The impact on the bioenergetic status and oxidative-mediated tissue injury of a combined protocol of hypothermic and normothermic machine perfusion using an acellular haemoglobin-based oxygen carrier: The cold-to-warm machine perfusion of the liver.

INTRODUCTION: The combination of hypothermic and normothermic machine perfusion (HMP+NMP) of the liver provides individual benefits of both techniques, improving the rescue of marginal organs. The aim of this study was to investigate the effect on the bioenergetic status and the oxidative-mediated tissue injury of an uninterrupted combined protocol of HMP+NMP using a single haemoglobin-based oxygen carrier (HBOC)-based perfusate. METHODS: Ten discarded human donor livers had either 2 hours of dual hypothermic oxygenated perfusion (D-HOPE) with sequential controlled rewarming (COR) and then NMP using the HBOC-based perfusate uninterruptedly (cold-to-warm group); or 2 hours of hypothermic oxygenated perfusion (HOPE) with an oxygen carrier-free perfusate, followed by perfusate exchange and then NMP with an HBOC-based perfusate. Markers of liver function, tissue adenosine triphosphate (ATP) levels and tissue injury were systematically assessed. RESULTS: The hypothermic phase downregulated mitochondrial respiration and increased ATP levels in both groups. The cold-to-warm group presented higher arterial vascular resistance during rewarming/NMP (p = 0.03) with a trend of lower arterial flow (p = 0.09). At the end of NMP tissue expression of markers of reactive oxygen species production, oxidative injury and inflammation were comparable between the groups. CONCLUSION: The uninterrupted combined protocol of HMP+NMP using an HBOC-based perfusate-cold-to-warm MP-mitigated the oxidative-mediated tissue injury and enhanced hepatic energy stores, similarly to an interrupted combined protocol; however, it simplified the logistics of this combination and may favour its clinical applicability.

A prospective study investigating the cost effectiveness of intraoperative blood salvage during liver transplantation.

BACKGROUND: Adult orthotopic liver transplantation is associated with significant use of allogenic blood products, which places considerable demands on finite resources. This could be reduced by autologous red cell salvage use, and we evaluated its cost effectiveness in this prospective study. METHODS: Intraoperative autotransfusion was used in 660 adult liver transplant patients between January 1997 and July 2002. These included 134 with acute liver failure, 62 retransplants, 90 alcohol-related, 183 viral, 98 cholestatic chronic liver diseases, and 93 with other etiologies. RESULTS: The total volume of red blood cells transfused was 3641+/-315 ml, 2805+/-234 ml, 2603+/-443 ml, and 2785+/-337 ml for alcohol-related, viral, cholestatic, and others, respectively. Low preoperative hemoglobin was significantly associated with higher intraoperative transfusion requirements. Blood volumes transfused at retransplantation were significantly higher (7077+/-1110 ml vs. 2864+/-138 ml; P<0.001) than for acute liver failure and chronic liver disease. Autologous blood volumes transfused were similar in all diagnostic groups, but were significantly greater in retransplantation (2754+/-541 ml vs. 1524+/-77 ml; P<0.01). Venovenous bypass was significantly associated with higher transfusion requirements. Total savings per case were similar for all diagnostic groups but were greater in cases of retransplantation (864+/-222 pounds (1235+/-317 US dollars) vs. 238+/-24 pounds (340+/-34 US dollars; P<0.001). With the use of autologous transfusion over the study period, a cost saving of 131,901 pounds (188,618 US dollars) was achieved. CONCLUSIONS: Intraoperative red blood cell salvage and autologous transfusion is cost effective in adult liver transplantation. Currently, where optimum resource utilization and fiscal constraint are paramount in healthcare delivery, autologous transfusion is an important adjunct in liver transplantation.