LIVER BLOOD FLOW IN PREGNANCY—HEPATIC VEIN CATHETERIZATION 1

Abstract

Numerous liver function tests have been devised and most investigators agree that some disturb- ance in liver function occurs during the toxemias of pregnancy.These changes are of relatively small magnitude and the clinical use of these tests in pregnancy is not widespread.The technique of venous catheterization with resultant sampling of blood directly leaving the liver offers further op- portunities for study of liver function. METHODSA method of estimating hepatic blood flow in man based on the "Fick" principle has been de- scribed by Bradley and coworkers (1).In their article they point out that "The 'Fick' principle may be applied to any organ provided three facts are known: (1) the concentration of some sub- stance, X, in the blood entering the organ, (2) the concentration of X in the mixed venous blood leaving the organ, and (3) the total amount of X removed from the blood by the organ each minute.Given these data, the blood flow through the organ per minute may be calculated by dividing the total removal rate of X by the amount of X removed from each milliliter of blood as it traverses the organ."The removal rate of X by the liver cannot be meas- ured directly, but an indirect method is available if X can be given at such a rate that its blood level remains con- stant.Under these conditions, the infusion rate equals the hepatic removal rate, provided that the extraction of X depends entirely upon hepatic activity.Bromsulfalein (BSP) was used as the test substance since it apparently satisfied these conditions.The calculation of hepatic blood flow then can be de- termined by the following formula: R1 EHEF = 0.01 (P - 1 -Hematocrit