Rate-related recirculation: the effect of altering blood flow on dialyzer recirculation

Increasing dialyzer blood flow to enhance the efficiency of dialysis has become commonplace. While it is recognized that this procedure may increase recirculation, the resulting extent of recirculation has not previously been examined. We studied 16 patients with various levels of recirculation and found it to average 8.5% at a blood flow of 50 mL/min, 14.9% at 200 mL/min, and 22.5% at 316 mL/min. This rate-related recirculation has a significant impact on dialyzer urea clearance and should be taken into account in the dialysis prescription.