Comparative Analysis Of Phenylephrine Infusion Vs Bolus Dose To Prevent Maternal Hypotension During Elective Cesarean Section At Women And Children Hospital, Charsadda

Abstract

Background: Maternal hypotension is a common complication of spinal anesthesia during elective cesarean section, potentially affecting both maternal and neonatal outcomes. Phenylephrine, a selective α1-adrenergic agonist, is widely used to prevent hypotension, administered either as intermittent bolus or continuous infusion. This study aimed to compare the effectiveness of phenylephrine infusion versus bolus dosing in maintaining maternal hemodynamic stability during elective cesarean section.

Methods: A comparative cross-sectional study was conducted at the Gynecology Department, Women and Children Hospital Rajjar, Charsadda, from May 16 to July 16, 2025. A total of 120 parturients meeting inclusion criteria were enrolled and divided into two groups: 60 received phenylephrine infusion, and 60 received phenylephrine bolus. Baseline vitals were recorded, and spinal anesthesia was performed using 0.75% bupivacaine. Systolic and diastolic blood pressures were monitored at 3-minute intervals until delivery. Maternal hypotension was defined as a ≥20% reduction in baseline systolic blood pressure. Primary outcome was incidence of hypotension; secondary outcomes included total phenylephrine dose, incidence of bradycardia, maternal nausea and vomiting, and neonatal APGAR scores. Data were analyzed using SPSS 27.0, with Chi-square tests for group comparisons.

Results: Effectiveness in maintaining SBP within 20% of baseline was higher in the infusion group (90%) compared to the bolus group (80%) (χ² = 3.84, p = 0.05). SBP decreased in both groups after spinal anesthesia, with the bolus group showing significantly higher SBP at 3 and 9 minutes (p < 0.001 and p = 0.034, respectively). The infusion group maintained significantly higher diastolic blood pressure at multiple time points (p < 0.05). Neonatal APGAR scores were normal in all cases, with no significant adverse events observed.

Conclusion: Both phenylephrine infusion and bolus dosing effectively prevent maternal hypotension during cesarean section under spinal anesthesia. Bolus dosing rapidly corrects low blood pressure at critical time points, while infusion provides smoother and more stable control of diastolic pressure. Both methods are safe for neonates, and the choice between infusion and bolus should be tailored to maternal needs and intraoperative monitoring.