Chest
Original ResearchCOPDMeasurement of Dynamic Hyperinflation After a 6-Minute Walk Test in Patients With COPD
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Design
The first 20 patients underwent both a 6MWT and an exercise test with cycle ergometer to allow for the comparison of ICs obtained from both tests (part of their checkup before rehabilitation). Thirty additional patients, who had performed a 6MWT and had undergone additional indirect measures of dyspnea (ie, measurement of the baseline dyspnea index [BDI] and the number of flights of stairs walked), were included in the study (Fig 1).
Patients
Patients with COPD were enrolled consecutively and were
Results
The clinical and functional characteristics of the 50 patients with COPD are described in Table 1. Their median age was 60 years (range, 54 to 69 years), and the median FEV1 was 45% predicted (range, 31% to 67% predicted).
The IC measured with the patient in the standing position (before the 6MWT) tended to be higher than that with the patient in the sitting position for all patients (p = 0.064). The median change in IC during the 6MWT for all patients was −210 mL (range, 55 to −440 mL), whereas
Discussion
The main results of this study are the demonstration that DH can be easily assessed after a 6MWT, correlated to that measured during an incremental exercise test, and correlated to both direct and indirect measures of dyspnea, whereas performance during the 6MWT was mainly related to hyperinflation at rest. Our methodological measurement of IC was different from that adopted by Marin et al.2 In their study, IC was determined using pneumotachography by having the patients inhale while seated.
Acknowledgments
Author contributions: Drs. Callens, Graba, Gillet-Juvin, and Essalhi carried out the measurements of IC at walk, participated in the design of the study, and drafted the manuscript. Dr. Bidaud-Chevalier participated in data collection and helped to draft the manuscript. Drs. Peiffer and Mahut participated in the design, performed the statistical analysis, and helped to draft the manuscript. Dr. Delclaux conceived of the study, performed exercise tests, participated in its design and
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