Excess Ventilation in Chronic Obstructive Pulmonary Disease-Heart Failure Overlap Implications for Dyspnea and Exercise Intolerance

Excess Ventilation in Chronic Obstructive Pulmonary Disease-Heart Failure Overlap Implications for Dyspnea and Exercise Intolerance

Author Rocha, Alcides Autor UNIFESP Google Scholar
Arbex, Flavio F. Autor UNIFESP Google Scholar
Sperandio, Priscilla A. Autor UNIFESP Google Scholar
Souza, Aline Autor UNIFESP Google Scholar
Biazzim, Ligia Autor UNIFESP Google Scholar
Mancuso, Frederico Autor UNIFESP Google Scholar
Berton, Danilo C. Google Scholar
Hochhegger, Bruno Google Scholar
Alencar, Maria Clara N. Autor UNIFESP Google Scholar
Nery, Luiz E. Autor UNIFESP Google Scholar
O'Donnell, Denis E. Google Scholar
Neder, J. Alberto Google Scholar
Abstract Rationale: An increased ventilatory response to exertional metabolic demand (high V-E/V-CO2 relationship) is a common finding in patients with coexistent chronic obstructive pulmonary disease and heart failure. Objectives: We aimed to determine the mechanisms underlying high V-E/V-CO2 and its impact on operating lung volumes, dyspnea, and exercise tolerance in these patients. Methods: Twenty-two ex-smokers with combined chronic obstructive pulmonary disease and heart failure with reduced left ventricular ejection fraction undertook, after careful treatment optimization, a progressive cycle exercise test with capillary (c) blood gas collection. Measurements and Main Results: Regardless of the chosen metric (increased V-E-V-CO2 slope, V-E/V-CO2 nadir, or end-exercise V-E/V-CO2), ventilatory inefficiency was closely related to Pc-CO2 (r values from -0.80 to -0.84; P < 0.001) but not dead space/tidal volume ratio. Ten patients consistently maintained exercise Pc-CO2 less than or equal to 35 mm Hg (hypocapnia). These patients had particularly poor ventilatory efficiency compared with patients without hypocapnia (P < 0.05). Despite the lack of between-group differences in spirometry, lung volumes, and left ventricular ejection fraction, patients with hypocapnia had lower resting Pa-CO2 and lung diffusing capacity (P < 0.01). Excessive ventilatory response in this group was associated with higher exertional Pc-O2. The group with hypocapnia, however, had worse mechanical inspiratory constraints and higher dyspnea scores for a given work rate leading to poorer exercise tolerance compared with their counterparts (P < 0.05). Conclusions: Heightened neural drive promoting a ventilatory response beyond that required to overcome an increased "wasted" ventilation led to hypocapnia and poor exercise ventilatory efficiency in chronic obstructive pulmonary disease-heart failure overlap. Excessive ventilation led to better arterial oxygenation but at the expense of earlier critical mechanical constraints and intolerable dyspnea.
Keywords ventilation
exercise
chronic obstructive pulmonary disease
cardiopulmonary exercise test
xmlui.dri2xhtml.METS-1.0.item-coverage New York
Language English
Sponsor Queen's University
Capes, Brazil
Southeastern Ontario Academic Medical Association, Canada
Date 2017
Published in American Journal Of Respiratory And Critical Care Medicine. New York, v. 196, n. 10, p. 1264-1274, 2017.
ISSN 1073-449X (Sherpa/Romeo, impact factor)
Publisher Amer Thoracic Soc
Extent 1264-1274
Origin http://dx.doi.org/10.1164/rccm.201704-0675OC
Access rights Open access Open Access
Type Article
Web of Science ID WOS:000415216500012
URI https://repositorio.unifesp.br/handle/11600/58169

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