Measurements of total and intrabronchial resistances in normal and diseased isolated lungs.

Postmortem studies of the total lung airways resistance (Rt), the central airways resistance (Rc), and the peripheral airways resistance (Rp) had been performed on normal lungs, on lungs with emphysema and lungs from patients with chronic obstructive pulmonary disease (COPD). In the normal lung a significant relationship between age and Rt was found. A decrease between 20 and 40 yr of age resulted from a decrease of Rp whereas an increase of Rt above the age of 40 was related to an increase in Rp. In the lungs with emphysema and obstruction Rp was increased especially. By variations of the breathing frequency and the lung volume (% of vital capacity) it could be detected that a remarkable effect upon Rt was caused by Rp. In general we found that even in normal lungs Rp is much higher than previously thought.