Small Airways Disease in Patients without Chronic Air-Flow Limitation

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Abstract
We measured airway diameter and quantitated airway pathology scores in respiratory bronchioles (RB) and membranous bronchioles (MB) in 37 patients undergoing resection for solitary pulmonary nodules. The patients had FEV1 > 75% of the predicted. Measurements of FEV1, nitrogen washout curve (.DELTA.N2/L), closing volume as a percentage of vital capacity (CV/VC%), and maximal flow at 50% of VC (.ovrhdot.V50) were made prior to surgery. There were 22 smokers and 15 nonsmokers. There were more MB per cm2 of tissue than RB (0.74 versus 1.02). The mean internal diameter for MB was 0.55 .+-. 0.27 mm; for RB it was 0.47 .+-. 0.15 mm. There were more MB greater than 1.0 mm in internal diameter than RB greater than 1.0 mm, and the mean diameter of MB was less than that noted in autopsy specimens. The total pathology scores for all airways were less than those found in Caucasian populations. Pathology scores were higher for MB than for RB, except for pigment deposition. Inflammation scores were higher in patients with FEV1 < 100% predicted both for RB (p < 0.05) and for MB (p < 0.05). FEV1, values correlated with goblet cell metaplasia scores (p < 0.05) for MB and with fibrosis (p < 0.05), pigment deposition (p < 0.05), and intraluminal macrophages (p < 0.05) for RB. Tests specifc for small airways (.DELTA.N2/L, .ovrhdot.V50, CV/VC%) di dnot correlate with the pathology scores.