EP117 Post-caesarean analgesia: effect of intrathecal administration of magnesium sulfate

<h3>Background and Aims</h3> The addition of IT magnesium sulfate (MgSO4) has been proposed to optimize the quality of blocks during spinal anesthesia. Its anti-NMDA effect may inhibit central sensitization to pain. Few studies have evaluated its impact on post-Caesarean pain. <h3>Methods</h3> Our study was a prospective, randomized, controlled, triple-blind trial involving parturients aged between 18 and 42 years scheduled for cesarean delivery. The participants were randomized into three groups, each receiving IT administration of 11 mg hyperbaric bupivacaine, 100 µg morphine, and 2.5 µg sufentanil. The control group (C) received 0.75 cc of saline solution IT, group A received 50 mg MgSO4 plus 0.25 ml saline solution and group B received 75 mg MgSO4. <h3>Results</h3> We included 91 parturients (30 in group A and B/31 group C) with comparable demographic and clinical characteristics. Characteristics of sensory and motor block were almost the same for all parturients. The time to the first analgesic request was delayed in the magnesium groups: Groups A/B versus C: respectively 343.2 ± 34.28 min and. 291.6 ± 30.13 min versus 241.2 ± 16.17 min; p = 0.04. The time to the first ambulation was earlier in groups A and B, respectively 446.0 ± 42.2 min and 510.9 ± 45.39 min vs. 581.9 ± 54.36 min (GroupC), and shivering was significantly less intense in these groups. Pain score evolution showed patients were pain-free at rest and had mild to moderate pain with movement; with lower values for group A, explaining reduced analgesic consumption postoperatively. Pain control at one month indicated that 16 parturients still experienced mild to moderate pain with movement, most having a history of previous pain sensitization. <h3>Conclusions</h3> The addition of MgSO4 IT could improve post-Caesarean analgesia. However, a larger sample is needed to validate the results.