[Functional-diagnostic criteria of chronic bronchitis].

Basing on the findings gained at investigation of external respiration with measurement of the forced expiration rate in a large group of chronic bronchitis sufferers, subjects exposed to occupational respiratory irritants and in healthy subjects, the conclusion was made on a high informative content in relation to chronic bronchitis diagnosis of a maximal expiration rate at the level of 75% expiratory vital capacity, especially in combination with Tiffeneau test.