Document Detail

Partitioning of airway and lung tissue properties: comparison of in situ and open-chest conditions.
MedLine Citation:
PMID:  8567529     Owner:  NLM     Status:  MEDLINE    
The purpose of this study was to investigate under physiological breathing conditions whether airway and lung tissue properties are different in situ and in open-chest conditions. We measured lung input impedance in dogs from 0.2 to 8 Hz with an optimal ventilator waveform at four tidal volumes (VT; from 75 to 450 ml) in intact animals using an esophageal balloon as well as after opening the chest. The lung impedance from both conditions was partitioned into airway and tissue compartments as characterized by airway resistance and inertance (Iaw) and tissue damping (G) and elastance (H) parameters respectively. All parameters except Iaw depended to some extent on VT. The in situ tissue G and H slightly decreased with VT while in the open-chest condition; G decreased and H increased slightly with VT. We found small but significant differences between the mechanical properties of the airway and lung tissues in situ and in open-chest conditions. Over the total population, the G, airway resistance, and Iaw parameters were 13% (not significant), 35% (P < 0.001), and 31% (P < 0.001) smaller, respectively, in situ than in the open-chest condition. However, the H was 15% larger in situ (P < 0.001). Although we cannot completely rule out certain artifacts, these differences most likely reflect real alterations in the lung due to the different configurations and possible differences in the distribution of pleural pressures in the two conditions. The G being smaller and E being larger in situ resulted in hysteresivity (G/H) 36% smaller in situ (P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
B Suki; F Peták; A Adamicza; Z Hantos; K R Lutchen
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  79     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1995 Sep 
Date Detail:
Created Date:  1996-03-07     Completed Date:  1996-03-07     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:  861-9     Citation Subset:  IM    
Department of Biomedical Engineering, Boston University, Massachusetts 02215, USA.
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MeSH Terms
Airway Resistance
Body Composition / physiology*
Electric Impedance
Lung / cytology,  physiology*
Positive-Pressure Respiration
Respiratory Mechanics / physiology*
Grant Support

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