Comparison Between 3 Different Norepinephrine Bolus Doses for Management of Postspinal Hypotension During the Caesarean Section for Patients with Preeclampsia: A Randomized Controlled Trial

Background: There is no established dose for norepinephrine (NE) in the management of postspinal hypotension. The data on its use in women with preeclampsia (PE) are limited. Objectives: This study aimed to compare the effect of using different NE bolus doses for the management of postspinal hypotension during lower segment cesarean section for patients with PE. Methods: This randomized, double-blind trial included mothers with PE scheduled for cesarean delivery who developed postspinal hypotension. Sixty participants were allocated to receive 3, 4, or 5 µg of NE bolus. The primary outcome was the neonatal bicarbonate level. The secondary outcomes were successful management of hypotension, incidence of reactive hypertension, nausea, vomiting, systolic blood pressure (SBP), and heart rate (HR) readings through the operation, umbilical blood gases, and Apgar scores. Results: The number of hypotensive episodes, bradycardia episodes, successfully treated hypotensive episodes, and total NE dose per patient were lower in the 4- and 5-µg groups compared with the 3-µg group. Systolic blood pressure was generally higher in the 4- and 5-µg groups than in the 3-µg group starting from 12 min postspinal till 28 min postspinal. The heart rate decreased compared to the baseline reading starting from 4, 6, and 2 min postspinal in the 3-, 4-, and 5-µg groups, respectively, till 28 min postspinal. Also, HR was higher in the 4- and 5-µg groups compared to the 3-µg group at 6-12 min postspinal. Following the first NE bolus, SBP remained lower than the baseline reading in the 3 groups, and HR decreased compared to the baseline reading in the 3- and 5-µg groups only. Conclusions: The 3-, 4-, and 5-µg doses had comparable efficacy in managing the first hypotensive episode and comparable neonatal outcomes. The 4- and 5-µg doses significantly decreased the total NE requirements and the number of hypotensive episodes. The incidence of maternal bradycardia was not significantly different between the groups.