Abstract: SA-PO069
Regional Citrate Anticoagulation: Going around in Circles!
Session Information
- AKI: Clinical, Outcomes, and Trials - Management
October 26, 2024 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Acute Kidney Injury
- 102 AKI: Clinical, Outcomes, and Trials
Authors
- Chan, Sara Jane, Ministry of Health Holdings Pte Ltd, Singapore, Singapore
- Ghani, Ruzita, Singapore General Hospital Department of Renal Medicine, Singapore, Singapore
- Kaushik, Manish, Singapore General Hospital Department of Renal Medicine, Singapore, Singapore
Introduction
Regional Citrate Anticoagulation (RCA) is widely used during Continuous Kidney Replacement Therapy (CKRT). Adequacy of RCA and efficacy of RCA-CKRT are monitored by post-filter ionized calcium (iCa) and systemic total calcium (TCa), iCa, metabolic and acid-base parameters, respectively.
Case Description
An elderly lady with end stage kidney disease on peritoneal dialysis and endometrial carcinoma with previous hysterectomy was admitted for septic shock secondary to buccal abscess. She commenced RCA-CKRT as per institutional protocol. Her circuit clotted in 15 minutes due to catheter flow issue. On her second circuit, without catheter port reversal, laboratory tests were significant for extremely low post-filter iCa (<0.10 mmol/L: target 0.25-0.40 mmol/L). Systemic TCa and iCa showed a gradual increase over 12 hours, necessitating a progressive reduction in her systemic intravenous Ca replacement to 25% of initial rate. Also, her metabolic acidosis persisted despite uninterrupted CKRT. Access recirculation was suspected, and confirmed (>85% recirculation) with simultaneous measurements of systemic, access, pre-filter and post-filter: urea, TCa, iCa and bicarbonate. Abdominal CT scan revealed tip of left femoral dialysis catheter in the external iliac vein but no vein thrombus or external catheter compression. A longer catheter was inserted in right femoral vein and RCA-CKRT continued uneventfully. The removed catheter demonstrated luminal blood clots.
Discussion
The observations were explained by access recirculation and consequent high citrate accumulation locally (low post-filter iCa; filter acidosis) but without adequate systemic buffer contribution (systemic acidosis). In patients on RCA-CKRT, unexpected extremely low post-filter iCa or increasing systemic TCa and iCa requiring decreasing intravenous calcium replacement, should raise suspicion of access recirculation. Improper catheter size and tip position increase risk of recirculation, compromising dialysis delivery despite well anticoagulated functioning filter.
Table: Laboratory parameters and intravenous calcium replacement