title: Evaluation of bronchodilator responses in patients with "irreversible" emphysema.
abstract: Given the emerging physiological and clinical rationale for pharmacological lung-volume reduction, assessment of volume responses to bronchodilators is likely to be highly relevant in chronic obstructive pulmonary disease (COPD). The authors examined the magnitude of lung-volume reduction after acute bronchodilator treatment in patients with advanced emphysema. Eighty-four stable patients with emphysema (mean+/-SEM forced expiratory volume in one second (FEV1): 32+/-1% predicted) performed spirometry and body plethysmography before and 15-30 min after 200 microg salbutamol. Only irreversible patients with a postbronchodilator change in FEV1 <10% pred were considered in this study. Postsalbutamol, the majority of subjects (83%) had significant improvements in one or more lung volumes: on average, residual volume (RV), functional residual capacity (FRC), inspiratory capacity (IC), forced vital capacity and slow vital capacity changed by -18+/-2, -10+/-1, 8+/-1, 9+/-1 and 7+/-1% pred (p<0.0005 each). Total lung capacity (TLC) decreased 0.12+/-0.04 L (p<0.01). Change in IC reflected change in FRC (r=-0.60, p<0.0005), but more strongly in the 57% of patients with no significant change in TLC (r=-0.93, p<0.0005). The magnitude and frequency of volume responses were greatest in patients with the most severe COPD; for example, RV decreased by 0.51+/-0.09 L (23+/-4% pred) and 0.27+/-0.04 L (14+/-2% pred) in severe and moderate subgroups, respectively. Significant reductions in lung hyperinflation occurred in the absence of a change in forced expiratory volume in one second after low-dose salbutamol in a majority of patients with advanced emphysema; the greatest changes occurred in those with the most severe disease.
authors.affiliation: Respiratory Investigation Unit, Dept of Medicine, Queen's University, Kingston, Ontario, Canada.
authors.forename: D E
authors.initials: DE
authors.lastname: O'Donnell
authors.forename: L
authors.initials: L
authors.lastname: Forkert
authors.forename: K A
authors.initials: KA
authors.lastname: Webb
mesh_terms: D000368:Aged; D000420:Albuterol / Q000627:therapeutic use*; D001993:Bronchodilator Agents / Q000627:therapeutic use*; D004646:Emphysema / Q000150:complications / Q000188:drug therapy* / Q000503:physiopathology*; D005260:Female; D005541:Forced Expiratory Volume; D005652:Functional Residual Capacity; D006801:Humans; D007320:Inspiratory Capacity; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications; D012720:Severity of Illness Index; D014109:Total Lung Capacity; D014797:Vital Capacity
chemical_list: D001993:Bronchodilator Agents; D000420:Albuterol