Ex Situ Abdominal Multivisceral Normothermic Machine Perfusion: A Research Protocol

Machine perfusion has revolutionized organ preservation by enabling enhanced graft viability, real-time functional assessment, and targeted therapeutic interventions. However, isolated organ perfusion models may fail to replicate the physiological interplay between abdominal organs. Ex situ multivisceral perfusion offers a promising alternative by maintaining critical inter-organ relationships, potentially improving the viability of low-flow organs, better mimicking in situ physiology, and extending preservation times. This approach may be especially beneficial for multivisceral transplant recipients, who often present with complex clinical needs and limited options. A central challenge in developing multivisceral perfusion strategies is defining and measuring perfusion success. Key indicators include macroscopic graft appearance, hemodynamic and biochemical parameters during perfusion, and post-perfusion histological evaluation. Over the course of perfusion, characteristic changes such as bowel distension and loss of peristalsis may occur, especially during prolonged cases. Successful perfusion is marked by homogeneous graft perfusion, stable arterial flows at physiological pressures, minimal edema, effective lactate clearance, preserved perfusate pH, and sustained bile and urine production without excessive fluid losses. Here, we present a comprehensive, stepwise protocol for normothermic machine perfusion of porcine abdominal multivisceral grafts, designed to support preclinical development and translational efforts aimed at improving organ preservation and expanding the potential of multivisceral transplantation.