A randomized double-blind study comparing prophylactic norepinephrine and ephedrine infusion for preventing maternal spinal hypotension during elective cesarean section under spinal anesthesia: A CONSORT-compliant article

Abstract

Background:Studies have shown the efficacy of norepinephrine in the treatment of maternal hypotension during cesarean section by comparing it to treatment with phenylephrine. However, few studies have compared the efficacy of norepinephrine to ephedrine.Methods:Ninety-seven women undergoing elective cesarean section were administered norepinephrine at 4μg/minute (group N; n=48) or ephedrine at 4mg/minute (group E; n=49) immediately postspinal anesthesia, with an on-off titration to maintain systolic blood pressure (SBP) at 80% to 120% of baseline. A rescue bolus of 8μg norepinephrine was given whenever SBP reached the predefined lower limit. Our primary outcome was the incidence of tachycardia. Secondary outcomes included the incidence of bradycardia, hypertension, hypotension, severe hypotension, hypotensive episodes, number of rescue top-ups, hemodynamic performance error including median performance error (MDPE), and median absolute performance error (MDAPE). Neonatal Apgar scores and umbilical arterial (UA) blood gas data were also collected.Results:Women in group N experienced fewer cases of tachycardia (4.2% vs 30.6%, P=.002, odds ratio: 0.11 [95% confidence interval, CI: 0.02-0.47]), a lower standardized heart rate (HR) (70.3±11 vs 75±11, P=.04, difference: 4.7±2.2 [95% CI: 0.24-9.1]), and a lower MDPE for HR (1.3±9.6 vs 8.4±13.5bpm, P=.003, difference: 3.1±1.8 [95% CI: -0.6-6.7]). In addition, the lowest or the highest HR was lower in group N compared to group E (both P