Abstract
Neither Prefilter Replacement Fluid nor Dialysate Increases Hemoconcentration in Continuous Kidney Replacement Therapy Circuits: FR-PO0189
Journal of the American Society of Nephrology, Vol.36(10S)
10/2025
DOI: 10.1681/ASN.2025s42r80dy
Abstract
Background:
Filter clotting is a major complication of continuous kidney replacement therapy (CKRT) resulting in blood loss, reduced treatment efficacy, and increased cost. Minimization of filtration fraction (FF), an analog for hemoconcentration within a circuit, is often proposed to prolong filter life. However, how best to calculate FF in the setting of pre-filter replacement fluid and dialysate usage is unclear.
Methods:
We prospectively enrolled patients on stable CKRT settings for >24 hours and measured four post-filter hematocrit (HCT) values under varying machine settings to determine hemoconcentration within a circuit, as follows: 1) baseline value, with pre-filter and dialysate flow rates set to zero, 2) total effluent delivered as pre-filter replacement fluid, 3) total effluent delivered as dialysate, and 4) total effluent delivered as post-filter replacement fluid. We allowed at least 10 minutes after changing machine settings before drawing the post-filter HCT, and maintained constant blood flow rate, citrate flow rate, and ultrafiltration rates for all four draws. In patients who were not grossly volume overloaded, ultrafiltration was set to 0 for the duration of the experiment.
Results:
Five of a planned 20 patients have been enrolled to date. Measured post-filter HCT values are given in Table 1. Average percent change from the baseline value, akin to FF attributable to effluent flow rates, was -1.7% for pre-filter replacement fluid, -3.3% for dialysate, and 26.1% for post-filter replacement fluid. Post-filter replacement fluid percent change nicely approximated calculated FF, whereas measured percent change for pre-filter replacement fluid was significantly lower than the calculated value.
Conclusion:
In this prospective study, there was no appreciable hemoconcentration within CKRT circuits due to pre-filter replacement fluid or dialysate. These findings bring into question the accuracy of current FF calculations in settings of predominant pre-filter replacement fluid or dialysate usage.
Details
- Title: Subtitle
- Neither Prefilter Replacement Fluid nor Dialysate Increases Hemoconcentration in Continuous Kidney Replacement Therapy Circuits: FR-PO0189
- Creators
- Gwyndolyn Maluki Radford - University of Iowa Hospitals and Clinics, Iowa City, Iowa, United StatesNaga Sumanth Reddy Gopireddy - University of Iowa Hospitals and ClinicsImran Khawaja - University of Iowa Hospitals and ClinicsSahil Grover - University of Iowa Hospitals and ClinicsJonathan Nizar - University of IowaBenjamin R. Griffin - University of Iowa
- Resource Type
- Abstract
- Publication Details
- Journal of the American Society of Nephrology, Vol.36(10S)
- DOI
- 10.1681/ASN.2025s42r80dy
- ISSN
- 1046-6673
- eISSN
- 1533-3450
- Language
- English
- Date published
- 10/2025
- Academic Unit
- Nephrology; Internal Medicine
- Record Identifier
- 9985019043502771
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