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Reduced exercise tolerance in mild chronic obstructive pulmonary disease: The contribution of combined abnormalities of diffusing capacity for carbon monoxide and ventilatory efficiency
Author(s) -
Phillips Devin B.,
James Matthew D.,
Elbehairy Amany F.,
Milne Kathryn M.,
Vincent Sandra G.,
Domnik Nicolle J.,
deTorres Juan P.,
Neder J. Alberto,
O'Donnell Denis E.
Publication year - 2021
Publication title -
respirology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 85
eISSN - 1440-1843
pISSN - 1323-7799
DOI - 10.1111/resp.14045
Subject(s) - dlco , medicine , copd , spirometry , cardiology , diffusing capacity , lung volumes , pulmonary function testing , exercise intolerance , lung , physical therapy , lung function , heart failure , asthma
Background and objective The combination of both reduced resting diffusing capacity of the lung for carbon monoxide (DL CO ) and ventilatory efficiency (increased ventilatory requirement for CO 2 clearance [V˙ E / V˙ CO 2 ]) has been linked to exertional dyspnoea and exercise intolerance in chronic obstructive pulmonary disease (COPD) but the underlying mechanisms are poorly understood. The current study examined if low resting DL CO and higher exercise ventilatory requirements were associated with earlier critical dynamic mechanical constraints, dyspnoea and exercise limitation in patients with mild COPD. Methods In this retrospective analysis, we compared V˙ E / V˙ CO 2 , dynamic inspiratory reserve volume (IRV), dyspnoea and exercise capacity in groups of patients with Global Initiative for Chronic Obstructive Lung Disease stage 1 COPD with (1) a resting DL CO at or greater than the lower limit of normal (≥LLN; Global Lung Function Initiative reference equations [ n = 44]) or (2) below the