Document Detail

Does correction of exercise-induced desaturation by O(2) always improve exercise tolerance in COPD? A preliminary study.
MedLine Citation:
PMID:  18619828     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: This study sought to investigate whether correction of exercise-induced desaturation by oxygen supply (O(2)) systematically improves exercise tolerance and cardiorespiratory adaptations in COPD patients. METHODOLOGY: Twenty-five COPD patients [FEV(1)=52+/-2.5% pred] exhibiting exercise-induced desaturation performed cyclo-ergometer endurance exercise at 60%of their maximal workload in two randomized conditions: air vs. O(2). O(2) was adjusted to ensure 90 < or = SpO(2) < or = 95%. Endurance time (Tlim), dyspnoea, ventilation (V (E)), breathing frequency (fb), tidal volume (V(T)), cardiac output (CO), heart rate (HR) and arterio-venous difference in oxygen (AVD) were compared between conditions. RESULTS: The comparison of whole group performance between conditions revealed no differences, but individual analysis showed that O(2) increased Tlim for 14 patients [+68%; p<0.01; (positive responders)], decreased it for seven [-36%; p<0.05; (negative responders)] and induced no change for four (non-responders). For positive responders, improved performance was supported by reduced dyspnoea, V (E), fb, HR and CO and increased AVD. For negative responders, hyperoxia resulted in increased dyspnoea and fb without change in V (E) or cardiovascular parameters. CONCLUSION: For comparable correction of exercise desaturation, O(2) does not induce similar effects on exercise responses in all patients. These results were confirmed in complementary study with 11 consecutives patients at higher exercise intensity. For R+, we recorded the classic and expected O(2) effects on cardiorespiratory adaptations (i.e. reduced ventilatory demand and cardiac output). In the other group, exercise breathing frequency and dyspnoea were paradoxically increased despite desaturation correction. However, this study must be considered as pilot study, which will need to be confirmed in future studies conducted on a larger case series.
Nelly Héraud; Christian Préfaut; Fabienne Durand; Alain Varray
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Publication Detail:
Type:  Comparative Study; Journal Article; Randomized Controlled Trial     Date:  2008-07-10
Journal Detail:
Title:  Respiratory medicine     Volume:  102     ISSN:  0954-6111     ISO Abbreviation:  Respir Med     Publication Date:  2008 Sep 
Date Detail:
Created Date:  2008-08-04     Completed Date:  2009-08-14     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8908438     Medline TA:  Respir Med     Country:  England    
Other Details:
Languages:  eng     Pagination:  1276-86     Citation Subset:  IM    
EA 2991, Laboratory of Motor Efficiency and Deficiency, University of Montpellier 1, 700 Av. du Pic Saint Loup, 34090 Montpellier, France.
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MeSH Terms
Analysis of Variance
Cardiac Volume
Exercise Therapy / methods
Exercise Tolerance*
Heart Rate
Lung / physiopathology*
Middle Aged
Oxygen / blood,  therapeutic use*
Oxygen Consumption / physiology
Pulmonary Disease, Chronic Obstructive / blood,  physiopathology*,  therapy
Regression Analysis
Respiratory Function Tests
Stroke Volume
Reg. No./Substance:

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