Studies on Hepatic Circulation: Comparison of Trapezoidal Electromagnetic Flowmetry to Clearance Methods with Au¹⁹⁸ Colloid and Indocyanine Green (ICG)

Abstract

It has been acknowledged that variations in results of hepatic flowmetry are quite common according to methods employed. In order to clarify characteristics of the variations it was attempted to compare results of electromagnetic flowmetry to the clearance methods with Au¹⁹⁸ colloid and IGG, using dogs with partial hepatectomies (HX), hepatic arterial ligation (HAL), portal vein constriction (PVC), and end to side portacaval anastomosis (PCA). Before and one hour after the operations measurement of hepatic blood flow (HBF) was performed with trapezoidal electromagnetic flowmeter. Hepatic clearance of Au¹⁹⁸ colloid and ICG was evaluated in terms of K min^-1 (peripheral disappearance rate) and ER (extraction ratio).
Changes of K both of the indicator in each group were almost proportional to that of HBF measured with the flowmeter. This supports the view hitherto held that K is a reliable quantitative index of HBF. In contrast, changes of ER were characteristically different in each group; i.e., increase of ER was observed in 40 per cent HX, PVC, and PCA, and was accompanied with a certain increase of hepatic arterial flow (HAF), however, ER decreased in 70 per cent HX and HAL both accompanying consistent reduction of HAF. These findings indicate that ER is a qualitative index of compensatory function of the liver mainly from hepatic arterial route. It was stated also that K/ER which had been used to caliculate hepatic blood flow in clearance studies was not always proportional to changes of HBF, and therefore this is not suited to represent changes of HBF.