The Japanese journal of thoracic diseases
Online ISSN : 1883-471X
Print ISSN : 0301-1542
ISSN-L : 0301-1542
Abnormalitis in the Distributions of Ventilation-perfusion Ratios and Diffusing Capacity-perfusion Ratios in Three Types of Chronic Obstructive Pulmonary Disease
Kazuhiro YamaguchiMasaaki MoriAkira KawaiTomoaki TakasugiEiichi KodaTakuya AokiKoichi SuzukiAtsushi MiyataKazumi NishioYukio Suzuki
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1996 Volume 34 Issue 8 Pages 856-863

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Abstract
To assess whether diffusion-limited gas exchange plays a significant role in hypoxemia in various types of chronic obstructive pulmonary disease (COPD), we analyzed the distribution of ventilation-perfusion (VA/Q) ratios and of diffusing capacity-perfusion (G/Q) ratios. We compared VA/Q and G/Q distributions in patients with three basic types of COPD: emphysematous changes, bronchiolar involvement, and airway hypersecretion, which were classified based on symptoms and on findings of high-resolution CT. The results were that 1) hypoxemia was not caused by diffusion-limited gas exchange with low G/Q regions in any type of COPD, that 2) hypoxemia in COPD was caused by inhomogeneities in VA/Q distribution, that 3) emphysematous changes and bronchiolar involvement were associated with high and low VA/Q regions, respectively, and that 4) either hypersecretion itself or related airway abnormalities may cause low VA/Q regions to form.
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© by The Japanese Respiratory Society
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