Experimental Detection of Left-to-Right Circulatory Shunts with Injections of Krypton85

Abstract

Left-to-right shunts were constructed in 8 mongrel dogs by anastomosis of the left subclavian artery to the left pulmonary artery. When solutions of Kr85 were injected into the root of the aorta proximal to a functioning shunt, the Kr85 gas could be detected in the airway by a Geiger-Muller tube in less than 5 seconds. When similar injections were made in the absence of a shunt, the appearance time was usually 10 seconds or more. Thus, by monitoring expired gas it is possible to detect the presence of a shunt resulting in early appearance of Kr85 in pulmonary arterial blood following injection into the left side of the heart or aorta.