[New experimental method for analysis of bronchopulmonary airway resistance to airflow (author's transl)]

A modified method from Macklem and Mead, to determine experimentally the central airway resistances to flow (from the trachea to the 6th-8th bronchial branch division) in the dog is described. Performed in vivo and with intact thorax it affords greater physiological conditions, which permit fractionating the value of the total airway resistances in its central and peripheral components. The method was assayed in a pharmacological model of experimental asthma, and in specimens with reversible obstruction of a main pulmonary artery produced by a balloon, and after lobar and bilateral embolism with barium sulphate. The method is selective, reproducible and precise. Its performance is good in 70-80% of cases, and it is, therefore, highly interesting for pharmacological and physiological purposes in the in vivo study of the gross airways in the intact dog.