Novel Extracorporeal Dialysis Circuit to Improve the Removal Efficiency of High and Middle Molecular Weight Toxins.

A new extracorporeal circuit for hemodialysis was designed with the goal of improving the middle and high molecular weight toxins removal. A recirculation pathway was added to the hemodialysis circuit and relevant pressure regulation was performed along the circuit in order to keep the ultrafiltration rate as zero. The influence of increasing the recirculation to dialysate flow rate ratio on the removal of urea, vitamin B12, and hemoglobin was investigated. This removal was also modeled by an analytical method and solved by MATLAB software. A significant increase in removal of vitamin B12 (34%) and especially hemoglobin (228%) was achieved using the recirculation flow in an adjusted hemodialysis circuit. The model showed an acceptable agreement with the experimental results which shows its applicability for prediction of different toxin removal in this circuit.