Comparative analysis of some methods for standardizing the maximal expiratory flows

Maximal expiratory flows were obtained in 40 patients with chronic non-specific pulmonary diseases displaying mild obstruction of air flows and in 35 clinically healthy subjects with normal ventilatory functions and similar anthropometric characteristics. The flows for the two groups and their standardized values by referring to FVC, TLC, H and H3 were compared. The u-criterion and V% were used as measures for the diagnostic value of the flows and their standardized values. In the patients with mild airflow obstruction the highest u-criterion and the lowest V% were obtained by standardizing the maximal expiratory flows through referring to H3. This is an indication that this method of standardization is to be preferred to other methods in the functional diagnostics of mild obstructive disorders.