[The "small airways disease" and its early diagnosis]

The "small airways disease" constitutes the initial, silent step of chronic obstructive bronchopneumopathies and remains misknown for a long time. Discussion is made of an anatomic and physiologic definition of these small airways and authors insist on the concept of MEAD's equal pressure point. The classical technics of functional study (spirometry, determination of the resistances in the airways) are of poor help for evidencing the lesions of these airways; more specifical technics have been advanced (flow-volumes curves, frequency-dependence of the compliance...). Their meaning and their place in the detection and diagnosis of chronic obstructive bronchopneumopathies is presently object of numerous discussions.