The morphology and morphometry of small airways disease (relevance to chronic obstructive pulmonary disease).

The morphologic and morphometric characteristics of the small airways of the lung and their relationship to airflow as measured by forced expiratory volume in one second (FEV1) were determined in 37 excised human lungs. After fixation the lungs were graded as to the degree of emphysema and the degree of small airway pathology. The internal diameters of the small airways were measured and corrected for shrinkage during processing. The mean bronchiolar diameter was positively correlated with the % predicted FEV1 (p less than 0.001) and negatively correlated with the small airway fibrosis (p less than 0.01). We conclude that fibrosis of the small airways of the lung is associated with a decrease in airway dimension which is in turn correlated with decreased FEV1 in excised human lungs.