Norepinephrine or phenylephrine during spinal anaesthesia for Caesarean delivery: a randomised double-blind pragmatic non-inferiority study of neonatal outcome
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AbstractBackground: Norepinephrine is an effective vasopressor during spinal anaesthesia for Caesarean delivery. However, before it can be fully recommended, possible adverse effects on neonatal outcome should be excluded. We aimed to test the hypothesis that umbilical arterial cord pH is at least as good (non-inferior) when norepinephrine is used compared with phenylephrine for treatment of hypotension.
Methods: We enrolled 668 subjects having elective and non-elective Caesarean delivery under spinal or combined spinal-epidural anaesthesia in this randomised, double-blind, two-arm parallel, non-inferiority clinical trial. Arterial blood pressure was maintained using norepinephrine 6 µg/ml or phenylephrine 100µg/ml according to the practice of the anaesthetist, either prophylactically or therapeutically, as an infusion or bolus. The primary outcome was umbilical arterial pH with a chosen non-inferiority margin of 0.01 units.
Results: Of 664 subjects (531 elective and 133 non-elective) who completed the study, umbilical arterial cord blood was analysed for 351 samples from 332 subjects in the norepinephrine group and 343 samples from 332 subjects in the phenylephrine group. Umbilical arterial pH was non-inferior in the norepinephrine group (mean, 7.289; 95% confidence interval [CI], 7.284-7.294) compared with the phenylephrine group (mean, 7.287; 95% CI, 7.281-7.292) (mean difference between groups, 0.002; 95% CI, -0.005 to 0.009; P=0.017). Subgroup analysis confirmed the non-inferiority of norepinephrine for elective cases but was inconclusive for non-elective cases.
Conclusions: Norepinephrine was non-inferior to phenylephrine for neonatal outcome assessed by umbilical arterial pH. These results provide high-quality evidence supporting the fetal safety of norepinephrine in obstetric anaesthesia.
Acceptance Date20/05/2020
All Author(s) ListWarwick D. Ngan Kee, Shara WY Lee, Floria F Ng, Anna Lee
Journal nameBritish Journal of Anaesthesia
Year2020
Month10
Volume Number125
Issue Number4
PublisherElsevier
Pages588 - 595
ISSN0007-0912
eISSN1471-6771
LanguagesEnglish-United Kingdom
KeywordsCaesarean delivery, hypotension, norepinephrine, obstetric anaesthesia, phenylephrine, spinal anaesthesia

Last updated on 2021-17-09 at 00:26