Tracheal intubation for cesarean section is usually performed with rapid sequence induction. Under this light stage of anesthesia, marked hypertensive changes of maternal hemodynamic responses following tracheal intubation may occur, which are the common cause of maternal and neonatal complications. We have studied the maternal cardiovascular blunting effect of magnesium sulfate following tracheal intubation in cesarean section.

After obtaining the written informed consents, ninety ASA class I parturients scheduled for cesarean section were randomly allocated to one of three groups: group 1 received thiopental 4 mg/kg and succinylcholine 1.5 mg/kg, group 2 received fentanyl 1.5 microgramg/kg additionally, and group 3 received fentanyl 1.5 microgramg/kg and MgSO4 40 mg/kg additionally. Systolic, mean, diastolic blood pressure, and heart rate were measured before induction, immediately after intubation. Serum magnesium concentrations were measured before administering magnesium and near the end of surgery. Train of four ratio was monitored during whole period of anesthesia. Neonatal Apgar scores and neurologic and adaptive capacity scores (NACS) were checked.

Blood pressure changes were more stable in group 2 and group 3, especially group 3, than group 1 (p<0.05). No statistical differences were found in heart rate changes in all groups. No significant differences were noted in neuromuscular recoveries, neonatal Apgar scores and NACS.

Magnesium sulfate may be successfully used for blunting the cardiovascular response to tracheal intubation in parturients undergoing general anesthesia for cesarean section.