Experimental data regarding the many factors which influence the various intrahepatic vascular resistances are difficult to obtain due to the relatively inaccessible location of the afferent and efferent hepatic blood vessels and, also, to the complex structure of the intrahepatic sinusoidal system. Many investigations of the responses of the hepatic vascular system to vasoactive agents necessarily have been conducted utilizing intact animals, or animals in which the liver remained in situ. Such studies present unusual difficulties of interpretation; firstly, because of the double blood supply from the hepatic artery and the portal vein and, secondly, because of the simultaneous and usually dominant vasomotor responses which occur in the splanchnic and general vascular systems.
One obvious answer to such problems is the complete isolation of the liver from other body influences by excising the organ and maintaining it in a functioning state by means of a perfusion system. Such a preparation
CONDON RE, NYHUS LM, HARKINS HN. Isolated Perfused Bovine LiverResponses to Common Vasoactive Drugs. Arch Surg. 1964;89(4):602-608. doi:10.1001/archsurg.1964.01320040018004