(1424) Evaluation of a Regional Citrate Anticoagulation Protocol in Continuous Venovenous Hemodiafiltration

Introduction: Anticoagulation is preferred in continuous renal replacement therapy (CRRT) to prevent filter thrombosis. Regional citrate anticoagulation (RCA) is preferred over systemic heparin, as it extends filter life and reduces bleeding risk but may cause citrate toxicity and requires careful monitoring. This study assessed the efficacy and safety of a nurse-driven RCA protocol using a commercial product in continuous venovenous hemodiafiltration (CVVHDF) patients.

Methods: This single-center, retrospective electronic medical record review evaluated adult patients initiated on RCA for CVVHDF for at least 24 hours from April 2019 to September 2023. Primary outcomes included mean time from initiation of RCA to achieving goal ionized calcium (iCa) in the dialysis circuit and patient, and percent of circuit and patient iCa levels at goal throughout RCA duration. Secondary outcomes included nurse adherence to the lab monitoring schedule and infusion rate adjustments of the protocol and the incidence of citrate toxicity. Cases of potential citrate toxicity were adjudicated independently by two nephrology providers.

Results: A total of 905 encounters were screened and 104 were included in the final analysis. The majority (84.1%) of filters did not need to be changed before 72 hours. Mean time from initiation of RCA to goal circuit iCa was 4.67 hours, and five patients never achieved a goal circuit iCa while on CRRT. Mean time from initiation of calcium infusion to goal patient iCa was 11.2 hours and one patient did not obtain a goal level during their CRRT duration. Overall, desired circuit iCa levels were achieved 58.7% of the time, and desired patient iCa levels were achieved 69.4% of the time. Circuit iCa labs were obtained correctly 73.84% of the time and correct adjustments per protocol were made 65.4% of the time. Patient iCa labs were obtained correctly 75.1% of the time and correct adjustments were made 70.8% of the time. There were zero cases of confirmed citrate toxicity.

Conclusions: Prespecified efficacy and safety margins (≥80%) were not found during review. Due to majority of circuit iCa values being above goal and optimal filter being observed, this could indicate that a wider range of accepted iCa values for circuit anticoagulation may be reasonable.