DISTRIBUTIONS OF ^<81m>Kr AND PULMONARY RESPONSES AFTER EXERCISE TOLERANCE TEST IN THE ADULY ASTHMATICS

Abstract

In order to assess the presence and severity of EIA in adult asthmatics, ^<81m>Kr inhalation study by bolus method and pulmonary function test were performed on 34 adult asthmatics and 6 normal subjects before and after exercise. Ventilatory abnormalities were detected in 30 out of 34 asthmatics by ^<81m>Kr inhalation study and in 19 out of 32 patients by the pulmonary function test. Patterns of defects on ^<81m>Kr inhalation study were classified into two types, A and B. A type defect: The defect was larger in maximum forced inhalation (MFI) than in static inhalation (SI). B type defect: The defect was larger on the SI than that on he MFI and disappeared when ^<81m>Kr gasses were inhaled at high lung levels. A type defect involves central airway obstruction. In B type defect, there is peripheral airway obstruction and early airway closure is, for the most part, considerable. On the exercise test, sixteen asthmatics ahowed A type dominant, 8 asthmatics showed B type dominant and the 6 asthmatics showed AB type. Exercise-induced changes in FVC after 5 minutes were -3.71±7.77% in the type A dominant group, -17.44±19.92% in the type B dominat group and -15.05±22.06% in the type AB group; and changes in FEV_1.0 were -11.38±11.33%, -20.88±20.55% and -27.66±26.78%, respectively. Percentage changes in FVC and FEV_1.0 were significantly lower in the type B dominant and type AB groups, compared to those in the type A dominant group.