Development of a Cold Dialysate Regeneration System for Home Hemodialysis

Abstract

Background/Aims: Because longer and/or more frequent dialysis has potential clinical benefits, home hemodialysis (HHD) systems should provide flexible renal replacement therapies. We propose a new cold dialysate regeneration system that requires 10 l per treatment for HHD. Methods: We designed a dialysate regeneration system using cold dialysate and 2 activated carbon columns alternatively switched between adsorption and desorption. Urea adsorption ratios were compared in three different conditions; cold dialysate (5.7°C), normal dialysate (36.8°C), and cold dialysate with washing. In vivo tests (n = 8) were conducted to validate this system. Results: The urea removal ratios were 20.0 ± 1.7% in cold dialysate, 36.0 ± 1.7% in normal dialysate, and 82.5 ± 1.2% in cold dialysate with washing. In animal experiments, the urea reduction ratio was 60.9 ± 6.3%, Kt/V was 1.0 ± 0.2, and serum electrolytes remained stable. Conclusion: The proposed cold dialysate regeneration system using a small volume of dialysate will be useful for HHD.

Mathematical Analysis of the Long-Term Efficacy of Daily Home Hemodialysis Therapy with a Cold Dialysate Regeneration System

“…Previously, we found that the urea adsorption ratio (UAR) of the CDRS was independent of the initial urea concentration but varied with the dialysate flow rate and perfusion time [15] . In that study, we obtained the time-varying UAR of the CDRS at a dialysate flow rate of 300 ml/min experimentally.…”

“…During HD treatment, one column adsorbs toxins, and the other desorbs the toxins in order to maintain the adsorptive efficacy of the CDRS. A more detailed description of the CDRS was presented in our previous paper [15] .…”

“…A column performing one process (either adsorption or desorption) switches to the other process every 30 min. Based on the experimental observations and previous results [15] , the UAR characteristics of a washed column are assumed to be identical to those of a new AC column.…”

“…The AC adsorbs uremic toxins ranging from 60 to 21,500 Da in molecular weight at a temperature near 0 ° C. Unlike the chemical methods mentioned above, this method does not have side effects, but it is difficult to obtain an adequate dialysis dose using this method [13,14] . Therefore, we previously developed an improved system, the cold dialysate regeneration system (CDRS), to regenerate used dialysate [15] . This system uses two AC columns in parallel.…”

“…To verify this method, the computed results were compared with experimental data on HD with the CDRS for 4 h. Here, the simulation parameters were adopted from our previous experiment [15] . Then, we calculated the delivered dialysis dose using HD with the CDRS and a CHD system for the long term and compared the results of the two systems.…”