title: Three-minute constant rate step test for detecting exertional dyspnea relief after bronchodilation in COPD.
abstract: BACKGROUND
  The aim of this study was to evaluate the responsiveness of the 3-minute constant rate step test (3-MST) to detect the relief of exertional dyspnea (respiratory discomfort) after acute bronchodilation in COPD patients.
  
  
  METHODS
  A total of 40 patients with moderate-to-severe COPD (mean forced expiratory volume in 1 second: 45.7 (±14.7), % predicted) performed four 3-MSTs at randomly assigned stepping rates of 14, 16, 20 and 24 steps/min after inhalation of nebulized ipratropium bromide (500 µg)/salbutamol (2.5 mg) and saline placebo, which were randomized to order. Patients rated their intensity of perceived dyspnea at the end of each 3-MST using Borg 0-10 category ratio scale.
  
  
  RESULTS
  A total of 37 (92.5%), 36 (90%), 34 (85%) and 27 (67.5%) patients completed all 3 minutes of exercise at 14, 16, 20 and 24 steps/min under both treatment conditions, respectively. Compared with placebo, ipratropium bromide/salbutamol significantly decreased dyspnea at the end of the third minute of exercise at 14 steps/min (by 0.6±1.0 Borg 0-10 scale units,P<0.01) and 16 steps/min (by 0.7±1.3 Borg 0-10 scale units,P<0.01); however, no statically significant differences were observed between treatments at 20 and 24 steps/min (bothP>0.05).
  
  
  CONCLUSIONS
  The 3-MST, when performed at 14 and 16 steps/min, was responsive to detect the relief of exertional dyspnea after acute bronchodilation in patients with moderate-to-severe COPD.
authors.affiliation: Laboratoire HAVAE, Université de Limoges, Limoges, France; Centre de Recherche, Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec.
authors.forename: Benoit
authors.initials: B
authors.lastname: Borel
authors.affiliation: Clinical Exercise and Respiratory Physiology Laboratory, Department of Kinesiology and Physical Education, McGill University, Montréal, QC.
authors.forename: Courtney A
authors.initials: CA
authors.lastname: Wilkinson-Maitland
authors.affiliation: Boehringer Ingelheim (Canada) Limited, Burlington, ON.
authors.forename: Alan
authors.initials: A
authors.lastname: Hamilton
authors.affiliation: Respiratory Epidemiology and Clinical Research Unit, Montreal Chest Institute, McGill University Health Center, Montreal, QC.
authors.forename: Jean
authors.initials: J
authors.lastname: Bourbeau
authors.affiliation: Faculty of Health Sciences, University of Ottawa, Ottawa, ON.
authors.forename: Hélène
authors.initials: H
authors.lastname: Perrault
authors.affiliation: Clinical Exercise and Respiratory Physiology Laboratory, Department of Kinesiology and Physical Education, McGill University, Montréal, QC; Respiratory Epidemiology and Clinical Research Unit, Montreal Chest Institute, McGill University Health Center, Montreal, QC; Translational Research in Respiratory Diseases Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada.
authors.forename: Dennis
authors.initials: D
authors.lastname: Jensen
authors.affiliation: Centre de Recherche, Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec.
authors.forename: François
authors.initials: F
authors.lastname: Maltais
mesh_terms: D000280:Administration, Inhalation; D058666:Adrenergic beta-2 Receptor Agonists / Q000008:administration & dosage*; D000368:Aged; D000420:Albuterol / Q000008:administration & dosage*; D001993:Bronchodilator Agents / Q000008:administration & dosage*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004417:Dyspnea / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology; D005080:Exercise Test / Q000379:methods*; D017079:Exercise Tolerance; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D009241:Ipratropium / Q000008:administration & dosage*; D008168:Lung / Q000187:drug effects* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D018727:Muscarinic Antagonists / Q000008:administration & dosage*; D009330:Nebulizers and Vaporizers; D011237:Predictive Value of Tests; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology; D011792:Quebec; D020127:Recovery of Function; D012720:Severity of Illness Index; D013997:Time Factors; D016896:Treatment Outcome; D014797:Vital Capacity
chemical_list: D058666:Adrenergic beta-2 Receptor Agonists; D001993:Bronchodilator Agents; D018727:Muscarinic Antagonists; D009241:Ipratropium; D000420:Albuterol
keywords: chronic obstructive pulmonary disease; dyspnea; exercise testing; intervention