///2019 Abstract Details
2019 Abstract Details2019-07-13T07:45:15-05:00

A randomized double-blind study comparing prophylactic norepinephrine and ephedrine infusion for maternal spinal hypotension during cesarean section

Abstract Number: T2B-216
Abstract Type: Original Research

Mao Mao Master1 ; Xian Wang Doctor2; XiaoFeng Shen Master3; ShiQin Xu Master4

Background: Many studies have shown the efficacy of norepinephrine for treatment of spinal hypotension during cesarean section via comparing to phenylephrine. However, there has been little research into the comparison between norepinephrine and ephedrine, another commonly used vasopressor, when used for management of maternal hemodynamics.

Methods: Ninety-seven parturients scheduled for elective cesarean section were randomly assigned to receive prophylactic infusion of norepinephrine 4 μg/min (group N; n=48) or ephedrine 4 mg/min (group E; n = 49) immediately post spinal anesthesia with systolic blood pressure (SBP) targeted at 80-120% of baseline. Rescue bolus norepinephrine 8 μg was given whenever SBP reached the predefined lower limit. Our primary outcomes were maternal SBP and heart rate (HR). Secondary outcomes included incidence of tachycardia (HR >100bpm), bradycardia (HR < 60 bpm), hypertension (SBP > 120% baseline), hypotension (HR < 80% of baseline), as well as hypotensive episodes, number of rescue top-ups, and hemodynamic control precision including median performance error (MDPE) and median absolute performance error (MDAPE). Maternal side effects including headache, nausea, vomiting, dizziness, chest pain, short of breath, shivering, as well as neonatal Apgar scores, umbilical arterial (UA) blood gas and pH were collected as well.

Results: SBP and HR throughout the observational time points was comparable between groups. However, standardized SBP and HR over time was lower in group N compared to group E (87.2 ± 9.6 vs. 91.4 ± 9.5, P = 0.04, difference: 4.1 ± 1.9 [95% confidence interval {CI}: 0.27 to 8.0], and 70.3 ± 11 vs. 75 ± 11, P = 0.04, difference: 4.7 ± 2.2 [95% CI: 0.24 to 9.1], respectively). Further, women in group N experienced fewer cases of tachycardia (4.2% vs. 30.6%, P = 0.002, odds ratio: 0.11 [95% CI: 0.02 to 0.47]) and a lower MDPE for HR (1.3 ± 9.6 vs. 8.4 ± 13.5 bpm, P = 0.003, difference: 3.1 ± 1.8 [95% CI: -0.6 to 6.7]). Furthermore, UA blood gas showed a higher base excess (BE) and a lower lactate in group N compared to group E (both P < 0.001). Other hemodynamics variables, as well as maternal side effects and neonatal outcomes were similar between groups.

Conclusion: Our data report norepinephrine infusion at 4 μg/min was slightly inferior to equipotent ephedrine infusion at 4 mg/min for SBP maintenance; however, it presents fewer cases of tachycardia, a less fluctuation of HR, and a less stressed fetal status compared to ephedrine.

SOAP 2019