A Clinical Trial on the Effects of Different Regimens of Phenylephrine on Maternal Hemodynamic After Spinal Anesthesia for Cesarean Section

Phenylephrine is used to prevent and treat hypotension during spinal anesthesia for cesarean delivery.

The present study aims to investigate the effects of different regimens of phenylephrine on blood pressure of candidates for the cesarean section.

In this double-blind, randomized clinical trial, a total of 120 candidates of elective cesarean delivery under spinal anesthesia was randomly categorized into three groups. Groups 1, 2, and 3 received bolus and prophylactic saline (control group), prophylactic bolus phenylephrine (100 µg), and prophylactic phenylephrine infusion (50 µg/min), respectively. The incidence of hypotension, maternal hemodynamics, hypertension, rescue phenylephrine dose, nausea, and vomit were compared between the groups.

In all the three groups, the incidence of nausea and vomit, bradycardia, hypertension, and neonatal Apgar score were not statistically different (P > 0.05). However, the adjuvant phenylephrine dose requirement was remarkably different. Moreover, the mean systolic blood pressure differed significantly in the second and 7th minutes after the spinal block (P < 0.05). 35% in the first group, 15% in the second group, and 2.5% in the third group had hypotension (P = 0.001). Apart from the first measurement after spinal anesthesia, the mean heart rate showed no significant difference between the groups.

The use of prophylactic phenylephrine infusion is recommended to control the optimal blood pressure in parturients undergoing cesarean section after spinal anesthesia.