Document Detail


Effects of hyperoxia on the dynamics of skeletal muscle oxygenation at the onset of heavy-intensity exercise in patients with COPD.
MedLine Citation:
PMID:  20417729     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
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.
Authors:
Ana Cristina B Siqueira; Audrey Borghi-Silva; Daniela M Bravo; Eloara M V Ferreira; Gaspar R Chiappa; J Alberto Neder
Related Documents :
8904579 - Effect of prior o2 breathing on ventilatory response to sustained isocapnic hypoxia in ...
1887519 - Decompression comparison of n2 and o2 in rats.
1548999 - Effect of supramaximal exercise on excess postexercise o2 consumption.
2361889 - Factors affecting whole blood o2 transfer kinetics: implications for theta(o2).
2253719 - Defining the resistance to oxygen transfer in tissue hypoxia.
9809839 - Effects of prolonged bed rest on cardiovascular oxygen transport during submaximal exer...
11606019 - Endurance training under 2500-m hypoxia does not increase myoglobin content in human sk...
22629249 - Effects of physical activity and inactivity on muscle fatigue.
17206929 - Radial versus dorsal ulnar cutaneous sensory studies.
Publication Detail:
Type:  Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-04-24
Journal Detail:
Title:  Respiratory physiology & neurobiology     Volume:  172     ISSN:  1878-1519     ISO Abbreviation:  Respir Physiol Neurobiol     Publication Date:  2010 Jun 
Date Detail:
Created Date:  2010-06-14     Completed Date:  2010-09-17     Revised Date:  2010-10-25    
Medline Journal Info:
Nlm Unique ID:  101140022     Medline TA:  Respir Physiol Neurobiol     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  8-14     Citation Subset:  IM    
Copyright Information:
Copyright 2010 Elsevier B.V. All rights reserved.
Affiliation:
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.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
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

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


Previous Document:  The Respiratory System, second edition.
Next Document:  Gaining insights into the Bcr-Abl activity-independent mechanisms of resistance to imatinib mesylate...