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Abstract: FR-PO469

Urea Transfer Kinetics in Allo-Hemodialysis: Results from an Ex Vivo Study

Session Information

Category: Dialysis

  • 701 Dialysis: Hemodialysis and Frequent Dialysis

Authors

  • Maheshwari, Vaibhav, Renal Research Institute , New York, New York, United States
  • Grobe, Nadja, Renal Research Institute , New York, New York, United States
  • Tao, Xia, Renal Research Institute , New York, New York, United States
  • Chao, Joshua Emmanuel, Renal Research Institute , New York, New York, United States
  • Thijssen, Stephan, Renal Research Institute , New York, New York, United States
  • Kotanko, Peter, Renal Research Institute , New York, New York, United States

Group or Team Name

  • RRI_alloHD
Background

Allo-hemodialysis (alloHD) is a novel, low-cost extracorporeal dialysis modality where the conventional dialysate is replaced by blood from a healthy subject (“buddy”). We are not aware of literature reporting urea transfer across hemodialyzer membranes with counter-current blood flow through the conventional blood and dialysate compartments.

Methods

We developed a mathematical model of alloHD setup comprising the patient and the buddy beaker, the extracorporeal circuit, and the dialyzer. To calibrate the model, we conducted an ex vivo alloHD experiment with human whole blood. We dialyzed a 500-mL patient bucket against a 500-mL buddy bucket for 60 minutes. Heparin (5,000 U/L) was used as anticoagulant. Average blood flow rate of 110 mL/min on both sides was achieved by peristaltic pumps. The patient side was initially spiked with urea to simulate pre-dialysis conditions. Blood samples from both sides were collected at multiple time-points into the experiment. Serum urea was measured using automated spectrophotometry.

Results

The urea concentrations on the patient and buddy sides equilibrated rapidly (Figure 1). The estimated urea mass transfer coefficient (KoA) was 853 mL/min. Using this estimated KoA, the model-based urea concentrations predicted the observed concentration profiles very well.

Conclusion

The estimated urea KoA of 853 mL/min is similar to a typical urea in vivo KoA reported for conventional hemodialysis (~1000 mL/min). The presence of blood on both sides of the dialyzer membrane did not appear to affect the urea mass transfer capacity of the dialyzer in a clinically meaningful way, and rapid urea equilibrium was achieved in this ex vivo alloHD setup. These findings are an important step towards validation of the alloHD concept and planning of future animal experiments.