Relation of concavity in the expiratory flow-volume loop to dynamic hyperinflation during exercise in COPD
| Autor: | Richard Casaburi, Shuyi Ma, David W. Hsia, Janos Porszasz, János Varga, Attila Somfay, Ariel Hecht |
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| Rok vydání: | 2016 |
| Předmět: |
Male
Pulmonary and Respiratory Medicine medicine.medical_specialty Time Factors Physiology Expiratory limb Statistics as Topic Incremental exercise Inspiratory Capacity Pulmonary Disease Chronic Obstructive 03 medical and health sciences 0302 clinical medicine Predictive Value of Tests Forced Expiratory Volume Internal medicine medicine Humans Expiration Dynamic hyperinflation Exercise Aged COPD Exercise Tolerance Pulmonary Gas Exchange business.industry General Neuroscience Healthy subjects 030229 sport sciences Middle Aged medicine.disease Respiratory Function Tests Surgery Loop (topology) 030228 respiratory system Exercise Test Cardiology Female business |
| Zdroj: | Respiratory Physiology & Neurobiology. 234:79-84 |
| ISSN: | 1569-9048 |
| DOI: | 10.1016/j.resp.2016.08.005 |
| Popis: | Active expiration during exercise can increase intrathoracic pressure yielding concavity in the expiratory flow-volume loop in COPD. We investigated the relationship between this concavity and dynamic hyperinflation (DH). 17 COPD patients (FEV1: 38 ± 10%pred, GOLD stage 3–4) and 12 healthy subjects performed cycle ergometer incremental exercise. Expiratory limb of the spontaneous flow-volume loop was analyzed breath-by-breath using a geometric approach (rectangular area ratio (RAR), Respir. Med., 104(3):389–96, 2010). RAR below 0.5 demonstrates expiratory limb concavity. DH was determined with serial inspiratory capacity maneuvers. 5 of 17 patients displayed little end-exercise concavity (RAR = 0.52 ± 0.04, group LCONC). 12 patients had concavity at rest and end-exercise RAR reached 0.40 ± 0.03 (group HCONC). Healthy subjects showed no concavity. End-exercise RAR correlated with resting FEV1%pred (R2 = 0.81, P |
| Databáze: | OpenAIRE |
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