Maternal and Fetal Response to Pre Anesthetic ‎Magnesium Sulphate in Cesarean Section

Background: Magnesium, the fourth most common cation in the body, has an ‎antagonistic effect at the N-methyl-D-aspartate (NMDA) receptor, as ‎well as calcium-channel blocker properties. Antagonism at the ‎NMDA receptor is thought to alter the mechanism of central ‎hypersensitivity and to subsequently decrease analgesic requirements ‎including opioid consumption.‎‎ This study aimed to assess the effects of preoperative administration of intravenous magnesium sulphate on the intubation stress response as a primary outcome and uterine, fetal middle cerebral and umbilical arterial blood flow, Apgar score and postoperative analgesia as secondary outcomes in participants undergoing elective caesarian section under general anesthesia.

Methods: This prospective randomized controlled double blinded study ‎was carried out on 65 pregnant females between 21-35 years old undergoing elective caesarian section under general anesthesia. who were randomly classified randomly into two groups: Magnesium sulphate (Mg) group: received 25 mg/kg magnesium sulphate in 100 ml isotonic saline over 10 minutes before induction of anesthesia. Control group (C): received the same volume of isotonic saline over the same period.

Results: Heart rate and mean arterial blood pressure were decreased significantly at post induction to the end of surgery in mg sulphate compared to control group and was insignificantly different between the studied groups at T0 and T1. VAS was significantly lower in mg sulphate group compared to control group at 1, 2, 4, 8, 12 and 24 hours and was insignificantly different among the two groups at PACU admission and 30 min. preoperative administration of magnesium sulphate (25 mg/kg) was associated with lower postoperative pain scores, less post-operative analgesic consumption, better hemodynamic stability without significant difference in umbilical, middle cerebral and uterine arteries blood flow or Apgar score compared to control group in patients undergoing cesarean section under general anesthesia. There was no statistically significant difference in the incidence of sedation and hypotension. No cases showed respiratory depression in the two groups.

Conclusion: Preoperative administration of ‎magnesium sulphate (25mg/kg) was associated with better ‎hemodynamic stability, lower postoperative pain scores, less post-‎operative analgesic consumption without significant difference in ‎umbilical, middle cerebral and uterine arteries blood flow or Apgar ‎score with nil complications except for PONV compared to control ‎group in patients undergoing cesarean section under general ‎anesthesia.‎‎