Abstract
Thirty eight asthmatic patients were studied on pulmonary diffusing capicity for carbon monoxide, history of bronchial asthma, chest X-ray and some of pulmonary function tests. Moreover, pulmonary diffusing capacity among normal subjects was measured and compared to that of asthmatic patients. DLCO was measured by Forster's single breath method modified by Oglivie and CO-workers. Krough's “Permiability” (KCO) was calculated from the same procedure as DLCO.
1) Pulmonary diffusing capacity was found to decrease with advancing age and to increase with increasing either height or alveolar volume. Pulmonary diffusing capacity of asthmatic patients was almost equal to or higher than that of nomal subjects.
2) No significant correlation was found between pulmonary diffusing capacity and FEV 1.0/FVC.
3) Pulmonary diffusing capacity, especially KCO, showed an tendency to decrease with increasing severity of asthma and with advancing emphysematous change in chest X-ray.
4) Asthmatic patients were divided into 2 groups; patients who had asthmatic symptoms since childhood, and patients who had the first experience of asthmatic attacks after adolescence. There was found no significant difference between pulmonary diffusing capacity of these 2 groups. From this result, an impression is given that long-standing bronchial asthma does not necessarily progress to diffuse obstructive emphysema.
5) The more the patients showed severe asthmatic symptoms, the more marked emphysematous changes were proved in chest X-ray of the majority.
6) Pulmonary diffusing capacity was measured among asthmatic patients with history similar to “Tokyo-Yokohama asthma”. No cases showed lowered pulmonary diffusing capacity. This result suggests that there is neither destructive changes as seen in the lung of chronic emphysema nor alveo-capillary block among these patients.
