ASSOCIATION OF HAEMOGLOBIN LEVELS DURING NORMOTHERMIC MACHINE PERFUSION OF PORCINE DONATION AFTER CARDIAC DEATH KIDNEYS WITH RENAL METABOLISM AND FUNCTION

Abstract

Introduction: The shortage of kidneys for transplantation remains. Therefore, kidneys of suboptimal quality are used more often. These derive from expanded criteria donors (ECD) and donation after circulatory death (DCD) donors. Normothermic machine perfusion (NMP) of these marginal donor kidneys is used to preserve and assess renal function. Although perfusion fluids are all based on red blood cells or alternative oxygen carriers, haemoglobin levels are mostly below 6 mmol/L. It is unknown to which extent oxygen carrying capacity is required to support kidney function during NMP. The aim of this study was to retrospectively evaluate the effect of haemoglobin levels on renal metabolism and function during NMP. Methods: Porcine kidneys obtained from a local slaughterhouse were considered eligible for this retrospective cohort study and were included when subjected to a warm ischemic time (WIT) ranging from 30 to 35 minutes and were subsequently preserved with oxygenated hypothermic machine perfusion (HMP) ranging from 3 to 24 hours. For all kidneys a 4 hours observation period with oxygenated NMP with an oxygen carrier was required. Kidneys were stratified according to haemoglobin concentrations (per 1 mmol/L increment). Variables measured were creatinine clearance, oxygen consumption, and fractional sodium reabsorption rates. Results: In total, 101 (84%) of 120 eligible kidneys were included. Preliminary results show that groups containing a haemoglobin level over 5 mmol/L or more result in higher oxygen consumption rates and increased reabsorption of sodium. Creatinine clearance seems to be improved in these groups as well.Conclusion: In this preliminary study, a minimum haemoglobin level of 5 mmol/l seems to be essential to effectively asses renal metabolism and function. It is unclear if lower haemoglobin levels result in renal injury.