Early detection of airway abnormalities in a selected group of population.

Functional data were collected from 5,746 males from a country region, whose ages ranged from 14 to 65 years. Out of this population we excluded a group of 466 males (9%) who had abnormal results of traditional pulmonary function screening tests (FVC less than 80% reference values or FEV1% FVC less than 70%) and chose a group of 1,092 males (19%) with normal values for the above two parameters but with abnormal forced mid-expiratory flow. In randomly selected persons of the second group we found frequency dependent dynamic compliance (100%), abnormal maximum expiratory flow at 25% of vital capacity (98%), increased residual volume (76%), decreased maximum expiratory flow at 50% of vital capacity (67%), and increased closing capacity (57%); on the contrary static complicane and airway resistance were normal. To account for these results we suppose that measurement of forced mid-expiratory flow, abnormal values of which we obtained in practically one fifth of the experimental population, could represent, in agreement with other reports, a suitable screening test for first or early detection of airway abnormalities.