Uneven ventilation of normal and diseased lungs studied by an open-circuit method

¹ Department of Medicine, Columbia University, College of Physicians and Surgeons and Cardio-Pulmonary Laboratory, (Columbia University Division), Bellevue Hospital, New York City

The uneven ventilation of the lungs of six normal, four emphysematous and four other subjects was studied by an open-circuit method, using 11% helium in air as the indicator gas. The volume and ventilation of two groups of alveoli, one more and one less ventilated, were assessed in most cases. A new graphic method of dealing with open-circuit mixing data is presented. The results are discussed and compared with those of others. Normal lungs can be said to behave as if about half their volume was half as well ventilated as the rest of the lung. Emphysematous lungs can be said to behave as if three-quarters of the lung was only about one-fifth to one-tenth as well ventilated as the remaining quarter.