A Technique for Measuring Cardiac Output Directly by Cannulation of the Pulmonary Artery

摘要

A method has been devised whereby total cardiac output can be directly and continuously recorded in the anesthetized dog. Such an experimental approach has not hitherto been used. Under anesthesia, the pulmonary artery is exposed and dissected free. A specially devised cannula is inserted into the artery. During cannulation, hemorrhage is avoided either by divertinge th flow through a temporary shunt or by a fibrillation-defibrillation technique which permits a temporary cessation of the circulation. After insertion of the cannula, an optically recording rotameter is attached to it. The output of the right heart passes from the pulmonary artery through the rotameter and is then redistributed to the right and left lungs. This circuit through the rotameter permits a continuous optical recording of total cardiac output. Such procedures have been successful in 9 of 12 dogs, and flows recorded by the rotameter have ranged from 40 cc. to 100 cc. per kilo.