Document Detail


Placental transfer and fetal metabolic effects of phenylephrine and ephedrine during spinal anesthesia for cesarean delivery.
MedLine Citation:
PMID:  19672175     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Use of ephedrine in obstetric patients is associated with depression of fetal acid-base status. The authors hypothesized that the mechanism underlying this is transfer of ephedrine across the placenta and stimulation of metabolism in the fetus. METHODS: A total of 104 women having elective Cesarean delivery under spinal anesthesia randomly received infusion of phenylephrine (100 microg/ml) or ephedrine (8 mg/ml) titrated to maintain systolic blood pressure near baseline. At delivery, maternal arterial, umbilical arterial, and umbilical venous blood samples were taken for measurement of blood gases and plasma concentrations of phenylephrine, ephedrine, lactate, glucose, epinephrine, and norepinephrine. RESULTS: In the ephedrine group, umbilical arterial and umbilical venous pH and base excess were lower, whereas umbilical arterial and umbilical venous plasma concentrations of lactate, glucose, epinephrine, and norepinephrine were greater. Umbilical arterial Pco2 and umbilical venous Po2 were greater in the ephedrine group. Placental transfer was greater for ephedrine (median umbilical venous/maternal arterial plasma concentration ratio 1.13 vs. 0.17). The umbilical arterial/umbilical venous plasma concentration ratio was greater for ephedrine (median 0.83 vs. 0.71). CONCLUSIONS: Ephedrine crosses the placenta to a greater extent and undergoes less early metabolism and/or redistribution in the fetus compared with phenylephrine. The associated increased fetal concentrations of lactate, glucose, and catecholamines support the hypothesis that depression of fetal pH and base excess with ephedrine is related to metabolic effects secondary to stimulation of fetal beta-adrenergic receptors. Despite historical evidence suggesting uteroplacental blood flow may be better maintained with ephedrine, the overall effect of the vasopressors on fetal oxygen supply and demand balance may favor phenylephrine.
Authors:
Warwick D Ngan Kee; Kim S Khaw; Perpetua E Tan; Floria F Ng; Manoj K Karmakar
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Publication Detail:
Type:  Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Anesthesiology     Volume:  111     ISSN:  1528-1175     ISO Abbreviation:  Anesthesiology     Publication Date:  2009 Sep 
Date Detail:
Created Date:  2009-08-25     Completed Date:  2009-09-17     Revised Date:  2010-04-26    
Medline Journal Info:
Nlm Unique ID:  1300217     Medline TA:  Anesthesiology     Country:  United States    
Other Details:
Languages:  eng     Pagination:  506-12     Citation Subset:  AIM; IM    
Affiliation:
Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong, China. warwick@cuhk.edu.hk
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MeSH Terms
Descriptor/Qualifier:
Adult
Anesthesia, Spinal*
Apgar Score
Biological Markers
Blood Gas Analysis
Blood Glucose / metabolism
Cesarean Section*
Double-Blind Method
Ephedrine / adverse effects*,  blood,  pharmacokinetics*
Female
Fetus / drug effects,  metabolism*
Fluid Therapy
Hemodynamics / drug effects,  physiology
Humans
Infant, Newborn
Lactic Acid / blood
Maternal-Fetal Exchange*
Phenylephrine / adverse effects*,  blood,  pharmacokinetics*
Pregnancy
Vasoconstrictor Agents / adverse effects*,  blood,  pharmacokinetics*
Chemical
Reg. No./Substance:
0/Biological Markers; 0/Blood Glucose; 0/Vasoconstrictor Agents; 299-42-3/Ephedrine; 50-21-5/Lactic Acid; 59-42-7/Phenylephrine
Comments/Corrections
Comment In:
Anesthesiology. 2009 Sep;111(3):470-2   [PMID:  19672174 ]
Anesthesiology. 2010 May;112(5):1287; author reply 1290-4   [PMID:  20418709 ]
Anesthesiology. 2010 May;112(5):1287-8; author reply 1288-94   [PMID:  20418708 ]
Anesthesiology. 2010 May;112(5):1285-7; author reply 1288-94   [PMID:  20418707 ]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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