Disease of small airways, with particular reference to lesions found in asymptomatic chronic bronchitis without emphysema.

70S CHEST, VOL. 63, NO. 4, APRIL 1973 SUPPLEMENT Reference to Lesions Found in Asymptomatic Chronic Bronchitis without Emphysema w. M. Thurlbeck, M.D.#{176} W e have measured and counted conducting aimways less than 2 mm in internal diameter ( “small airways” ) in the lungs of patients with and without chronic bronchitis, and with and without emphysema. Eighteen patients without chronic bronchitis or emphysema provided normal values. Lesions were found in 11 patients with chronic bronchitis, but 110 emphysema, all of whom died of other diseases and had no clinical evidence of impaired pulmonary function. These patients showed loss of snlall airways’ lumen ( proportion of lung occupied by lumen of small airways ) , due primarily to narrowing of the airways, likely caused by bmonchiolitis. In addition, about three times as much mucus was present in their small airways as compared to airways of nonbronchitic, nonemphysematous subjects. Small airways’ lumen was also diminished in eight patients with mild, moderate and severe emphysema but no bronchitis and only one of these patients died of obstructive lung disease. In these patients, loss of airways’ lumen was due to loss of airways, as well as airway narrowing. Interestingly, increased mucus was found in the small airways of these subjects when compared to nonbronchitics without emphysema. Twelve patients who had both bronchitis and emphysema and symptomatic ( often fatal ) chronic airways obstruction had loss of airways’ lumen of comparable severity, but had more peripheral mucus plugging. We have also compared lungs fixed via the pulmonary artery to lungs fixed via the bronchus. Lungs fixed and distended via the bronchus have less mucus ill the small airways than do lungs fixed