ESTIMATION OF PULMONARY ARTERIOVENOUS SHUNT-FLOW USING INTRAVENOUS INJECTIONS OF T-1824 DYE AND KR85*

Abstract

Intravenous injections of Kr85 dissolved in T-1824 dye have been used to estimate abnormal amounts of pulmonary arteriovenous shunt-flow. The method is based on the principle that Kr85, being a poorly soluble gas, will leave the blood perfusing capillaries and enter the alveoli, while that carried by shunts will remain in the bloodstream and thus enter the systemic arteries. By comparing the concentrations of Kr85 to dye in an arterial sample to those in the injected solution, estimates of shunt-flow can be obtained. Application of the method revealed sizeable shunts in 3 patient with Weber-Rendu-Osler''s disease; small shunts in 3 of 12 patients with pulmonary infection; and no shunts in 8 patients with emphysema. Further, in 14 patients with Laennec''s cirrhosis, small shunts were found in 3 and none in the remaining 11. Additional studies on 5 of these patients suggested that vascular anastomoses connected the portal circulation with the pulmonary veins. The studies did not reveal the size of the flow through the anastomoses, nor whether this flow fully accounted for the reduced saturation of the arterial blood.