Document Detail

Ventilation-perfusion distribution in normal subjects.
MedLine Citation:
PMID:  22773767     Owner:  NLM     Status:  MEDLINE    
Functional values of LogSD of the ventilation distribution (σ(V)) have been reported previously, but functional values of LogSD of the perfusion distribution (σ(q)) and the coefficient of correlation between ventilation and perfusion (ρ) have not been measured in humans. Here, we report values for σ(V), σ(q), and ρ obtained from wash-in data for three gases, helium and two soluble gases, acetylene and dimethyl ether. Normal subjects inspired gas containing the test gases, and the concentrations of the gases at end-expiration during the first 10 breaths were measured with the subjects at rest and at increasing levels of exercise. The regional distribution of ventilation and perfusion was described by a bivariate log-normal distribution with parameters σ(V), σ(q), and ρ, and these parameters were evaluated by matching the values of expired gas concentrations calculated for this distribution to the measured values. Values of cardiac output and LogSD ventilation/perfusion (Va/Q) were obtained. At rest, σ(q) is high (1.08 ± 0.12). With the onset of ventilation, σ(q) decreases to 0.85 ± 0.09 but remains higher than σ(V) (0.43 ± 0.09) at all exercise levels. Rho increases to 0.87 ± 0.07, and the value of LogSD Va/Q for light and moderate exercise is primarily the result of the difference between the magnitudes of σ(q) and σ(V). With known values for the parameters, the bivariate distribution describes the comprehensive distribution of ventilation and perfusion that underlies the distribution of the Va/Q ratio.
Kenneth C Beck; Bruce D Johnson; Thomas P Olson; Theodore A Wilson
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2012-07-05
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  113     ISSN:  1522-1601     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2012 Sep 
Date Detail:
Created Date:  2012-09-17     Completed Date:  2013-02-05     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:  872-7     Citation Subset:  IM    
Department of Internal Medicine, Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, USA.
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MeSH Terms
Acetylene / administration & dosage
Administration, Inhalation
Breath Tests
Cardiac Output
Exercise Test
Helium / administration & dosage
Lung / blood supply*
Methyl Ethers / administration & dosage
Models, Biological
Oxygen / blood*
Pulmonary Circulation*
Pulmonary Ventilation*
Reference Values
Regional Blood Flow
Ventilation-Perfusion Ratio*
Grant Support
Reg. No./Substance:
0/Methyl Ethers; 74-86-2/Acetylene; 7440-59-7/Helium; 7782-44-7/Oxygen; AM13FS69BX/dimethyl ether

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