Document Detail


Regional variations in lung expansion in rabbits: prone vs. supine positions.
MedLine Citation:
PMID:  2793737     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We studied the vertical gradient in lung expansion in rabbits in the prone and supine body positions. Postmortem, we used videomicroscopy to measure the size of surface alveoli through transparent parietal pleural windows at dependent and nondependent sites separated in height by 2-3 cm at functional residual capacity (FRC). We compared the alveolar size measured in situ with that measured in the isolated lungs at different deflationary transpulmonary pressures to obtain transpulmonary pressure (pleural surface pressure) in situ. The vertical gradient in transpulmonary pressure averaged 0.48 +/- 0.16 (SD) cmH2O/cm height (n = 10) in the supine position and 0.022 +/- 0.014 (SD) cmH2O/cm (n = 5) in the prone position. In mechanically ventilated rabbits, we used the rib capsule technique to measure pleural liquid pressure at different heights of the chest in prone and supine positions. At FRC, the vertical gradient in pleural liquid pressure averaged 0.63 cmH2O/cm in the supine position and 0.091 cmH2O/cm in the prone position. The vertical gradients in pleural liquid pressure were all less than the hydrostatic value (1 cmH2O/cm), which indicates that pleural liquid is not generally in hydrostatic equilibrium. Both pleural surface pressure and pleural liquid pressure measurements show a greater vertical gradient in the supine than in the prone position. This suggests a close relationship between pleural surface pressure and pleural liquid pressure. Previous results in the dog and pony showed relatively high vertical gradients in the supine position and relatively small gradients in the prone position. This behavior is similar to the present results in rabbits. Thus the vertical gradient is independent of animal size and might be related to chest shape and weight of heart and abdominal contents.
Authors:
Q H Yang; M R Kaplowitz; S J Lai-Fook
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  67     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1989 Oct 
Date Detail:
Created Date:  1989-11-21     Completed Date:  1989-11-21     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:  1371-6     Citation Subset:  IM; S    
Affiliation:
Biomedical Engineering Center, University of Kentucky, Lexington 40506.
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MeSH Terms
Descriptor/Qualifier:
Animals
Lung / anatomy & histology*
Pleura / physiology
Posture / physiology*
Pressure
Pulmonary Alveoli / anatomy & histology
Rabbits
Regression Analysis
Grant Support
ID/Acronym/Agency:
HL-36597/HL/NHLBI NIH HHS

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


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