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. 2014 Mar 3:5:81.
doi: 10.3389/fphys.2014.00081. eCollection 2014.

Effect of phenylephrine vs. ephedrine on frontal lobe oxygenation during caesarean section with spinal anesthesia: an open label randomized controlled trial

Visti T Foss  1 , Robin Christensen  2 , Kim Z Rokamp  1 , Peter Nissen  3 , Niels H Secher  3 , Henning B Nielsen  3
Affiliations

Effect of phenylephrine vs. ephedrine on frontal lobe oxygenation during caesarean section with spinal anesthesia: an open label randomized controlled trial

Visti T Foss et al. Front Physiol. .

Abstract

Background: During caesarean section spinal anesthesia 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 anesthesia is not known.

Objectives: To evaluate the impact of phenylephrine vs. ephedrine on ScO2during caesarean section with spinal anesthesia in a single center, 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 hemodynamics and fetal 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 ScO2between 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 fetal 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 anesthesia, ephedrine maintains frontal lobe oxygenation and maternal heart rate with a similar increase in fetal heart rate as elicited by phenylephrine.

Trial registration: Clinical trials NCT 01509521 and EudraCT 2001 006103 35.

Trial registration: ClinicalTrials.gov NCT01509521.

Keywords: cerebral autoregulation; drug effect; fetal; heart rate; near infrared spectroscopy; vasoconstrictor agents.

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Figures

Figure 1
Figure 1
Trial profile.
Figure 2
Figure 2
Change in ScO2 from baseline. Changes in frontal lobe oxygenation (ScO2; % from baseline) during caesarean section with spinal anesthesia. Patients received either phenylephrine (n = 12; open circles) or ephedrine (n = 12; black circles).
Figure 3
Figure 3
Change in mean arterial pressure from baseline. Changes in mean arterial blood pressure (MAP) from baseline (mmHg) during caesarean section with spinal anesthesia. Patients received either phenylephrine (n = 12; open circles) or ephedrine (n = 12; black circles).
Figure 4
Figure 4
Foetal heart rate. Change in fetal heart rate (bpm) after induction (2.5–5 min), before surgery (7.5–17.5 min), after delivery (12.5–27.5 min) in two groups of 12 patients undergoing spinal anesthesia for caesarean section and receiving either phenylephrine (open circles) or ephedrine (black circles).
See this image and copyright information in PMC

References

    1. Berlac P. A., Rasmussen Y. H. (2005). Per-operative cerebral near-infrared spectroscopy (NIRS) predicts maternal hypotension during elective caesarean delivery in spinal anaesthesia. Int. J. Obstet. Anesth. 14, 26–31 10.1016/j.ijoa.2004.06.003 - DOI - PubMed
    1. Bogert L. W., van Lieshout J. J. (2005). Non-invasive pulsatile arterial pressure and stroke volume changes from the human finger. Exp. Physiol. 90, 437–446 10.1113/expphysiol.2005.030262 - DOI - PubMed
    1. Cannesson M., Zhongping J., Chen G., Vu T. Q., Hatib F. (2012). Effects of phenylephrine on cardiac output and venous return depend on the position of the heart on the Frank-Starling relationship. J. Appl. Physiol. 113, 281–289 10.1152/japplphysiol.00126.2012 - DOI - PubMed
    1. Choi J., Wolf M., Toronov V., Wolf U., Polzonetti C., Hueber D., et al. (2004). Noninvasive determination of the optical properties of adult brain: near-infrared spectroscopy approach. J. Biomed. Opt. 9, 221–229 10.1117/1.1628242 - DOI - PubMed
    1. Cyna A. M., Andrew M., Emmett R. S., Middleton P., Simmons S. W. (2006). Techniques for preventing hypotension during spinal anaesthesia for caesarean section. Cochrane Database Syst. Rev. 4:CD002251 10.1002/14651858.CD002251.pub2 - DOI - PubMed

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