Comparative Evaluation of Bolus Phenylephrine, Ephedrine, and Mephentermine for Arterial Pressure Maintenance during Spinal Anesthesia in Cesarean Section Procedures

Abstract

Background: One of the challenges frequently faced by an anaesthesiologist during a Caesarean section is the occurrence of low blood pressure following spinal anesthesia. This research aimed to compare the effectiveness of intravenous boluses of Phenylephrine, Ephedrine, and Mephentermine in maintaining arterial blood pressure during spinal anesthesia for Caesarean sections. Materials and methods: Sixty patients categorized as American Society of Anesthesiologists (ASA) types 1 and 2, scheduled for both elective and emergency Caesarean sections under spinal anesthesia, experienced episodes of hypotension. These patients were divided into three groups of 20 each. Group P received Phenylephrine at a dose of 100 micrograms, Group E received Ephedrine at 6 mg, and Group M received Mephentermine at 6 mg, all administered as a bolus intravenous injection in a 1 ml volume. Results: When comparing the three groups, it was found that the rise in diastolic blood pressure at 2, 4, and 6 minutes after administering the study drugs was notably lower in the Ephedrine and Mephentermine groups compared to the Phenylephrine group (p < 0.05). Likewise, the increase in systolic arterial pressure in the Phenylephrine group was significantly higher during the first 6 minutes, after which the differences diminished. There were no significant variations observed in the changes of systolic and diastolic blood pressure between the Ephedrine and Mephentermine groups at any given time. Additionally, in the Phenylephrine group, the post-study drug values of heart rate significantly decreased from the values at the onset of hypotension until the end of the surgery when compared to the other two groups (p < 0.001). Conclusion: The Phenylephrine group demonstrated faster control of blood pressure compared to the other two groups initially. However, over time, all three drugs achieved similar levels of blood pressure control. Notably, Phenylephrine showed an advantage over the other medications in terms of reducing heart rate.