Renal Oxygenation and Microcirculation in Relation to Fluid Therapy During Kidney Transplantation in a Porcine Model

The Study is ongoing hence no conclusive results can be described The objective of the study is to investigate the renal oxygenation and microcirculation in a high volume fluid therapy against an individualized goal directed fluid therapy (IGDT) during renal transplantation in a porcine model. Background A significant number of kidney recipients experience complications after transplantation ranging from delayed graft function to obstipation and poor wound healing. Iatrogenic over hydration peri‐ and postoperatively is a suspected culprit. Complications are more common in kidneys from brain dead donors. A pilot study showed that the kidney increase in weight and volume after reperfusion due to edema; it is not known if tissue oxygenation is affected by this. Methods The study is a prospective randomized animal study, with four groups: high volume fluid therapy, individualized goal directed fluid therapy each group is subdivided so half receives a low dose norepinephrine. In order to mimic the clinical situation a brain dead donor model is used. Brain death is achieved by raising the intracranial pressure until it exceeds the systolic BP, this is done by inflating a 60 cc urinary catheter epidural. After four hours the kidneys are perfused with “Bridge to life®” cold storage solution and kept on cold ischemia for 18 hours. Two recipient swine have their native kidneys removed and each get one kidney from the donor. After the transplantation the recipients are monitored under anesthesia for ten hours. Fluid responsiveness in the individualized goal directed fluid therapy group is determined by change in stroke volume after fluid challenges. The renal oxygenation and microcirculation are measured using the NF‐BF/OFT/E combined oxygen and the microcirculation probe with the OxyLite™ and OxyFlo™ system from Oxford Optronix. The probes are inserted in the medulla, as it is prone to ischemia if the microcirculatory blood flow is compromised. Results The preliminary results indicate that the renal oxygenation is correlated to urine production, with high oxygen tension in kidneys with high urine production. The fluid therapy does not seem to influence on the oxygenation other than by urine production. The edema seems to equal in the high volume and the individualized fluid therapy. The amount of fluid administered in the individualized group is significantly less than the high volume therapy Preliminary conclusions Invasive measurements of oxygen and microcirculation is a indicator for the metabolic activity in the kidney, from the preliminary results we can se the metabolic oxygen demand is increased in a low volume fluid therapy due to increased reabsorption. Support or Funding Information Novo Nordisk Fondennnfond@novo.dk +45 35276600