Document Detail


Ventilatory Inefficiency as a Limiting Factor for Exercise in Patients With COPD.
MedLine Citation:
PMID:  22005099     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
OBJECTIVE: Evaluate the influence of ventilatory inefficiency over exercise capacity in COPD patients. Rationale: Ventilatory inefficiency increase ventilatory demand. Corresponds to an abnormal increased in VE/VCO₂ and represents increased dead space, deregulation of respiratory control and early lactic threshold. Associated with expiratory flow limitation enhance DH and may limitate exercise capacity Method: Prospective study of 35 COPD patients with different levels of severity to whom cardiopulmonary stress test (CPET) was performed. Ventilatory inefficiency was represented by VE/VCO₂ relation. Its influence over maximal oxygen consumption (VO₂max), power (W), and ventilatory threshold (AT) were evaluated. Surrogate parameters of cardiac function, like oxygen pulse (VO₂/HR) and circulatory power (CP) = %VO₂max x peak systolic pressure, were also evaluated. RESULTS: CPET was stopped due to dyspnea with elevated minute ventilation (VE) and marked reduction of breathing reserve (BR). A severe increase in VE/VCO₂ (mean: 35.9, SD 5.6), a decrease of VO₂max (mean 75.2%, SD 20) and a decrease of W (mean 68.6%, SD 23.3) were demonstrated. 28 patients presented dynamic hyperinflation (DH). Lineal regression showed a reduction of 2.04% on VO₂max (p<0,001), 2.6% on W (p<0,001), 1% of VO₂/HR (p <0,05), and 322,7 units of CP (p=0,02), per each unit of increment in VE/VCO₂ respectively. CONCLUSION: 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 towards the understanding of its physiopathology.
Authors:
Iván R Caviedes; Iris Delgado; Rodrigo Soto
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-10-13
Journal Detail:
Title:  Respiratory care     Volume:  -     ISSN:  0020-1324     ISO Abbreviation:  -     Publication Date:  2011 Oct 
Date Detail:
Created Date:  2011-10-18     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7510357     Medline TA:  Respir Care     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
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