AUTHOR=Foss Visti T., Rokamp Kim Z., Christensen Robin D., Nissen Peter , Secher Niels H., Nielsen Henning B.
TITLE=Effect of phenylephrine vs. ephedrine on frontal lobe oxygenation during caesarean section with spinal anesthesia: an open label randomized controlled trial
JOURNAL=Frontiers in Physiology
VOLUME=Volume 5 - 2014
YEAR=2014
URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2014.00081
DOI=10.3389/fphys.2014.00081
ISSN=1664-042X
ABSTRACT=Background: During caesarean section spinal anaesthesia may provoke maternal hypotension that we prevent by administration of phenylephrine and/or ephedrine. Phenylephrine is however reported to reduce the near infrared spectroscopy-determined frontal lobe oxygenation (ScO2) but whether that is the case for patients exposed to spinal anaesthesia is not known.
Objectives: To evaluate the impact of phenylephrine vs. ephedrine on ScO2 during caesarean section with spinal anaesthesia in a single centre, open-label parallel-group study with balanced randomization of 24 women (1:1). Secondary aims were to compare the effect of the two drugs on maternal haemodynamics and foetal heart rate.
Intervention: Ephedrine (0.8-3.3 mg/min) vs. phenylephrine infusion (0.02-0.07 mg/min).
Results: For the duration of surgery, administration of ephedrine maintained ScO2 (compared to baseline +2.1± 2.8%;mean ± SE, while phenylephrine reduced ScO2 (-8.6 ± 2.8%; p = 0.005) with a 10.7% difference in ScO2 between groups (p=0.0106). Also maternal heart rate was maintained with ephedrine (+3 ± 3 bpm) but decreased with phenylephrine (-11 ± 3 bpm);difference 14 bpm (p=0.0053), but no significant difference in mean arterial pressure (p = 0.1904) or CO (p=0.0683) was observed between groups. The two drugs also elicited an equal increase in foetal heart rate (by 19 ± 3 vs. 18 ± 3 bpm; p=0.744).
Conclusion: In the choice between phenylephrine and ephedrine for maintenance of blood pressure during caesarean section with spinal anaesthesia, ephedrine maintains frontal lobe oxygenation and maternal heart rate with a similar increase in foetal heart rate as elicited by phenylephrine.
Trial registration: Clinical trials NCT 01509521 and EudraCT 2001 006103 35