Document Detail

Pulmonary hemodynamics and vascular reactivity in asphyxiated term lambs resuscitated with 21 and 100% oxygen.
MedLine Citation:
PMID:  21799125     Owner:  NLM     Status:  MEDLINE    
An increase in oxygen tension is an important factor in decreasing pulmonary vascular resistance (PVR) at birth. Birth asphyxia results in acidosis and increased PVR. We determined the effect of resuscitation with 21 vs. 100% O(2) on pulmonary hemodynamics, pulmonary arterial (PA) reactivity, and oxidant stress in a lamb model of in utero asphyxia. Term fetal lambs were acutely asphyxiated by intrauterine umbilical cord occlusion for 10 min resulting in acidosis (pH 6.96 ± 0.05 and Pco(2) 103 ± 5 Torr), bradycardia, systemic hypotension, and increased PVR. Lambs were treated with 30 min of resuscitation with 21% or 100% O(2) (n = 6 each). Pa(O(2)) was significantly elevated with 100% O(2) resuscitation compared with 21% O(2) (430 ± 38 vs. 64 ± 8 Torr), but changes in pH and Pa(CO(2)) were similar. The 100% O(2) induced greater increase in pulmonary blood flow and decrease in PVR at 1 min of life, but subsequent values were similar to 21% O(2) group between 2 and 30 min of life. Oxygen uptake from the lung and systemic oxygen extraction was similar between the two groups. Pulmonary arteries showed increased staining for superoxide anions and increased contractility to norepinephrine following resuscitation with 100% O(2). The increased PA contractility induced by 100% O(2) was reversed by scavenging superoxide anions with superoxide dismutase and catalase. We conclude that resuscitation of asphyxiated lambs with 100% O(2) increases Pa(O(2)) but does not improve lung oxygen uptake, decrease PVR at 30 min, or increase systemic oxygen extraction ratios. Furthermore, 100% O(2) also induces oxidative stress and increases PA contractility. These findings support the new neonatal resuscitation guidelines recommending 21% O(2) for initial resuscitation of asphyxiated neonates.
Satyan Lakshminrusimha; Robin H Steinhorn; Stephen Wedgwood; Fabio Savorgnan; Jayasree Nair; Bobby Mathew; Sylvia F Gugino; James A Russell; Daniel D Swartz
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2011-07-28
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  111     ISSN:  1522-1601     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2011 Nov 
Date Detail:
Created Date:  2011-11-18     Completed Date:  2012-06-05     Revised Date:  2014-09-18    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1441-7     Citation Subset:  IM    
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MeSH Terms
Animals, Newborn
Asphyxia / drug therapy*,  metabolism,  physiopathology
Catalase / metabolism
Hemodynamics / physiology
Hypertension, Pulmonary / drug therapy,  metabolism,  physiopathology
Lung / blood supply*,  metabolism,  physiopathology
Norepinephrine / metabolism
Oxidative Stress / drug effects,  physiology
Oxygen / administration & dosage*,  metabolism
Pulmonary Artery / metabolism,  physiopathology
Regional Blood Flow / physiology
Resuscitation / methods
Superoxide Dismutase / metabolism
Superoxides / metabolism
Vascular Resistance / physiology
Grant Support
1R03-HD-060138-01/HD/NICHD NIH HHS; 2R01-HL-054705-14/HL/NHLBI NIH HHS; R01 HL054705/HL/NHLBI NIH HHS; R01 HL054705-15/HL/NHLBI NIH HHS
Reg. No./Substance:
11062-77-4/Superoxides; EC; EC Dismutase; S88TT14065/Oxygen; X4W3ENH1CV/Norepinephrine

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

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