The Rationale for Combining Normothermic Liver Machine Perfusion with Continuous Renal Replacement Therapy to Maintain Physiological Perfusate during Ex Vivo Organ Perfusion

: Background: The possibility of keeping liver grafts viable and functioning until transplantation has been explored since the 1950s. However, the current modalities of Normothermic Machine Perfusion (NMP) have shown several limitations, such as the inability to correct electrolytes and pH derangements efficiently. Combining NMP with continuous kidney replacement therapy (CKRT) might provide a promising new model to overcome these issues. Methods: An NMP that covers the organ perfusion, oxygenation, carbon dioxide removal, and thermal balance was connected to a CKRT circuit to ensure physiological hydro-electrolytes, acid-base balance, and catabolite removal from the perfusate. Results: The integration of NMP and CKRT maintains a neoplastic liver in a perfusion system with physiological perfusate for 100 h. CKRT re-established and maintained the hydro-electrolyte and acid-base status throughout the 100 h of perfusion. Significant limitations were the need for frequent monitoring of electrolytes and acid-base disorders and the loss of low molecular weight nutrients, which have to be replenished by manual infusion into the system. Conclusions: This novel CKRT-NMP integrated system may represent a practical and versatile model to support organs' perfusion and extend preservation times. Further experiments are needed to fix monitoring and adjusting processes.