Ventilatory Inefficiency as a Limiting Factor for Exercise in Patients With COPD
| dc.contributor.author | Caviedes, Ivan | |
| dc.contributor.author | Delgado, Iris | |
| dc.contributor.author | Soto, Rodrigo | |
| dc.date.accessioned | 2017-05-24T15:57:01Z | |
| dc.date.available | 2017-05-24T15:57:01Z | |
| dc.date.issued | 2012 | |
| dc.description.abstract | BACKGROUND: Ventilatory inefficiency increases ventilatory demand; corresponds to an abnormal increase in the ratio of minute ventilation (V̇E) to CO2 production (V̇CO2); represents increased dead space, deregulation of respiratory control, and early lactic threshold; and is associated with expiratory flow limitation that enhances dynamic hyperinflation and may limit exercise capacity. OBJECTIVE: To evaluate the influence of ventilatory inefficiency over exercise capacity in COPD patients. METHODS: Prospective study of 35 COPD subjects with different levels of severity, in whom cardiopulmonary stress test was performed. Ventilatory inefficiency was represented by the V̇E/V̇CO2 relation. Its influence over maximal oxygen consumption (V̇O2max), power (W), and ventilatory threshold was evaluated. Surrogate parameters of cardiac function, like oxygen pulse (V̇O2/heart rate) and circulatory power (%V̇O2max × peak systolic pressure), were also evaluated. RESULTS: Cardiopulmonary stress test was stopped due to dyspnea with elevated V̇E and marked reduction of breathing reserve. A severe increase in V̇E/V̇CO2 (mean ± SD 35.9 ± 5.6), a decrease of V̇O2max (mean ± SD 75.2 ± 20%), and a decrease of W (mean ± SD 68.6 ± 23.3%) were demonstrated. Twenty-eight patients presented dynamic hyperinflation. Linear regression showed a reduction of 2.04% on V̇O2max (P < .001), 2.6% on W (P < .001), 1% on V̇O2/heart rate (P = .049), and 322.7 units on circulatory power (P = .02) per each unit of increment in V̇E/V̇CO2, respectively. CONCLUSIONS: Ventilatory inefficiency correlates with a reduction in exercise capacity in COPD patients. Including this parameter in the evaluation of exercise limitation in this patient population may mean a contribution toward the understanding of its pathophysiology. | |
| dc.format.extent | 7 | |
| dc.identifier.citation | Respir Care. 2012 Apr;57(4):583-9 | |
| dc.identifier.uri | http://hdl.handle.net/11447/1310 | |
| dc.identifier.uri | http://dx.doi.org/10.4187/respcare.01342 | |
| dc.language.iso | en_US | |
| dc.publisher | American Association of Respiratory Care | |
| dc.subject | chronic obstructive pulmonary diseases | |
| dc.subject | exercise | |
| dc.subject | Dyspnea | |
| dc.subject | work of breathing | |
| dc.subject | hyperinflation | |
| dc.title | Ventilatory Inefficiency as a Limiting Factor for Exercise in Patients With COPD | |
| dc.type | Artículo |
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