Comparative study of norepinephrine and phenylephrine infusion for prophylaxis against post-spinal hypotension in patients undergoing elective cesarean section

Abstract

Background: Maternal hypotension is a physiological response during cesarean section (CS) with spinal anesthesia (SA) and can cause adverse maternal and fetal outcomes. Aim: The present study aimed at comparing the efficacy and safety of norepinephrine and phenylephrine infusion in a CS under SA. Methods: In a randomized clinical trial, 164 ASA I and II parturients undergoing CS under SA were randomized to have a prophylactic infusion of norepinephrine 0.05 µg/kg/min (group N) or phenylephrine 0.75µg/kg/min (group P). The primary outcome was the incidence of post-spinal hypotension. Incidence of severe post-spinal hypotension, reactive hypertension, and bradycardia, total vasopressor rescue bolus doses required, number of physician interventions, nausea and vomiting, and Apgar score at 1 and 5 mins were secondary outcomes. Results: The incidence of post-spinal hypotension in group P (24 %) and group N (29.26 %); severe post-spinal hypotension in group P (3.6 %) and group N (2.4%) respectively and were comparable (p-value >0.05). No of bolus dose of vasopressor required between the two groups, and the incidence of bradycardia and reactive hypertension were comparable. Nausea and vomiting were very low in both groups and comparable. The number of physician interventions needed was significantly higher in group P (39.02%) compared to group N (28.04%) (p-value < 0.05). Conclusion: Norepinephrine is associated with a lower number of physician interventions as compared to phenylephrine; otherwise, hemodynamics is comparable when used to prevent hypotension.

Keywords

• norepenephrine
• phenylephrine
• caesarean section
• spinal anaesthesia