The transversus abdominis plane block in conjunction with intrathecal morphine use after cesarean section in women with severe pre-eclampsia: a randomized controlled trial

BACKGROUND: The transversus abdominis plane (TAP) block in conjunction with intrathecal morphine has been demonstrated to provide more superior postcesarean analgesia to intrathecal morphine alone. However, the analgesia efficacy of their conjunction has not been demonstrated in patients with severe pre-eclampsia. The study aimed to compare the postcesarean analgesia of TAP block in conjunction with intrathecal morphine versus intrathecal morphine alone in women with severe pre-eclampsia. METHODS: Pregnant women with severe pre-eclampsia undergoing planned cesarean section were randomly allocated into 2 groups to receive TAP block with 20 ml of 0.35% Ropivacaine (TAP group) or with the same volume of 0.9% saline (Sham group) after undergoing elective cesarean section under spinal anaesthesia with 15 mg of 0.5% Ropivacaine plus 0.1 mg of morphine. The outcomes for this analysis include the visual analog scale (VAS) pain score at rest and with movement at 4,8,12,24 h after TAP block was performed, times of use of intravenous patient-controlled analgesia (PCA) within 12 h after anesthesia, the occurrence of maternal side effects, maternal satisfaction, and Apgar score at 1 and 5 min of newborns. RESULTS: 119 subjects receive TAP block with 0.35% Ropivacaine (n = 59)or 0.9% saline (n = 60). At 4,8, 12 h after TAP block, the TAP group reported lower VAS score at rest [at 4 h: 1(0,1) vs. 1(1,2), P < 0.001; at 8 h:1(1,1) vs. 1(1.5,2),P < 0.001; at 12 h:1(1,2) vs. 2(1,2),P = 0.001] and higher satisfaction [53(89.9%) vs.45(75.0%), P < 0.05]. There were no differences between groups in VAS score at 24 h at rest and at all time points above with movement, times of use of PCA within 12 h after anesthesia, maternal side-effect, and Apgar score at 1 and 5 min of newborns. CONCLUSIONS: In conclusion, The TAP block performed in conjunction with intrathecal morphine may not reduce opioid consumption, but it could reduce VAS scores at rest in the first 12 h after cesarean section in women with severe pre-eclampsia, and improve maternal satisfaction, which is worthy of clinical promotion. TRIAL REGISTRATION: Registered at Chinese Clinical Trial Registry(http://www.chictr.org.cn) on 13/12/2021: ChiCTR2100054293.