Measurement of symptoms, lung hyperinflation, and endurance during exercise in chronic obstructive pulmonary disease.
Changes in lung hyperinflation, dyspnea, and exercise endurance are important outcomes in assessing therapeutic responses in chronic obstructive pulmonary disease (COPD). Therefore, we studied the reproducibility of Borg dyspnea ratings, inspiratory capacity (IC; to monitor lung hyperinflation), and endurance time during constant-load symptom-limited cycle exercise in 29 patients with COPD (FEV1 = 40 +/- 2% predicted; mean +/- SEM). Responsiveness was also studied by determining the acute effects of nebulized 500 micrograms ipratropium bromide (IB) or saline placebo (P) on these measurements. During each of four visits conducted over an 8-wk period, spirometry and exercise testing were performed before and 1 h after receiving IB or P (randomized, double-blinded). Highly reproducible measurements included: endurance time (intraclass correlation R = 0.77, p < 0.0001); Borg ratings and IC at rest, at a standardized exercise time (STD), and at peak exercise (R > 0.6, p < 0.0001); and slopes of Borg ratings over time, oxygen consumption (V O2), and ventilation (R > 0.6, p < 0.0001). Responsiveness was confirmed by finding a significant drug effect for: change (Delta) in endurance time (p = 0.0001); DeltaBorgSTD and DeltaBorg-time slopes (p < 0.05); and DeltaIC at rest, at STD, and at peak exercise (p = 0.0001). With all completed visits, DeltaBorgSTD correlated better with DeltaICSTD than any other resting or exercise parameter (n = 115, r = -0.35, p < 0.001). We concluded that Borg dyspnea ratings, and measurements of IC and endurance time during submaximal cycle exercise testing are highly reproducible and responsive to change in severe COPD.
O'Donnell
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Respiratory Investigation Unit, Departments of Medicine, and Community Health and Epidemiology, Queen's University, Kingston, Ontario, Canada. <odonnell@post.queensu.ca>
Lam
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M
Webb
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D000368:Aged; D001993:Bronchodilator Agents / Q000008:administration & dosage / Q000627:therapeutic use; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004417:Dyspnea / Q000188:drug therapy / Q000503:physiopathology*; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D005541:Forced Expiratory Volume / Q000187:drug effects / Q000502:physiology; D006801:Humans; D007320:Inspiratory Capacity / Q000187:drug effects / Q000502:physiology*; D009241:Ipratropium / Q000008:administration & dosage / Q000627:therapeutic use; D008168:Lung / Q000187:drug effects / Q000503:physiopathology*; D008173:Lung Diseases, Obstructive / Q000188:drug therapy / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009330:Nebulizers and Vaporizers; D010101:Oxygen Consumption / Q000187:drug effects / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*; D010919:Placebos; D015203:Reproducibility of Results; D012119:Respiration / Q000187:drug effects; D013147:Spirometry; D016896:Treatment Outcome
D001993:Bronchodilator Agents; D010919:Placebos; D009241:Ipratropium