Measurement of portal shunting in dogs

A new method for measuring the quantity of portal blood bypassing the liver (shunted) has been developed and tested in the dog. Shunts were mimicked by the simultaneous infusion of glycocholic acid into a small peripheral portal venule and a peripheral vein. The total infused amount was kept constant, but the ratio at the two infusion sites varied. Determination of the extraction efficiency of the liver by simultaneously measuring the hepatic vein and arterial blood for systemically infused [14C]glycocholic acid permitted the calculation of shunted blood from information provided by the concentration of glycocholic acid in the hepatic vein, artery, and portal vein blood. This method was tested for various proportion of shunting from none to complete. The total hepatic flow was determined with single injection of indocyanine green and the individual arterial and portal vein flows determined with flowmeters. The input ratios of shunting related quite closely to that calculated from the flowmeters or the hepatic extraction ratio.