IT has been hoped that as hepatic and splanchnic hemodynamics were more precisely measured in hepatic cirrhosis with portal hypertension, a rational basis for treatment would evolve. To this end hemodynamic studies have been carried out usually with operative measurements of portal pressure combined with preoperative or postoperative indirect estimations of hepatic blood flow. On the basis of the results of such studies attempts have been made to characterize the diverse patterns of hemodynamic pathology in hepatic cirrhosis, to select the proper operative procedure for a given patient and to gain a better understanding of the postoperative complications that accrue from portal systemic shunting procedures. However, these attempts have been only partially successful. The difficulties of interpreting indirect measurements of hepatic blood flow in cirrhosis and particularly in the individual who has undergone a side-to-side type of portal systemic shunt point up the value of studies with direct measurements of