Pulse Push/Pull Hemodialysis: In Vitro Study on New Dialysis Modality With Higher Convective Efficiency

Abstract

Midsize molecule retention is related with renal-failure-associated mortality. Here, the authors describe a new dialysis modality, pulse push/pull hemodialysis (PPPHD), which increases convective clearance. Blood and dialysate are circulated by a pulsatile pump, but with pulsatile flow patterns that are 180 degrees out of phase. This causes blood-to-dialysate pressure gradients that oscillate between positive and negative, and which cause consecutive periods of ultrafiltration and backfiltration. The devised PPPHD was compared with conventional high-flux hemodialysis (CHFHD) in terms of solute clearances, albumin loss, and total protein levels. Human plasma containing dissolved uremic marker molecules was used as a blood substitute, and clearances were investigated for blood urea nitrogen, creatinine, vitamin B12, and inulin. Observed clearances were found to be significantly higher for PPPHD by approximately 3-14% for low-molecular-weight solutes, by 47-48% for vitamin B12, and by 38-49% for inulin than for CHFHD. No albumin loss was observed in either of these two study groups. The authors conclude that PPPHD offers a simple straightforward means of enhancing uremic molecule removal by increasing total ultrafiltration volume without the need to infuse replacement fluid.