Anesthetic Conversion of Preexisting Labor Epidural Analgesia for Emergency Cesarean Section and Efficacy of Levobupivacaine with or Without Magnesium Sulphate: A Prospective Randomized Study

BACKGROUND: For pregnant women who require an emergency cesarean section (CS), extending labor epidural analgesia as quickly as feasible to good quality anesthesia is a critical issue. This indicates the presence of functional labor epidural analgesia and reduces the need for general anesthesia. Addition of magnesium increases anesthetic and analgesic qualities of epidural anesthesia. OBJECTIVES: The purpose of this trial was to assess the role of adding magnesium sulfate (MgSO(4)) with levobupivacaine to speed up the conversion of labor epidural analgesia into enough anesthesia for emergency CS. METHODS: Fifty parturients were randomly assigned to receive 19.5 mL of levobupivacaine 0.5% with either 0.5 mL of normal saline 0.9% (Group I) or 0.5 mL of MgSO(4) 10% (Group II) after receiving labor epidural analgesia. We documented the onset of block (loss of pinprick to T6), number of patients needing additional analgesia, the time needed for sensory and motor blockade to recover, and the adverse effects. RESULTS: The frequency of patients receiving intraoperative supplements was comparable in the study groups (P = 0.491), although the onset of the block was faster in Group II than in Group I (P = 0.000*). Group II took substantially longer to recover from sensory and motor blockade than Group I (P = 0.001* and P = 0.001*, respectively). In both groups, the occurrence of adverse events was similar. CONCLUSIONS: Adding 50 mg of MgSO(4) to levobupivacaine 0.5% accelerated the epidural top, and both sensory onset and motor blocks period were prolonged as compared to levobupivacaine alone when extending epidural analgesia for emergency CS.