Heliox Improves Oxygen Delivery and Utilization during Dynamic Exercise in Patients with Chronic Obstructive Pulmonary Disease

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dc.contributor.authorChiappa, Gaspar Rogério da Silva [UNIFESP]
dc.contributor.authorQueiroga, Fernando [UNIFESP]
dc.contributor.authorMeda, Ethiane [UNIFESP]
dc.contributor.authorFerreira, Leonardo Franklin [UNIFESP]
dc.contributor.authorDiefenthaeler, Fernando
dc.contributor.authorNunes, Marcos [UNIFESP]
dc.contributor.authorVaz, Marco A.
dc.contributor.authorMachado, Maria Christina Lombardi Oliveira [UNIFESP]
dc.contributor.authorNery, Luiz Eduardo [UNIFESP]
dc.contributor.authorNeder, Jose Alberto [UNIFESP]
dc.contributor.institutionUniversidade Federal de São Paulo (UNIFESP)
dc.contributor.institutionUniv Kentucky
dc.contributor.institutionUniv Fed Rio Grande do Sul
dc.date.accessioned2016-01-24T13:52:34Z
dc.date.available2016-01-24T13:52:34Z
dc.date.issued2009-06-01
dc.description.abstractRationale: Normoxic heliox (mixture of 79% He and 21% O(2)) may enhance exercise tolerance in patients with chronic obstructive pulmonary disease (COPD). It remains to be determined whether part of these beneficial effects could be ascribed to increased O(2) delivery (O(2)DEL) to locomotor muscles.Objectives: To investigate the effects of heliox on peripheral O(2)DEL and utilization during exercise in moderate to severe COPD.Methods: Twelve mildly hypoxic or nonhypoxemic men (FEV(1) = 45.0 +/- 13.0% predicted) underwent constant-work rate tests (70-80% peak) to the limit of tolerance while receiving heliox or room air. Near-infrared spectroscopy determined changes (Delta) in leg muscle deoxygenation (deoxyhemoglobin concentration [HHb], an index of fractional O(2) extraction), and surface electromyography estimated muscle fiber recruitment (n = 5). Q and Spo(2) were monitored by impedance cardiography and pulse oximetry, respectively.Measurements and Main Results: Heliox significantly decreased dynamic hyperinflation and increased exercise tolerance compared with room air (640 +/- 95 s vs. 371 +/- 100 s; P < 0.01). Heliox also accelerated on-exercise dynamics of (, which were accompanied by faster O(2) uptake kinetics and slower Delta[HHb] responses (P < 0.05). During steady-state exercise, Spo(2)-corrected Delta[HHb] values decreased with heliox despite no significant changes in cardiac output. Muscle fiber recruitment and leg effort scores were also diminished (P < 0.05). On a multiple regression analysis, reductions in dynamic hyperinflation, dyspnea, and Delta[HHb] were independently related to improvements in exercise tolerance with heliox (R(2) = 0.91; p < 0.01).Conclusions: Heliox increases lower limb O(2)DEL and utilization during dynamic exercise in patients with moderate to severe COPD. These effects enhance exercise tolerance in this patient population.en
dc.description.affiliationUniversidade Federal de São Paulo, Dept Med, Div Resp Dis, Pulm Funct & Clin Exercise Physiol Unit SEFICE, BR-04020050 São Paulo, Brazil
dc.description.affiliationUniv Kentucky, Dept Physiol, Lexington, KY USA
dc.description.affiliationUniv Fed Rio Grande do Sul, Sch Phys Educ, Exercise Res Lab, Porto Alegre, RS, Brazil
dc.description.affiliationUnifespUniversidade Federal de São Paulo, Dept Med, Div Resp Dis, Pulm Funct & Clin Exercise Physiol Unit SEFICE, BR-04020050 São Paulo, Brazil
dc.description.sourceWeb of Science
dc.description.sponsorshipPulmonary Function and Clinical Exercise Physiology Unit (Division of Respiratory Diseases, Federal University of São Paulo (UNIFESP), Brazil)
dc.format.extent1004-1010
dc.identifierhttp://dx.doi.org/10.1164/rccm.200811-1793OC
dc.identifier.citationAmerican Journal of Respiratory and Critical Care Medicine. New York: Amer Thoracic Soc, v. 179, n. 11, p. 1004-1010, 2009.
dc.identifier.doi10.1164/rccm.200811-1793OC
dc.identifier.issn1073-449X
dc.identifier.urihttp://repositorio.unifesp.br/handle/11600/31537
dc.identifier.wosWOS:000266509200008
dc.language.isoeng
dc.publisherAmer Thoracic Soc
dc.relation.ispartofAmerican Journal of Respiratory and Critical Care Medicine
dc.rightsAcesso aberto
dc.subjectchronic obstructive pulmonary diseaseen
dc.subjectheliumen
dc.subjectexercise toleranceen
dc.subjectoxygen consumptionen
dc.subjectnear-infrared spectroscopyen
dc.titleHeliox Improves Oxygen Delivery and Utilization during Dynamic Exercise in Patients with Chronic Obstructive Pulmonary Diseaseen
dc.typeArtigo
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