The use of ex-vivo liver perfusion circuit in sheep model: Preliminary report

Objectives: To describe a novel animal model for ex-vivo liver perfusion. Methods: This study was carried out at King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia, between September 2016 and January 2019. We assembled a perfusion circuit operated by a continuous pressure-driven arterial pump with continuous portal and arterial pressure and volume measurements. We used normothermic oxygenated perfusate. The livers used were retrieved from the sheep. Results: Ex-vivo continuous perfusion of the liver was achieved for up to 9 hours with stable pressure and volume in both hepatic artery and portal vein. In 4 experiments the arterial pressure was kept in a range of 48-52 mmHg with a mean of 51.75[+ or -]4.31 resulting in arterial volume at steady state of 223.5[+ or -]48.25 ml/minute (95% confidence level). At steady state the mean portal pressure was 16.25[+ or -]1.45 mmHg with a mean volume of 854[+ or -]313.75 ml/minute (95% confidence level). Bile production was observed during the perfusion period. Hemodynamic parameters were similar to the physiological parameters observed in normothermic perfusion model of the porcine liver. Conclusion: A normothermic oxygenated ex-vivo perfusion circuit was successfully constructed using the sheep liver. A sustainable functional circuit with physiological hemodynamic parameters was achieved. Further study on sheep model seems to be feasible. Keywords: porcine liver, machine perfusion, organ preservation, hepatic flow, animal handling [phrase omitted]