Impaired Carbon Monoxide Diffusing Capacity is the Strongest Predictor of Exercise Intolerance in COPD

Abstract

Diffusing capacity was the strongest predictor of exercise capacity in all subjects. In addition to FEV1, DLCO and IC provided a significantly higher predictive value regarding exercise capacity in COPD patients. This suggests that it is beneficial to add measurements of diffusing capacity and inspiratory capacity when clinically monitoring COPD patients.

Impaired Carbon Monoxide Diffusing Capacity is the strongest lung function predictor of decline in 12 minute-walking distance in COPD; a 5-year follow-up study

“…Furthermore, recent studies suggest that abnormal DLco relates to poorer 6MWD even in ex-smoking subjects without COPD (34). We have also previously reported an association between DLco and peak exercise capacity in patients with COPD, assessed using cycle ergometry (15). Th erefore DLco appears to be an important predictor of exercise capacity, disregarding the type of functional assessment, and together with this consistent predictive value both at baseline and follow-up, implies that DLco provides a more comprehensive understanding of COPD patients' cardiopulmonary limitations, which has also been suggested by other investigators (15,40).…”

“…Mechanistically, a reduced DLco in COPD can refl ect the alveolar-capillary membrane damage subsequent to emphysema (12), increased pressure in the pulmonary circulation (13) or secondary to heart failure (14) and therefore is not necessarily linked to the degree of airway obstruction. A number of publications suggest that DLco is closely linked to impaired exercise capacity, elevated infl ammatory biomarkers and arterial oxygen desaturation in patients with COPD (15)(16)(17). Furthermore, DLco has been found to be an independent predictor of mortality in COPD patients (18).…”

The Determinants of Poor Respiratory Health Status in Adults Living with Human Immunodeficiency Virus Infection

“…42 Moreover, airflow as measured by spirometry likely better reflects the larger, more central airways and may subsequently fail to detect emphysematous changes in the small airways, the site of early disease. Impaired diffusion capacity, on the other hand, could potentially identify more peripheral disease 43 and in fact has been shown to be much more prevalent amongst HIV-infected patients compared to non-HIV-infected patients. 44 Alternatively, our study identified a significant association between health status and CT emphysema scoring, suggesting another possible diagnostic method.…”

A hybrid multibreath wash-in wash-out lung function quantification scheme in human subjects using hyperpolarized3He MRI for simultaneous assessment of specific ventilation, alveolar oxygen tension, oxygen uptake, and air trapping

“…Although there are no established tools to determine the underlying cause of COPD in an individual subject, or to subclassify subjects in clinical studies , a variety of markers have been developed that are sensitive to various aspects of the disease. In addition to the quantitative measures of global airflow restriction (forced expiratory volume in 1 s; FEV 1 and related metrics), measurements of transmembrane gas exchange and qualitative and quantitative evaluations based on x‐ray imaging or computed tomography (CT) have become increasingly popular . Taken together, these tests probe the changes to the lung that are present to varying degrees in all COPD subjects: restricted flow (due to obstruction, airway wall thickening, or altered tissue mechanics), airspace enlargement (emphysema), altered tissue perfusion, alveolar membrane thickening, and air trapping.…”