Porszasz, J, Carraro, N, Cao, R et al. (9 more authors) (2018) Effect of tiotropium on spontaneous expiratory flow–volume curves during exercise in GOLD 1-2 COPD. Respiratory Physiology and Neurobiology, 251. pp. 8-15. ISSN 1569-9048
Abstract
This substudy of a large, randomized, controlled trial (NCT01072396) examined tiotropium (18 μg qd) effects on dynamic hyperinflation during constant work rate treadmill exercise. Areas-under-the-spontaneous expiratory flow-volume (SEFV)-curves were compared in 20 COPD patients and 16 age-matched untreated controls, using rectangular area ratio (RAR) between peak intrabreath and end-expiratory flow. Seven patients exhibited SEFV curve concavity with RAR ≤ 0.5 (RARlow) in ≥1 test without tiotropium; (mean ± SD FEV₁: 1.60 ± 0.59 L; 63.4 ± 14.0%predicted). In RAR(low) patients, tiotropium increased end-exercise inspiratory capacity (IC, 2.10 ± 0.05 vs. 1.89 ± 0.05 L, tiotropium vs. placebo; p = 0.045) and RAR (0.57 ± 0.02 vs. 0.53 ± 0.02; p < 0.001). Patients without SEFV curve concavity with RAR > 0.5 (n = 13; RAR(high), had higher screening FEV₁ (2.15 ± 0.47 L; 79.6 ± 10.1%predicted) versus RARlow patients and no difference in end-exercise IC and RAR between tiotropium and placebo (IC: 2.24 ± 0.03 vs. 2.17 ± 0.03 L; RAR: 0.63 ± 0.005 vs. 0.62 ± 0.005). RAR and%predicted IC at peak exercise were positively correlated in RAR(low) patients (R² = 0.43, p = 0.0002).
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2018 Published by Elsevier B.V. This is an author produced version of a paper published in Respiratory Physiology and Neurobiology. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Constant work rate; Dynamic hyperinflation; Expiratory flow limitation; Inspiratory capacity; Rectangular area ratio; Treadmill exercise |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Biological Sciences (Leeds) > School of Biomedical Sciences (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 14 Feb 2018 14:31 |
Last Modified: | 10 Feb 2019 01:38 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.resp.2018.02.006 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:127405 |