| Effects of hyperoxia on the dynamics of skeletal muscle oxygenation at the onset of heavy-intensity exercise in patients with COPD. | |
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MedLine Citation:
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PMID: 20417729 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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This study addressed whether hyperoxia (HiOX=50% O2), compared to normoxia, would improve peripheral muscle oxygenation at the onset of supra-gas exchange threshold exercise in patients with chronic obstructive pulmonary disease (COPD) who were not overtly hypoxemic (resting Pa O₂> 60 mmHg ). Despite faster cardiac output and improved blood oxygenation, HiOX did not significantly change pulmonary O2 uptake kinetics ( VO₂p ). Surprisingly, however, HiOX was associated with faster fractional O2 extraction ( approximately Delta[deoxy-Hb+Mb] by near-infrared spectroscopy) (p<0.05). In addition, an "overshoot" in Delta[deoxy-Hb+Mb] was found after the initial fast response only in HiOX (7/11 patients) thereby suggesting impaired intra-muscular O2 delivery ( Q'O ₂mv)-to-utilization. These data indicate that, despite improved "central" O2 delivery, Q'O₂mv adapted at a slower rate than muscle VO₂ under HiOX in non-hypoxaemic patients with COPD. Our results question the rationale of using supplemental O2 to improve muscle oxygenation during the transition to high-intensity exercise in this patient sub-population. |
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Authors:
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Ana Cristina B Siqueira; Audrey Borghi-Silva; Daniela M Bravo; Eloara M V Ferreira; Gaspar R Chiappa; J Alberto Neder |
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Publication Detail:
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Type: Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't Date: 2010-04-24 |
Journal Detail:
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Title: Respiratory physiology & neurobiology Volume: 172 ISSN: 1878-1519 ISO Abbreviation: Respir Physiol Neurobiol Publication Date: 2010 Jun |
Date Detail:
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Created Date: 2010-06-14 Completed Date: 2010-09-17 Revised Date: 2010-10-25 |
Medline Journal Info:
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Nlm Unique ID: 101140022 Medline TA: Respir Physiol Neurobiol Country: Netherlands |
Other Details:
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Languages: eng Pagination: 8-14 Citation Subset: IM |
Copyright Information:
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Copyright 2010 Elsevier B.V. All rights reserved. |
Affiliation:
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Pulmonary Function and Clinical Exercise Physiology Unit (SEFICE), Division of Respiratory Diseases, Department of Medicine, Federal University of Sao Paulo (UNIFESP), Rua Professor Francisco de Castro 54, Vila Clementino, CEP: 04020-050 São Paulo, SP, Brazil. |
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| MeSH Terms | |
Descriptor/Qualifier:
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Aged Cardiac Output / physiology Exercise Therapy / methods* Hemodynamics / physiology Humans Hyperbaric Oxygenation* Male Middle Aged Muscle, Skeletal / physiopathology* Oxygen Consumption / physiology* Physical Endurance / physiology* Pulmonary Disease, Chronic Obstructive / physiopathology, therapy* Pulmonary Gas Exchange Respiratory Function Tests Spectroscopy, Near-Infrared |
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