| Bronchodilators accelerate the dynamics of muscle O2 delivery and utilisation during exercise in COPD. | |
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MedLine Citation:
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PMID: 20627914 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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BACKGROUND: Expiratory flow limitation and lung hyperinflation promote cardiocirculatory perturbations that might impair O(2) delivery to locomotor muscles in patients with chronic obstructive pulmonary disease (COPD). The hypothesis that decreases in lung hyperinflation after the inhalation of bronchodilators would improve skeletal muscle oxygenation during exercise was tested. METHODS: Twelve non- or mildly hypoxaemic males (forced expiratory volume in 1 s (FEV(1))=38.5+/-12.9% predicted; Pao(2)>60 mm Hg) underwent constant work rate cycle ergometer exercise tests (70-80% peak) to the limit of tolerance (Tlim) after inhaled bronchodilators (salbutamol plus ipratropium) or placebo. Muscle (de)oxygenation (approximately fractional O(2) extraction) was determined in the vastus lateralis by changes (Delta) in the deoxyhaemoglobin/myoglobin signal ([HHb]) from near-infrared spectroscopy, and cardiac output (QT) was monitored by impedance cardiography. RESULTS: Bronchodilators reduced lung hyperinflation and increased Tlim compared with placebo (454+/-131 s vs 321+/-140 s, respectively; p<0.05). On-exercise kinetics of QT and pulmonary O(2) uptake V(o(2))were accelerated with active treatment; Delta[HHb] dynamics, however, were delayed by approximately 78% and the signal amplitude diminished by approximately 21% (p<0.01). Consequently, the ratio between V(o(2)) and Delta[HHb] dynamics decreased, suggesting improved microvascular O(2) delivery (tau-V(o(2))/MRT-Delta[HHb]=4.48+/-1.57 s vs 2.08+/-1.15 s, p<0.05). Of note, reductions in lung hyperinflation were related to faster QT kinetics and larger decrements in tau-V(o(2))/MRT-Delta[HHb] (p<0.01). CONCLUSIONS: Decreases in operating lung volumes after the inhalation of bronchodilators are associated with faster 'central' cardiovascular adjustments to high-intensity exercise with beneficial consequences on muscle oxygenation in patients with moderate to severe COPD. |
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Authors:
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Danilo C Berton; Priscila B Barbosa; Luciana S Takara; Gaspar R Chiappa; Ana Cristina B Siqueira; Daniela M Bravo; Leonardo F Ferreira; J Alberto Neder |
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Publication Detail:
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Type: Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Thorax Volume: 65 ISSN: 1468-3296 ISO Abbreviation: Thorax Publication Date: 2010 Jul |
Date Detail:
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Created Date: 2010-07-14 Completed Date: 2010-08-05 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0417353 Medline TA: Thorax Country: England |
Other Details:
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Languages: eng Pagination: 588-93 Citation Subset: IM |
Affiliation:
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Pulmonary Function and Clinical Exercise Physiology Unit (SEFICE), Respiratory Division, Department of Medicine, Federal University of São Paulo (UNIFESP), Rua Vila Clementino, São Paulo CEP: 04020-050, Brazil. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adrenergic beta-Agonists
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pharmacology,
therapeutic use Aged Albuterol / pharmacology, therapeutic use Brazil Bronchodilator Agents / pharmacology*, therapeutic use Cholinergic Antagonists / pharmacology, therapeutic use Cross-Over Studies Double-Blind Method Exercise Test / methods Forced Expiratory Volume / drug effects Humans Ipratropium / pharmacology, therapeutic use Leg / physiopathology Male Middle Aged Muscle, Skeletal / physiopathology* Oxygen Consumption / drug effects* Pulmonary Disease, Chronic Obstructive / drug therapy*, physiopathology Vital Capacity / drug effects |
| Chemical | |
Reg. No./Substance:
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0/Adrenergic beta-Agonists; 0/Bronchodilator Agents; 0/Cholinergic Antagonists; 18559-94-9/Albuterol; 60205-81-4/Ipratropium |
| Comments/Corrections | |
Comment In:
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Thorax. 2010 Jul;65(7):573-5
[PMID:
20627910
]
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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