Respiratory care
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Exercise capacity assessed by cardiopulmonary exercise testing is usually measured by peak oxygen consumption (VO2). However, not uncommonly, patients achieve a relatively higher work load (peak work) compared to their peak VO2. In these situations it is difficult to know which parameter to use in assessing exercise capacity. The purpose of this study was to determine whether there are distinguishing physiological characteristics of patients with discordance between percent-of-predicted peak work versus peak VO2, in order to understand how to use these measurements in interpreting exercise capacity. ⋯ The observation that there are distinguishing physiological features between those who have a higher peak work and those who have higher peak VO2 provides insight into the underlying processes determining maximal exercise capacity.
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The diffusion capacity of the lung for carbon monoxide (DLCO) is a good marker of disease severity in patients with idiopathic interstitial pneumonia, and is associated with oxygen saturation; however, little is known about DLCO in systemic sclerosis patients with interstitial lung disease. We studied potential predictors of exercise-induced oxygen desaturation in patients with systemic sclerosis. ⋯ The factor underlying exercise-induced oxygen desaturation appeared to be reduced percent-of-predicted DLCO, which was useful as a predictor in over 80% of the subjects.