Objective: To study the efficacy of intravenous bolus Phenylephrine, Ephedrine and Mephentermine for maintenance of Blood Pressure during Spinal Anesthesia in patients undergoing emergency Caesarean Section.
Materials and Methods: One hundred twenty, ASA type 1 and 2 patients scheduled for emergency caesarean section under spinal anaesthesia who developed hypotension were allocated into 3 groups of 40 each. Group P received Phenylephrine 0.1mg, Group E received Ephedrine 6 mg, and Group M received Mephentermine 6 mg in 1 ml as bolus IV.
Results: The rise of diastolic blood pressure at 2, 4, and 6 minutes post study drugs were significantly less in Ephedrine and Mephentermine group as compared to the Phenylephrine group (p<0.05). Similarly elevation of systolic blood pressure in Phenylephrine group was significantly higher as compared to other two groups for first 6 minutes. Thereafter the differences narrowed off. No significant differences were observed between changes in systolic and diastolic blood pressure of Ephedrine and Mephentermine group at any point of time. In Phenylephrine group, post study drug values of heart rate decreased significantly from the values at onset of the hypotension till the end of the surgery when compared to other two groups (p<0.001). Neonatal Apgar score at 1 and 5 min were >7 in all three groups.
Conclusion: Phenylephrine group had quicker control of blood pressure compared to the other two groups. However, as the time elapsed all drugs achieved comparable control of blood pressure. Phenylephrine did show some advantage over others with regard to reduction in heart rate.