Fate of radioactive krypton (Kr85) introduced intravenously in man

Abstract

When a small volume of dissolved Kr85 was rapidly injected into the venous circulation, only about 5% of the injected gas appeared in the systemic arteries. Further, when a similar solution was infused over a 10-minute period, the fraction reaching the systemic arteries was less than 15% of that contained in the pulmonary arterial blood. Because the problem of recirculation was minimized, an infusion of Kr85 was used to measure continually the output of the right ventricle. The values obtained, both at rest and during steady-state exercise, agreed satisfactorily with direct Fick measurements. Although similar comparisons could not be made in the interval when flow was changing, the values measured with the Kr85 method appeared to be of reasonable magnitude. Submitted on September 2, 1958