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Ventilatory Inefficiency as a Limiting Factor for Exercise in Patients With COPD

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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.identifier.citation Respir Care. 2012 Apr;57(4):583-9 es_CL
dc.identifier.uri http://dx.doi.org/10.4187/respcare.01342 es_CL
dc.identifier.uri http://hdl.handle.net/11447/1310
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. es_CL
dc.format.extent 7 es_CL
dc.language.iso en_US es_CL
dc.publisher American Association of Respiratory Care es_CL
dc.subject chronic obstructive pulmonary diseases es_CL
dc.subject exercise es_CL
dc.subject Dyspnea es_CL
dc.subject work of breathing es_CL
dc.subject hyperinflation es_CL
dc.title Ventilatory Inefficiency as a Limiting Factor for Exercise in Patients With COPD es_CL
dc.type Artículo es_CL


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