ESTIMATION OF RIGHT VENTRICULAR OUTPUT IN MAN USING RADIOACTIVE KRYPTON (Kr85)*

Abstract
A technique is described for the measurement of pulmonary blood flow in man using a constant infusion of Kr85. The theoretical and practical advantages and limitations are discussed and the applicability of the method in steady and changing conditions of cardiac output demonstrated. Blood flow measured by this method and by the direct Fick, both at rest and in a steady state of exercise, agreed within 10% in 24 of 28 determinations. Measurements of blood flow made during the early minutes of exercise, which in 6 of 8 patients was maintained throughout the exercise period.