Document Detail

Effect of ventilation and perfusion imbalance on inert gas rebreathing variables.
MedLine Citation:
PMID:  6323367     Owner:  NLM     Status:  MEDLINE    
The effects of ventilation-to-perfusion (VA/Qc) maldistribution within the lungs on measured multiple gas rebreathing variables were studied in 14 dogs. The rebreathing method (using He, C18O, and C2H2) allows for measurements of pulmonary capillary blood flow (Qc), diffusing capacity (DLco), lung gas volume, and the combined pulmonary tissue and capillary blood volume (VTPC). VA/Qc imbalance was created by reversibly occluding the right main pulmonary artery or by reversibly obstructing the left main bronchus in eight dogs. Six additional dogs were ventilated with 10 cmH2O positive end-expiratory pressure (PEEP) to create a bimodal distribution of VA/Qc within the lungs. No significant alterations in computed rebreathing variables, except for a small (14%) decrease in DLco, occurred during right main pulmonary artery occlusion, whereas obstruction of the left main bronchus caused parallel decreases (mean of 46%) in all rebreathing variables. Ventilation with 10 cmH2O PEEP for 3 h caused no alterations in VTPC when compared with postmortem determinations of total lung water. Thus marked alterations in distribution of Qc or creation of VA/Qc maldistributions with PEEP caused no significant changes in rebreathing parameters, whereas obstruction of the left main bronchus resulted in decreases in all rebreathing values consistent with the presumed size of the ventilation defect. Thus it appears that rebreathing estimates of VTPC and other rebreathing parameters are accurate in states of moderate VA/Qc maldistribution within the lung.
M Friedman; S A Wilkins; A F Rothfeld; P A Bromberg
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Publication Detail:
Type:  Journal Article; 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: respiratory, environmental and exercise physiology     Volume:  56     ISSN:  0161-7567     ISO Abbreviation:  J Appl Physiol Respir Environ Exerc Physiol     Publication Date:  1984 Feb 
Date Detail:
Created Date:  1984-05-11     Completed Date:  1984-05-11     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  7801242     Medline TA:  J Appl Physiol Respir Environ Exerc Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  364-9     Citation Subset:  IM; S    
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MeSH Terms
Airway Obstruction / physiopathology
Arterial Occlusive Diseases / physiopathology
Cardiac Output
Dye Dilution Technique
Noble Gases / diagnostic use*
Physiology / methods
Positive-Pressure Respiration
Pulmonary Artery
Pulmonary Edema / diagnosis
Ventilation-Perfusion Ratio*
Grant Support
Reg. No./Substance:
0/Noble Gases

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

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