Measures of small airways disease as predictors of chronic obstructive pulmonary disease

Deficits in FEV1 and FVC have been shown to correlate with the presence of occupationally related obstructive and restrictive lung disease, but significant changes do not occur in the two parameters until these diseases are already well established. The current understanding of the relationship between small airways testing and the subsequent development of COPD is reviewed. Various methods for evaluating peripheral airways are discussed, with emphasis on applicability in the field, reliability and reproducibility, and technical aspects of testing.