Randomized trial of transversus abdominis plane block with liposomal bupivacaine after cesarean delivery with or without intrathecal morphine

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Study objectiveTo investigate efficacy and safety of liposomal bupivacaine (LB) transversus abdominis plane (TAP) block with or without intrathecal morphine (ITM) compared with ITM alone for postsurgical analgesia after cesarean delivery (CD). DesignMulticenter, open-label, randomized trial (NCT03853694). SettingOperating room. PatientsWomen with term pregnancy of 37 to 42 weeks scheduled for elective CD under spinal anesthesia. InterventionPatients were randomized 1:1:1 to LB 266 mg TAP block alone (LB group), ITM 50 μg followed by LB 266 mg TAP block (LB + ITM group), or ITM 150 μg alone (ITM group). All groups received the same postsurgical multimodal analgesic regimen. MeasurementsThe LB and LB + ITM groups were compared with the ITM group for all efficacy outcomes. Postsurgical opioid consumption in morphine milligram equivalents (MMEs) through 72 h was compared by assessing noninferiority before testing superiority. Postsurgical pruritus severity was assessed on an 11-point numerical rating scale. Main resultsBetween March 4, 2019, and January 10, 2020, 153 patients (LB, n = 52; LB + ITM, n = 48; ITM, n = 53) were enrolled. Baseline characteristics were comparable across groups. The LB group had statistically noninferior postsurgical opioid consumption through 72 h compared with the ITM group (least squares mean [LSM], 19.2 vs 16.4 MMEs; LSM treatment ratio, 1.17 [95% confidence interval (CI), 0.74–1.86]; noninferiority P < 0.0034) as did the LB + ITM group (LSM, 14.6 vs 16.4 MMEs; LSM treatment ratio, 0.89 [95% CI, 0.55–1.44]; noninferiority P < 0.0001). The LB and LB + ITM groups had significantly reduced pruritus severity scores through 12, 24, 48, and 72 h compared with the ITM group (P ≤ 0.0121). Adverse events occurred in 58%, 85%, and 81% of the LB, LB + ITM, and ITM groups, respectively. ConclusionsLB TAP block with or without ITM resulted in statistically noninferior postsurgical opioid consumption through 72 h, reduced pruritus, and favorable safety compared with ITM in women undergoing CD.