in dogs receiving a kidney preserved for three days with the hydroxyethyl starch hes perfusate is compared with the albumin hsa perfused kidney in fig1 with hes as part of the perfusate there is a slight elevation of the serum creatine during the first 2 4 days post transplant followed by a rapid return to normal extending the preservation time with this basic perfusate was unsuccessful until the starch was dialized prior to preparation of the perfusate as shown in fig2 the dialyzed starch gave successful preservation although the kidneys exhibited somewhat elevated serum creatinine values seven day preservation of kidneys was accomplished with the hes based perfusate as shown in fig3 five of 17 dogs 30 survived seven day preservation in all 17 dogs none showed signs of endothelial damage thus the hes based perfusate extends the preservation time beyond that which was possible with the hsa perfusate in addition to the hes the perfusate is radically different from other commonly used perfusates chloride has been replaced with the larger molecular weight and less permeable gluconate to suppress hypothermic induced cell swelling adenosine and po 4 are included to stimulate atp syntheses glutathion is added to suppress the loss of glutathione from perfused organs and to act as an antioxidant the k concentration is elevated to 25mm to suppress the loss of intracellular k at hypothermia and po 4 and hepes are used as buffers the role of some of these agents have been shown to be beneficial to kidneys during preservation one hundred grams.