title: Hyperinflation in asthma and emphysema. Assessment by pulmonary function testing and computed tomography.
abstract: To assess the role of emphysema on the hyperinflation in chronic asthma, we studied 20 subjects with irreversible airflow limitation. Ten of the subjects had asthma and had never smoked; the other ten were cigarette smokers. Pulmonary function testing and chest computed tomography (CT) scans were performed on all subjects. Emphysema was graded using a score based on the percentage of lung involved on CT scan. There was good inter- and intra-observer agreement for the emphysema scores. The median emphysema score was 0 percent in the nonsmoking group and 10 percent in the smoking group. All smokers with a total lung capacity (TLC) of greater than 120 percent predicted had evidence of emphysema on the CT scan. None of the asthmatic subjects with a TLC greater than 120 percent predicted had emphysema identifiable on CT scan. We conclude that chronic asthma with severe hyperinflation does not result in emphysema.
authors.affiliation: Department of Medicine, University of British Columbia, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Kinsella
authors.forename: N L
authors.initials: NL
authors.lastname: Müller
authors.forename: C
authors.initials: C
authors.lastname: Staples
authors.forename: S
authors.initials: S
authors.lastname: Vedal
authors.forename: M
authors.initials: M
authors.lastname: Chan-Yeung
mesh_terms: D000328:Adult; D000368:Aged; D001249:Asthma / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002908:Chronic Disease; D004646:Emphysema / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012123:Pulmonary Ventilation; D012129:Respiratory Function Tests; D012907:Smoking; D014057:Tomography, X-Ray Computed