Abnormalitis in the Distributions of Ventilation-perfusion Ratios and Diffusing Capacity-perfusion Ratios in Three Types of Chronic Obstructive Pulmonary Disease

• Published in: Nihon Kyōbu Shikkan Gakkai zasshi Vol. 34; no. 8; pp. 856 - 863
• Main Authors: Koda, Eiichi, Suzuki, Koichi, Suzuki, Yukio, Aoki, Takuya, Kawai, Akira, Mori, Masaaki, Miyata, Atsushi, Nishio, Kazumi, Yamaguchi, Kazuhiro, Takasugi, Tomoaki
• Format: Journal Article
• Language: Japanese
• Published: Japan The Japanese Respiratory Society 01.08.1996
• Subjects: Aged; Aged, 80 and over; Chronic obstructive pulmonary disease; Diffusing capacity-perfusion ratios; Female; High-resolution CT; Humans; Lung Diseases, Obstructive - classification; Lung Diseases, Obstructive - diagnostic imaging; Lung Diseases, Obstructive - physiopathology; Male; Middle Aged; Pulmonary Diffusing Capacity; Radiographic Image Enhancement; Tomography, X-Ray Computed; Ventilation-Perfusion Ratio; Ventilation-perfusion ratios
• ISSN: 0301-1542; 1883-471X
• DOI: 10.11389/jjrs1963.34.856

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.