Abstract: PO0925
Increasing the Clearance of Protein-Bound Uremic Solutes by Introducing an Activated Carbon Block into the Dialysate Stream
Session Information
- Leveraging Technology and Innovation to Predict Events and Improve Dialysis Delivery
November 04, 2021 | Location: On-Demand, Virtual Only
Abstract Time: 10:00 AM - 12:00 PM
Category: Dialysis
- 701 Dialysis: Hemodialysis and Frequent Dialysis
Authors
- Lee, Seolhyun, Stanford University School of Medicine, Stanford, California, United States
- Sirich, Tammy L., Stanford University School of Medicine, Stanford, California, United States
- Meyer, Timothy W., Stanford University School of Medicine, Stanford, California, United States
Background
The hemodialytic clearance of protein-bound solutes is limited because only the free solute concentration drives diffusion across the membrane. This study tested whether an activated carbon block could reduce accumulation of these solutes in the dialysate and thereby increase their clearance.
Methods
In vitro dialysis of artificial plasma containing urea and the protein-bound solutes p-cresol sulfate (PCS) and indoxyl sulfate (IS) was performed using two dialyzers in series with and without an activated carbon block at the midpoint of the dialysate stream (Figure). Six dialysis experiments were performed each with plasma flow 240 ml/min and dialysate flows of 200 ml/min and 600 ml/min.
Nine additional experiments tested the capacity of the carbon block to take up solutes by measuring solute removal from spent dialysate collected at patient treatments. Spent dialysate was passed through the carbon block at 600 ml/min and fractional removal of solutes was assessed after more than 180 liters had passed through the block.
Results
Use of the carbon block increased the clearances of the tightly bound solutes PCS and IS by 70 ± 13 and 64 ± 19 %, respectively, when the dialysate flow was 200 ml/min. Lesser increases occurred when the dialysate flow was 600 ml/min (PCS 38 ± 5%, IS 33 ± 8%). Urea clearance was unchanged by the carbon block.
The carbon blocks removed 97 ± 4 % of PCS and 96 ± 2 % of IS but only 2 ± 5 % of urea from spent dialysate flowing at 600 ml/min.
Conclusion
Use of a carbon block can increase the clearance of protein-bound solutes particularly at the low dialysate flows often used for home hemodialysis.
Clearances of solutes with or without activated carbon block
| Qd 200 ml/min | Qd 600 ml/min | |||||
| Clearance without carbon (ml/min) | Clearance with carbon (ml/min) | % increase in clearance with vs. without carbon | Clearance without carbon (ml/min) | Clearance with carbon (ml/min) | % increase in clearance with vs. without carbon | |
| Urea | 170 ± 21 | 185 ± 13 | 10 ± 9 | 226 ± 13 | 232 ± 17 | 3 ± 7 |
| PCS | 15 ± 2 | 25 ± 2 | 70 ± 13* | 33 ± 4 | 45 ± 4 | 38 ± 5* |
| IS | 17 ± 3 | 27 ± 3 | 64 ± 19* | 36 ± 4 | 47 ± 5 | 33 ± 8* |
*P <0.01,clearances with vs. without carbon block, Qd = dialysate flow
Funding
- NIDDK Support