title: Physiological and clinical relevance of exercise ventilatory efficiency in COPD.
abstract: Exercise ventilation (V'E) relative to carbon dioxide output (V'CO2) is particularly relevant to patients limited by the respiratory system,e.g.those with chronic obstructive pulmonary disease (COPD). HighV'E-V'CO2(poor ventilatory efficiency) has been found to be a key physiological abnormality in symptomatic patients with largely preserved forced expiratory volume in 1 s (FEV1). Establishing an association between highV'E-V'CO2and exertional dyspnoea in mild COPD provides evidence that exercise intolerance is not a mere consequence of detraining. As the disease evolves, poor ventilatory efficiency might help explaining "out-of-proportion" breathlessness (to FEV1impairment). Regardless, disease severity, cardiocirculatory co-morbidities such as heart failure and pulmonary hypertension have been found to increaseV'E-V'CO2In fact, a highV'E-V'CO2has been found to be a powerful predictor of poor outcome in lung resection surgery. Moreover, a highV'E-V'CO2has added value to resting lung hyperinflation in predicting all-cause and respiratory mortality across the spectrum of COPD severity. Documenting improved ventilatory efficiency after lung transplantation and lung volume reduction surgery provides objective evidence of treatment efficacy. Considering the usefulness of exercise ventilatory efficiency in different clinical scenarios, theV'E-V'CO2relationship should be valued in the interpretation of cardiopulmonary exercise tests in patients with mild-to-end-stage COPD.
authors.affiliation: Respiratory Investigation Unit and Laboratory of Clinical Exercise Physiology, Queen's University and Kingston General Hospital, Kingston, ON, Canada alberto.neder@queensu.ca.
authors.forename: J Alberto
authors.initials: JA
authors.lastname: Neder
authors.affiliation: Respiratory Investigation Unit and Laboratory of Clinical Exercise Physiology, Queen's University and Kingston General Hospital, Kingston, ON, Canada.|Division of Respiratory Medicine, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Danilo C
authors.initials: DC
authors.lastname: Berton
authors.affiliation: Pulmonary Function and Clinical Exercise Physiology, Respiratory Division, Federal University of Sao Paulo, Sao Paulo, Brazil.
authors.forename: Flavio F
authors.initials: FF
authors.lastname: Arbex
authors.affiliation: Division of Cardiology, Federal University of Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Maria Clara
authors.initials: MC
authors.lastname: Alencar
authors.affiliation: Pulmonary Function and Clinical Exercise Physiology, Respiratory Division, Federal University of Sao Paulo, Sao Paulo, Brazil.
authors.forename: Alcides
authors.initials: A
authors.lastname: Rocha
authors.affiliation: Pulmonary Function and Clinical Exercise Physiology, Respiratory Division, Federal University of Sao Paulo, Sao Paulo, Brazil.
authors.forename: Priscila A
authors.initials: PA
authors.lastname: Sperandio
authors.affiliation: Dept of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Palange
authors.affiliation: Respiratory Investigation Unit and Laboratory of Clinical Exercise Physiology, Queen's University and Kingston General Hospital, Kingston, ON, Canada.
authors.forename: Denis E
authors.initials: DE
authors.lastname: O'Donnell
mesh_terms: D002245:Carbon Dioxide; D005080:Exercise Test; D017079:Exercise Tolerance; D005541:Forced Expiratory Volume; D006333:Heart Failure / Q000503:physiopathology; D006801:Humans; D006976:Hypertension, Pulmonary / Q000503:physiopathology; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications* / Q000503:physiopathology*; D011659:Pulmonary Gas Exchange; D012720:Severity of Illness Index
chemical_list: D002245:Carbon Dioxide