Tandem dialyzers with two monitors to meet target KT/V

This preliminary trial was conducted to verify the impact upon delivered KT/V, the percentage change in the urea reduction ratio (%URR), and the frequency of meeting prescribed targets of these parameters of a novel method of combining two dialyzers in series with two monitors in patients with a large body mass or suboptimal vascular access performance. Double dialyzers in parallel are in regular use at our center. Tandem use of dialyzers in series with a single hemodialysis monitor was frustrated by frequent technical difficulties (transmembrane pressure reversal and excessive ultra filtration). We developed a technique of using double dialyzers in series to overcome these technical difficulties with two monitors and limiting all of the ultrafiltration to the second dialyzer. Three patients with A-V grafts and two with catheters had five treatments each with single dialyzers, double dialyzers in parallel, and double dialyzers in series with two monitors after a washout period encompassing the first two sessions in each configuration. Treatment times were set to process exactly 85 L of blood in patients with A-V grafts and 60 L in patients with catheters. The dosages of heparin and ultrafiltration goals were unchanged during the study. In patients with A-V grafts, mean KT/V increased from 1.15 with single dialyzers to 1.35 with double parallel (p < 0.02) and 1.48 with tandem (p < 0.001) dialyzers. %URR (mean) increased from 61.82 for single to 68.32 for double parallel (p < 0.05) and 71.38 (p < 0.001) for tandem dialyzers. Tandem dialyzers with two monitors achieved insignificantly greater %URR and KT/V compared with double parallel dialyzers. The frequency of meeting targets for KT/V improved with double parallel and tandem configurations (p < 0.001). Tandem dialyzers were more frequently successful in delivering target KT/V (p < 0.05) and target %URR (p < 0.001) than double parallel dialyzers. In patients with catheters, neither configuration of double dialyzers succeeded in improving %URR, KT/V, or the frequency with which targets for these parameters were met. Our method of using tandem dialyzers with two monitors is more frequently successful than double parallel dialyzers in enhancing delivered KT/V and %URR in patients with A-V grafts but not catheters as dialysis access.