Experimental evaluation of the effect of portacaval shunting on ascites requires an animal with simultaneous ascites and normal pressure in the infrahepatic abdominal vena cava. With the use of such a preparation, one may, (a) compare the effects of end-to-side shunting and side-to-side or double barrelled shunts on the course of ascites in large series of animals; and (b) study the pressure and flow phenomena in the different components of the shunts by flowmeter and with radiographic and other techniques. Studies of this type using large enough series of animals to give statistical validity to results, are the only means of resolving the controversies raging over the necessity and indications for "decompressive" shunting, and over the role of the portal vein as an out-flow tract from the congested liver.
While production of ascites due to hepatic outflow obstruction is quite simple and has been done for many years, it is