Effects of continuous infusion of phenylephrine vs. norepinephrine on parturients and fetuses under LiDCOrapid monitoring: A randomized, double-blind, placebo-controlled study

Abstract

Background: Hypotension following spinal anesthesia (SA) during cesarean delivery (CD) occurs commonly and is related with maternal and fetal complications. Norepinephrine infusion is increasingly used for prevention of post-SA hypotension; however, its effects as compared to the traditional phenylephrine infusion remain unclear. This study aimed to compare the effects of phenylephrine and norepinephrine administered as continuous infusion during elective CD on maternal hemodynamic parameters and maternal and fetal outcomes.Methods: This prospective, single-center, randomized, controlled study included 238 consecutive term parturients who underwent CD from February 2019 to October 2019. They were randomized to receive continuous infusion of 0.25 μg/kg/min phenylephrine, 0.05 μg/kg/min norepinephrine, or placebo. Hemodynamic monitoring was performed at 10 time points using LiDCOrapid. We analyzed umbilical vein (UV), umbilical artery (UA), and peripheral vein (PV) blood gas indexes and recorded intraoperative complications.Results: In phenylephrine group, the systolic blood pressure (SBP) remain during the whole operation. Compared to the control group, phenylephrine, but not norepinephrine, significantly increased the systemic vascular resistance (SVR) to counteract the SA-induced vasodilatation, 3 min following norepinephrine/phenylephrine/LR administration (T4): 957.4±590.3 vs 590.1±273.7 (P<0.000001); 5 min following norepinephrine/phenylephrine/LR administration (T5): 1104±468.0 vs 789.4±376.2 (P=0.000002). at the time of incision (T6): 1084±524.8 vs 825.2± 428.6 (P=0.000188). Parturients in the phenylephrine group had significantly lower UV (1.91±0.43) (P=0.0003) and UA (2.05±0.61) (P=0.0038) lactate level compared to controls. Moreover, the UV pH value was higher in the phenylephrine than in the control group7.37±0.03(P=0.0013). Parturients had lower incidence of nausea, tachycardia, hypotension in phenylephrine group.Conclusions: In this dataset, continuous phenylephrine infusion reduced the incidence of SA-induced hypotension, ameliorated SVR, while decreasing overall maternal complications. Phenylephrine infusions are considered the better choice during CD because of the significant benefit to the fetus.Trial registration: Clinicaltrial.gov Registry, NCT03833895, Registered on 1 February 2019.

Norepinephrine Versus Phenylephrine Infusion for Preventing Postspinal Hypotension During Cesarean Section for Twin Pregnancy: A Double-Blinded Randomized Controlled Clinical Trial

“…Similar to the results from previous study with singleton pregnancy, infusion of norepinephrine was not associated with greater heart rate [10] or greater CO [15], in patients twin pregnancy receiving spinal anesthesia for cesarean delivery. Although the incidence of bradycardia was higher in patients receiving phenylephrine, the requirements of atropine were not different between the two vasopressors.…”

Manually Controlled, Continuous Infusion of Phenylephrine or Norepinephrine for Maintenance of Blood Pressure and Cardiac Output During Spinal Anesthesia for Cesarean Delivery: A Double-Blinded Randomized Study

“…In 2 other randomized trials comparing fixed-rate infusion of norepinephrine or phenylephrine with rescue vasopressor boluses, 7,21 no difference in CO between groups was observed. Of note, in these latter 2 studies, 7,21 CO was measured by pulse contour analysis of the arterial pressure curve, a method whose reliability is markedly altered by changes in arterial tone such as those obtained with vasopressor boluses. 24,25 In the former trial, 6 like in other studies, 4,26 SV was measured by suprasternal Doppler and showed a consistent stability between SA and delivery in patients treated by phenylephrine.…”

“…To our knowledge, only 4 other studies 6,7,21,22 have compared the time course of CO between parturients treated by norepinephrine or phenylephrine during elective cesarean delivery. In a double-blinded randomized trial comparing computer-controlled infusion of norepinephrine or phenylephrine in 104 parturients, 6 CO (measured by the suprasternal Doppler method) and HR were higher in the norepinephrine group.…”

“…Notably, we observed a percentage of nausea/vomiting in both groups of 30% to 40%, which is much higher than previously reported. 6,21 This may be ascribed to the use of sufentanyl and morphine 30,31 for SA without antiemetic prophylaxis and the long observation period during which this side effect occurrence was collected (70 minutes on average until the weaning of the vasopressor).…”

“…In fact, only mild differences in CO or HR were observed at any time point between SA and umbilical cord clamping. In 2 other randomized trials comparing fixedrate infusion of norepinephrine or phenylephrine with rescue vasopressor boluses, 7,21 no difference in CO between groups was observed. Of note, in these latter 2 studies, 7,21 CO was measured by pulse contour analysis of the arterial pressure curve, a method whose reliability is markedly altered by changes in arterial tone such as those obtained with vasopressor boluses.…”