Comparison of the Effects of Norepinephrine and Phenylephrine Infusion in Preventing Hypotension during Spinal Anesthesia for Cesarean Delivery: A Randomized, Double-Blind Clinical Trial.

Abstract

Background: Hypotension following spinal anesthesia is one of the most common complications of cesarean delivery, posing significant risks to both maternal and fetal health. The use of vasopressors is a primary method for the prevention and management of hypotension. Objective: This study aimed to compare the efficacy of norepinephrine and phenylephrine infusion in preventing hypotension in patients undergoing cesarean section under spinal anesthesia.

Methods: In this randomized, double-blind clinical trial, 90 pregnant women at 37 weeks of gestation scheduled for elective cesarean delivery were randomly assigned to receive either norepinephrine (n=47) or phenylephrine (n=43). The initial infusion rate was set at 5 µg/min for norepinephrine (up to a maximum of 60 mL/min) and 0.5 mg/min for phenylephrine (up to a maximum of 60 mL/min). Hemodynamic parameters, including systolic blood pressure (SBP) and diastolic blood pressure (DBP), mean arterial pressure (MAP), and heart rate, were assessed. Additionally, umbilical cord blood gas values (PACO₂ and pH) at the time of birth were measured. Statistical analysis was performed using SPSS version 18 with descriptive statistics and independent t-tests or Mann-Whitney U tests (P≤0.05).

Results: The findings revealed no statistically significant differences between the norepinephrine and phenylephrine groups regarding SBP and DBP, MAP, heart rate, and umbilical cord blood gas values (PACO₂ and pH) at delivery (P≥0.05).

Conclusion: Norepinephrine and phenylephrine appear to have similar efficacy in preventing hypotension during cesarean delivery. Clinicians may select either drug based on the patient's clinical conditions and preferences.