25 October 2025
RESOURCES
Exploring Urea Clearance Measurement in Wearable sorbent-based PD device
Authors
- Arsh Jain, London Health Sciences Centre, London, Ontario, Canada
- Htay Htay, Singapore General Hospital, Singapore
- Edwina A. Brown, Imperial College London, London, England, United Kingdom
- Martin J. Schreiber, Cleveland Clinic, Cleveland, Ohio, United States
- Sheena Gow, Vivance, Singapore
- Jason Tze Chern Lim, Vivance, Singapore
- Sanjay Singh, Vivance, Singapore
- Mandar Gori, Vivance Inc, Los Angeles, California, United States
- Marjorie Wai Yin Foo, Singapore General Hospital, Singapore, Singapore
Background
In recent times, evaluating dialysis adequacy has shifted from a single solute target, i.e. Kt/Vurea, to a more holistic assessment of patients. However, some jurisdictions still mandate Kt/Vurea targets for reimbursement purposes.
Methods
Viva Kompact (VK) is a wearable, sorbent-based PD device. It regenerates 250mL of dialysate at a flow rate of 2L/hr over 56 cycles. The urea removal process in the sorbent during regeneration of dialysate makes it challenging to accurately assess solute removal, making standard PD Kt/Vurea formula of drained dialysate non-representative of the actual dialysis dose delivered. During the pre-pivotal study, VK clearance dynamics was explored – multiple outflow (leaving peritoneum) and inflow samples were taken at Cycle 4, 8, 40 and 54. These were done during full day training sessions and the first day of the 7-day Treatment period.
Results
12 subjects’ data were analysed; 10 male, dialysis vintage: 7-94 months, transport status: 1 High, 7 High A., 3 Low A., 1 Low and 1 anuric. Figure 1 shows urea levels throughout 7 hours of tidal therapy of 50 therapies, averaged across each subject; outflow urea during tidal therapy were lower than in final drain, supporting the notion that using final drain urea in the Kt/Vurea formula would not be representative of tidal clearance. During inflow, urea was mostly at undetected levels(<0.8mmol/L). As such, to cater for differences, it was proposed that tidal clearance be calculated separately from final drain clearance with a modified formula (Figure 2):
Conclusion
This study highlights the need of a modified Kt/Vurea formula for sorbent-based dialysis. While it is still used as a measure of PD efficacy, the quality of PD should be approached holistically, without relying only on small-solute clearances.
Figure 1
Figure 2
Presented at ASN Kidney Week 2025, Houston, TX, Nov 5 – Nov 9, 2025
Copyright © 2025 by the American Society of Nephrology
Published abstract available at: doi: 10.1681/ASN.2025yr2tjx61