Studies of the Ventilation-perfusion Relationships in the Lungs of Subjects with Chronic Pulmonary Emphysema, following a Single Intravenous Injection of Radioactive

The study of the elimination of an inert gas from the lungs of human individuals has proven a useful tool in the determination of ventilation patterns (1, 2). In particular it could be demonstrated that the lungs of emphysematous patients can be conceived as being composed of at least two different compartments, i.e., a relatively small space with good ventilation and a relatively large space with poor ventilation (3). In an attempt to establish the ventilationperfusion relationship in the different lung compartments of patients suffering from pulmonary emphysema, Briscoe (4, 5) correlated the ventilation and volume patterns with the oxygen saturation of mixed arterial blood: a very large and poorly ventilated air compartment in the emphysematous lung was shown to be relatively underperfused with blood (6). In order to check on these findings it was decided to measure the distribution of ventilation and perfusion (especially the latter) in emphysema with an independent technique. Dissolved radioactive krypton (Kr85) was injected intravenously and its rate of disappearance was measured in both expired air and arterial blood. A preliminary report of this work has been published (7). The purpose of this paper is to describe the behavior of intravenously injected krypton in the emphysematous subject and to show how this behavior may be used to determine the distribution of perfusion in the lung. With