A randomized clinical trial of intrathecal magnesium sulfate versus midazolam with epidural administration of 0.75% ropivacaine for patients with preeclampsia scheduled for elective cesarean section.

Background and Aims: Magnesium sulfate and midazolam have been used as adjuvants to local anesthetics via intrathecal and epidural routes to augment the quality of block and prolong postoperative analgesia. This study compares addition of intrathecal magnesium sulfate versus intrathecal midazolam to epidurally administered isobaric ropivacaine as a part of combined spinal epidural technique in pre-eclamptic parturients undergoing elective cesarean section.

Material and Methods: After institutional ethics committee approval and written informed consent, 50 pre-eclamptic parturients were randomly allocated to one of the two groups of 25 each to either receive intrathecal magnesium sulfate (50 mg) or intrathecal midazolam (1 mg) in combination with epidural ropivacaine (0.75%; 14-16 ml). The onset and duration of sensory and motor blockade, duration of postoperative analgesia, postoperative visual analogue scores for pain, and perioperative side effects were noted. Data were analyzed statistically using Graphpad.com software.

Results: Onset times to sensory and motor blockade were faster in midazolam than in magnesium group ( P < 0.01). Duration of sensory and motor blockade, and time to first request of analgesia were significantly longer in the magnesium group compared to the midazolam group ( P < 0.01). The fetal outcomes according to APGAR scores were comparable in both the groups, the median APGAR score at 1 minute was 8 and at 5 minutes was 10 in both the groups.

Conclusion: Intrathecal magnesium with epidural ropivacaine significantly prolonged postoperative analgesia compared to intrathecal midazolam without any complications. Perioperative hemodynamics were comparable in both groups.