Background Hypothermic machine perfusion (HMP) for preservation led to compelling success for outcomes of renal transplantation. Application of different concentrations of oxygen during renal HMP has not been systematically analyzed. This study investigates the aspects of renal function and morphology in dependence of oxygen concentrations during HMP in a porcine donation after circulatory death model. Methods After 30 min of warm ischemia, porcine kidneys were randomly assigned to preservation for 21 hr by HMP without oxygenation (HMPnoox), oxygenated HMP with air (HMPair), or 100% oxygen (HMPox100%). Afterward, kidneys were reperfused for 2 hr in an ex vivo model for assessment of function and integrity. Results Application of HMPox100% led to significantly increased blood flow during reperfusion compared to HMPnoox. Preservation by HMPox100% led to a doubling of creatinine clearance after 90 and 120 min of reperfusion (13.4 and 12.0 mL/min) compared to preservation by HMPnoox (7.3 and 7.7 mL/min; P=0.01). Oxygenated HMP with air led to results between the two other groups. Fractional excretion of sodium demonstrated a strong tendency of higher values after HMPnoox compared to HMPox100% (P=0.096) and HMPair (P=0.09). Analysis of structural integrity during reperfusion demonstrated significantly higher values of lactate dehydrogenase resembling cell damage (P=0.02), higher values of gamma-glutamyl-transferase (gGT) resembling tubulus injury (P=0.048), and more pronounced tubular dilatation (P=0.02) after HMPnoox compared to HMPox100%. Conclusion The present study demonstrates that application of HMPox100% for kidneys from donations after circulatory death results in better renal function during early reperfusion compared to HMPnoox.

Machine perfusion for preservation led to compelling success for the outcome of renal transplantation. Further refinements of methods to decrease preservation injury remain an issue of high interest. This study investigates functional and morphological aspects of kidneys preserved by subnormothermic (20 °C) machine perfusion (SNTM) compared with oxygenated hypothermic machine perfusion (HMPox) and cold storage (CS) in a donation after circulatory death (DCD) model. After 30 min of warm ischaemia, porcine kidneys were randomly assigned to preservation for 7 h by CS, HMPox or SNTM. Afterwards, kidneys were reperfused for 2 h with autologous blood in vitro for assessment of function and integrity. Application of SNTM for preservation led to significantly higher blood flow and urine output compared with both other groups. SNTM led to a twofold increased creatinine clearance compared with HMPox and 10-fold increased creatinine clearance compared with CS. Structural integrity was best preserved by SNTM. In conclusion, this is the first study on SNTM for kidneys from DCD donors. SNTM seems to be a promising preservation method with the potential to improve functional parameters of kidneys during reperfusion.

Since 1940 albumin has been used worldwide and is widely available commercially since this time. However, a meta-analysis in 1998 challenged the use of albumin and identified a trend toward higher mortality in critically ill patients who had received albumin. Since then, many studies including multicenter randomized controlled trials have been carried out investigating the safety and efficacy of albumin treatment in different patient cohorts. In this context, patient cohorts that benefit from albumin were identified. However, particularly in non-liver patients, the use of albumin remains controversial. In our comprehensive review, we would like to highlight the most important studies in the recent 20 years and therefore offer an evidence-based outlook for the use of albumin for patients treated in the ICU.