Chest
Volume 94, Issue 2, August 1988, Pages 286-289
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Hyperinflation in Asthma and Emphysema: Assessment by Pulmonary Function Testing and Computed Tomography

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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.

Section snippets

Subjects

Ten patients with asthma who were life-long nonsmokers were studied. The diagnosis of asthma was based on a history of wheezing and/or shortness of breath and presence of variability of air flow obstruction, ie, 20 percent improvement in forced expiratory volume in one second (FEV1) after bronchodilation. They were included in the study if they had asthma for a minimum period of ten years and were more than 45 years of age in an effort to age match them with the chronic smokers. The other ten

RESULTS

The pulmonary function data in the two groups of subjects are summarized in Table 2. There was no statistically significant difference in the level of pulmonary function between the two groups of subjects. The range of total lung capacity (TLC) in the patients with asthma was from 80 percent to 136 percent of predicted. Four of these subjects had a TLC greater than 120 percent of predicted. The range of TLC in the smokers was from 75 percent to 141 percent of predicted. Three of them had a TLC

DISCUSSION

Patients with severe asthma often have persistent hyperinflation between attacks and it is not possible clinically or functionally to separate this group of patients or to rule out associated emphysema. In patients with chronic bronchitis and hyperinflation, the presence of coexisting emphysema is a poor prognostic sign; therefore it is important clinically to assess how much the emphysema contributes to the hyperinflation.

Auerbach et al9 showed that the prevalence of emphysema was much higher

REFERENCES (30)

  • CadeJF et al.

    Pulmonary function during clinical remission of asthma: how reversible is asthma?

    Aust NZ J Med

    (1973)
  • WilliamsDA et al.

    Death from bronchial asthma

    Acta Allergologica

    (1959)
  • AuerbachO et al.

    Relationship of smoking and age to emphysema—whole-lung section study

    N Engl J Med

    (1972)
  • GoughJ

    Post mortem differences in “asthma” and in chronic bronchitis

    Acta Allergologica

    (1961)
  • ThurlbeckWM et al.

    Radiographic appearance of the chest in emphysema

    AJR

    (1978)
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    Manuscript received June 8; revision accepted January 25.

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