during the first 72 postoperative hours. Secondary outcomes included pain scores, patient satisfaction, incidence of hemodynamic instability, presence of local anesthetic systemic toxicity, and length of hospital stay. Results: The median [interquartile range] time to first opioid was 51 [28–66] min in group bupivacaine, 63 [44–102] min in group liposomal, and 51 [24–84] min in group mixture (P = 0.20). The median [interquartile range] total opioid consumption in the first 72 postoperative hours was 208 [155–270] mg in group bupivacaine, 203 [153–283] mg in group liposomal, and 202 [116–325] mg in group mixture (P = 0.92). There were no significant differences in secondary outcomes between groups. Conclusions: In this small study at risk of being under-powered, the mixture of liposomal bupivacaine with plain bupivacaine for TAP block did not improve analgesia compared with either liposomal bupivacaine or plain bupivacaine on their own. Trial registration: www.clinicaltrials.gov (NCT03250507); registered 5 April 2017. © 2021, Canadian Anesthesiologists' Society.