Transport of K42+, Na24+, and I131+ by the Pulmonary Circulation
Calculations of Cardiac Output and Volume from Dilution Curves Obtained in the Canine Heart-Lung Preparation
The transport of K42+, Na24+, and I131+ by blood through the heart and lungs in the canine heart-lung preparation was studied. Simultaneous injection of each tracer was performed together with nondiffusible Risa as a reference label. The data show that in a single passage through the lung, a fraction of the injected radioactive electrolyte moves out from the blood and partially returns. This alters the shapes of the dilution curves and the results of cardiac output and central volume calculations. The implications of these findings in the suggested use of radioactive electrolytes for the application of the Stew art-Hamilton method in human and animal investigations is discussed. The possibility is suggested that in the Starling preparation, the difference in flows calculated from the extrapolated and complete dilution curves of a non-diffusible tracer may he related to the coronary flow.
- Received March 8, 1961.
- © 1961 American Heart Association, Inc.