Responsiveness of continuous ratings of dyspnea during exercise in patients with COPD.
OBJECTIVE
To examine the responsiveness of a new computerized method for patients to provide continuous ratings of dyspnea during exercise in patients with chronic obstructive pulmonary disease (COPD).


METHODS
In this randomized, double-blind study the effects of an inhaled bronchodilator (BD), albuterol/ipratropium bromide solution, were compared with normal saline (NS) in 30 patients with COPD (age, 66+/-9 yr; forced expiratory volume in 1 s, 48+/-14% pred). At visit 1, patients were familiarized with the cycle ergometer and computer, monitor, and mouse system to provide continuous ratings of dyspnea during exercise. At subsequent visits 2-3 d apart, patients performed pulmonary function tests followed by incremental ramp (15 W.min-1) and, 1 h later, constant work (at 55% of maximal work capacity) exercise tests.


RESULTS
During incremental exercise the slopes of VO2:dyspnea and VE:dyspnea regressions were significantly lower, and patients exercised longer (Delta=0.4 min; P=0.003) with BD therapy compared with NS. During constant work exercise there was a significant reduction in dyspnea at the same exercise duration (5.0+/-2.8 vs 6.2+/-2.8 units on the 0-10 category-ratio scale; P=0.02) and patients exercised longer (Delta=0.9 min; P=0.04) with BD therapy. Changes in lung function at rest did not correlate significantly with changes in dyspnea ratings during exercise.


CONCLUSIONS
Continuous ratings of dyspnea were responsive to inhaled bronchodilator therapy during both incremental and constant work exercise tests in patients with symptomatic COPD.
Mahler
Donald A
DA
Section of Pulmonary & Critical Care Medicine, Dartmouth Medical School, Lebanon, NH 03756-0001, USA. Donald.a.mahler@hitchcock.org
Fierro-Carrion
Gustavo
G
Mejia-Alfaro
Roberto
R
Ward
Joseph
J
Baird
John C
JC
D000368:Aged; D000420:Albuterol / Q000627:therapeutic use; D001993:Bronchodilator Agents / Q000627:therapeutic use*; D003201:Computers; D004311:Double-Blind Method; D004417:Dyspnea / Q000188:drug therapy / Q000503:physiopathology*; D005080:Exercise Test / Q000379:methods*; D005260:Female; D006801:Humans; D009241:Ipratropium / Q000627:therapeutic use; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D029424:Pulmonary Disease, Chronic Obstructive / Q000188:drug therapy / Q000503:physiopathology*; D012129:Respiratory Function Tests / Q000379:methods; D012720:Severity of Illness Index; D013147:Spirometry / Q000295:instrumentation / Q000379:methods; D013997:Time Factors
D001993:Bronchodilator Agents; D009241:Ipratropium; D000420:Albuterol