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Abstract

Background: Hypotension is a common complication during caesarean sections performed under subarachnoid block, posing risks to both mother and fetus. Vasopressors like phenylephrine and mephentermine are commonly used to manage this condition. This study compares the efficacy and side-effect profiles of intravenous bolus doses of phenylephrine and mephentermine in treating intraoperative hypotension.
Methods: This randomized, parallel-group clinical trial included 80 parturients undergoing caesarean section under spinal anaesthesia. Participants were allocated into two groups: Group M received 6 mg mephentermine IV bolus; Group P received 100 µg phenylephrine IV bolus. Hemodynamic parameters, need for rescue vasopressor doses, and adverse effects were recorded and statistically analyzed.
Results: Both vasopressors effectively maintained systolic and diastolic blood pressure, mean arterial pressure, and heart rate with no statistically significant differences in most parameters. However, Group P required significantly fewer rescue doses (25% vs. 62.5%; p < 0.001). Tachycardia was significantly more common in Group M (25% vs. 0%; p = 0.001), while bradycardia and nausea/vomiting occurred at similar rates in both groups.
Conclusion: Both phenylephrine and mephentermine are effective in managing spinal-induced hypotension during caesarean sections. Phenylephrine showed a better hemodynamic stability profile with fewer rescue doses and lower incidence of tachycardia, making it a potentially preferable choice in clinical practice.