Hepatic uptake and biliary excretion of Indocyanine green and its use in estimation of hepatic blood flow in dogs

Abstract

Indocyanine green when injected intravenously into normal dogs rapidly disappears, after mixing, from the circulation in an initial exponential fashion. This property enables one to calculate its original volume of distribution and its clearance from the circulation. The initial volume of distribution corresponded closely with the circulating plasma volume. Recovery of the dye from surgically created biliary fistulas approached 100% of the injected amounts and averaged 91%. During constant infusion, significant hepatic arteriovenous differences in dye concentrations occurred, making it possible to calculate hepatic clearances, extraction ratios and liver blood flow. The values obtained by the latter method agreed well with those obtained following single injections. The virtually complete hepatic uptake of Indocyanine green, ease of quantitative plasma and biliary determinations and its exponential loss from the circulation with a short half-life provide advantages over previously used substances in evaluating hepatic function and blood flow.