Differential Molecular Modeling Predictions of Mid and Conventional Dialysate Flows.

BACKGROUND: High dialysate flow rates (QD) of 500-800 mL/min are used to maximize urea removal during conventional hemodialysis. There are few data describing hemodialysis with use of mid-rate QD (300 mL/min).

METHODS: We constructed uremic solute (urea, beta2-microglobulin and phosphate) kinetic models at varying volumes of distribution and blood flow rates to predict solute clearances at QD of 300 and 500 mL/min.

RESULTS: Across a range of volumes of distribution a QD of 300 mL/min generally yields a predicted urea spKt/V greater than 1.2 during typical treatment times with a small difference in urea spKt/V between a QD of 300 and 500 mL/min. A larger urea KoA dialyzer and 15 min of additional time narrows the urea spKt/V difference. No substantial differences were observed regarding the kinetics of beta2-microglobulin and phosphate for QD of 300 vs. 500 mL/min.

CONCLUSION: A QD of 300 mL/min can achieve urea clearance targets. Hemodialysis systems using mid-rate QD can be expected to provide adequate hemodialysis, as currently defined.