Abstract: TH-PO0455
Novel Metric for Predicting Filter Longevity in CRRT Using Post-Filter iCal and Extraction Dynamics
Session Information
- Hemodialysis: Novel Markers and Case Reports
November 06, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Dialysis
- 801 Dialysis: Hemodialysis and Frequent Dialysis
Authors
- Gopireddy, Naga Sumanth Reddy, University of Iowa Hospitals and Clinics, Iowa City, Iowa, United States
- Khawaja, Imran, University of Iowa Hospitals and Clinics, Iowa City, Iowa, United States
- Grover, Sahil, University of Iowa Hospitals and Clinics, Iowa City, Iowa, United States
- Radford, Gwyndolyn Maluki, University of Iowa Hospitals and Clinics, Iowa City, Iowa, United States
- Fraer, Mony, University of Iowa Hospitals and Clinics, Iowa City, Iowa, United States
- Nizar, Jonathan, University of Iowa Hospitals and Clinics, Iowa City, Iowa, United States
- Griffin, Benjamin R., University of Iowa Hospitals and Clinics, Iowa City, Iowa, United States
Background
When using regional citrate anticoagulation (RCA) in continuous kidney replacement therapy (CKRT), maintaining a post-filter ionized calcium (iCa) between 1.0–1.4 mg/dL (0.25-0.35 mmol/L) is recommended to maximize filter life. However, post-filter iCa is affected by factors beyond citrate including systemic calcium levels and effluent flow rate, potentially confounding its interpretation. In this abstract we propose a novel metric of citrate binding that accounts for these factors and evaluate its association with filter life in a cohort of CKRT patients.
Methods
This retrospective single-center study included 161 CKRT filters using RCA from 102 patients admitted from 2022–2024 to the University of Iowa Hospital. Systemic-to-post-filter percent change was calculated by subtracting post-filter iCa from systemic iCa and then dividing by systemic iCa. Extraction percentage was defined as 1 – (blood flow rate (BFR) -Effluent flow rate) / BFR), and the percent change attributable to citrate (PCAC) was the former minus the latter. PCAC was then dichotomized by the median value, and Mann-Whitney U test was used to compare associations with filter life. Binary logistic regression models were used to test for univariable association with filter life dichotomized by the median, and for multivariable association with adjustments for age, gender, comorbidities, and sequential organ failure assessment (SOFA) score.
Results
Filters with PCAC above the median had significantly longer median filter life (38.8 (24.4-61.5) vs 30.4 (20.5–55.9), p<0.001). Univariable logistic regression showed a significant association with filter life above the median (OR 2.30, 95% CI 1.22-4.32) which remained significant after covariate adjustments (OR 2.74, 95% CI 1.34 -5.59). Post-filter ionized calcium was not statistically associated with filter life in this dataset.
Conclusion
While maintaining post-filter iCa in the 1.0–1.4 mg/dL range remains standard, our findings suggest that PCAC is a novel, independent predictor of prolonged filter life that adjusts for systemic calcium and circuit flow conditions, offering a physiologically grounded adjunct to conventional iCa monitoring. Incorporating PCAC alongside post-filter iCa may allow for more individualized, effective RCA strategies in CKRT.