WASH-OUT OF THE NON-HEART-BEATING DONOR LIVER: A COMPARISON BETWEEN RINGERS LACTATE, HTK AND POLYSOL

Abstract

P39 Aims: Complete wash-out of the non-heart-beating donor (NHBD) liver during harvest, is of major importance for optimal preservation. The most commonly used wash-out solution when retrieving NHBD livers is histidine tryptophan ketoglutarate (HTK). This solution has a lower viscosity and is less expensive compared to the University of Wisconsin (UW) solution. Machine perfusion (MP) has proven to be beneficial for the preservation of NHBD livers as compared to static, cold storage. A new preservation solution for MP was developed, named Polysol. In previous studies we have shown the superiority of Polysol over UW-Gluconate in MP of rat livers. In order to apply Polysol clinically in NHBD liver retrieval, it will also need to be effective as wash-out solution. The aim of this study is to assess Polysol as a wash-out solution for the NHBD liver and to compare it to HTK and Ringers Lactate (RL). Methods: Male Wistar rats (250-300 g) were used as liver donor. After midline laparotomy and heparinization, phrenotomy was performed to obtain circulatory arrest. After a warm ischemic time (=NHBD time) of 30 minutes the bile duct, portal vein and caval vein were canulated. Thereafter the liver was flushed with 50 cc of either RL, HTK or Polysol through the portal vein, at a pressure of 40 cm H2O. After wash-out, the liver was harvested, weighed and connected to a reperfusion system, using the isolated perfused rat liver (IPRL) system. In the IPRL, the liver was reperfused with normothermic, oxygenated Krebs Henseleit buffer during 60 minutes. During this period, samples were taken to assess hepatocellular injury (AST, ALT and LDH) and liver function (bile production, ammonia clearance, oxygen consumption). The perfusate flow was recorded to calculate intravascular resistance. Liver weight after wash-out was determined as a parameter of fluid extravasation, wet-dry weight ratios were used to determine tissue edema after reperfusion. Results: Hepatocellular damage was significantly increased in the RL group, but there were no differences between the HTK and Polysol groups. Bile production was highest after wash-out with Polysol (395 μl/hour± 34.9) as compared to HTK (311 μl/hour± 11.11) and RL (290 μl/hour± 42.86). Liver weight after flush was less after flush with Polysol (13.5 g± 0.16) as compared to HTK (16.67 g± 0.40) or RL (17.33 g± 0.59) (p<0.005). Overall, no differences were seen in ammonia clearance, oxygen consumption and wet-dry weight ratios after reperfusion. Conclusions: Wash-out of the non-heart-beating donor liver with Polysol results in equal to even better reperfusion results as compared to HTK. Therefore Polysol can be applied as a wash-out solution, as well as a preservation solution for machine perfusion.