Studies on the oxygen supply of heterotopic auxiliary liver grafts in rats

Heterotopic auxiliary liver transplantations were performed in rats using the method of Hess et. al. [6]. Oxygen pressure of liver tissue was measured with a Pt-surface electrode of Kessler and Lübbers [10]. After ligation of the hepatic artery, liver tissue PO2 decreased and remained low during further preparation. Only two of the seven lobes of the rat liver (= 30% of the parenchyma) were used as a graft. After revascularization and application of a gelatine plasma substitute, tissue PO2 of the graft increased to values of normal rat liver, although the graft was supplied with portal blood only. We suggest that one reason for this is the increase of portal perfusion rate, for the whole amount of portal blood perfuses only 30% of liver parenchyma. In the first month after transplantation PO2 of the graft parenchyma was low, but increased continually in the following months, reaching PO2 values of normal rat livers after 1 year.