Document Detail

Effect of changing lung liquid volume on the pulmonary circulation of fetal lambs.
MedLine Citation:
PMID:  3356667     Owner:  NLM     Status:  MEDLINE    
During fetal life the lung develops as a liquid-filled structure with low blood flow compared with postnatal life. We studied the effects of liquid expansion of the fetal lung by measuring vascular conductance in perfused lungs in situ and arterial diameters in excised lungs of fetal lambs. Pulmonary vascular conductance invariably rose as the lung was deflated from its initial volume; maximal deflation to residual volume increased conductance 122%. With reexpansion, conductance fell progressively, culminating in cessation of flow at lung volumes of twice the initial volume. These changes persisted after vagotomy and thoracic sympathectomy and therefore were mechanical in character. Lung expansion from residual volume initially expanded 300- to 500-micron arteries but compressed arteries greater than 1,500 micron. Further expansion reduced the caliber of all arteries. Thus increasing lung liquid volume progressively constricts the pulmonary circulation in the fetus. Because the fetal pulmonary vascular resistance-lung volume relationship differs from that of the U-shaped form found in adult lungs, concepts based on the adult pulmonary circulation are not appropriate for liquid-filled fetal lungs.
A M Walker; B C Ritchie; T M Adamson; J E Maloney
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  64     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1988 Jan 
Date Detail:
Created Date:  1988-05-13     Completed Date:  1988-05-13     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  61-7     Citation Subset:  IM    
Centre for Early Human Development, Monash Medical Centre, Melbourne, Australia.
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MeSH Terms
Fetus / physiology*
Lung / embryology*,  physiology
Lung Volume Measurements
Pulmonary Circulation*
Vascular Resistance

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

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