Low resting diffusion capacity, dyspnea, and exercise intolerance in chronic obstructive pulmonary disease

摘要

The mechanisms linking reduced diffusing capacity of the lung for carbon monoxide (D-LCO) to dyspnea and exercise intolerance across the chronic obstructive pulmonary disease (COPD) continuum are poorly understood. COPD progression generally involves both D-LCO decline and worsening respiratory mechanics, and their relative contribution to dyspnea has not been determined. In a retrospective analysis of 300 COPD patients who completed symptom-limited incremental cardiopulmonary exercise tests, we tested the association between peak oxygen-uptake (VO2), D-LCO, and other resting physiological measures. Then, we stratified the sample into tertiles of forced expiratory volume in 1 s (FEV1) and inspiratory capacity (IC) and compared dyspnea ratings, pulmonary gas exchange, and respiratory mechanics during exercise in groups with normal and low D-LCO [i.e.,