Kidney Week

Abstract: FR-PO824

Urea Clearance Modelling Using 300 ml/min of Dialysate Flow

Session Information

• Standard Hemodialysis for ESRD - II
  November 03, 2017 | Location: Hall H, Morial Convention Center
  Abstract Time: 10:00 AM - 10:00 AM

Category: Dialysis

• 601 Standard Hemodialysis for ESRD

Authors

• Leypoldt, J. Ken, None, Menlo Park, California, United States

J. Ken Leypoldt,

• Prichard, Sarah S., Outset Medical, San Jose, California, United States

Sarah S. Prichard,

• Chertow, Glenn Matthew, Stanford University School of Medicine, Palo Alto, California, United States

Glenn Matthew Chertow,

• Alvarez, Luis, None, Menlo Park, California, United States

Luis Alvarez,

Background

High dialysate flow rates (Q_D) of 500-700 mL/min are generally used in the outpatient setting to maximize urea removal in a time efficient manner. Lower dialysate flows of 100-200 mL/min are often employed in critically ill patients and in patients at high risk of dialysis disequilibrium. There are few data describing the use of a mid-rate Q_D (300mL/min) in a modern outpatient dialysis setting. We present urea kinetic modeling of 300 mL/min dialysate flow rates and investigate differential urea clearances between 300 and 500 mL/min Q_D.

Methods

Urea kinetic models were used to predict urea clearances at 300 mL/min dialysate flows. Using the FHN trial group urea model assumptions in combination with published dialyzer characteristics (KoA), a weekly urea concentration profile was obtained. The model was then applied to patients of different weights and volumes of distribution (VOD) at blood flows (Q_B) of 400 mL/min. Finally, a clearance relationship for spKt/V of 300 vs. 500 mL/min Q_D was obtained.

Results

Table 1 shows modelled spKt/V when Q_D is 300mL/min or 500 mL/min at the same Q_B of 400 mL/min. Across VOD, the model demonstrates a Q_D of 300 mL/min results in a predicted spKt/V that meets urea clearance targets. There was a small difference in spKt/V between a Q_D of 300 mL/min and 500 mL/min Q_D. Use of a larger KoA (LKoA) dialyzer and 15 minutes of additional time narrows the spKt/V difference.

Conclusion

A Q_D of 300mL/min can be expected to achieve urea clearance targets. Decreasing dialysate flow rate to 300 mL/min results in a modest, but clinically insignificant, spKt/V difference. For patients with clearance challenges at 500mL/min Q_D, the use of a 300 mL/min Q_D with a larger KoA dialyzer and incremental time can be considered, which may itself allow for lower rates of ultrafiltration and better-tolerated hemodialysis therapy.

Table 1: Calculated spKt/V

*spKt/V

Funding

• Commercial Support –