Regional Citrate Anticoagulation for Continuous Renal Replacement Therapy - A Safe and Effective Low-Dose Protocol

Regional citrate anticoagulation (RCA) is the preferred mode of anticoagulation for continuous renal replacement therapy (CRRT). Conventional RCA-CRRT citrate dose ranges from 3 to 5 mmol/L of blood. This study explored the effectiveness of an RCA protocol with lower citrate dose and its impact on citrate-related complications.

This prospective observational study compared two RCA-CRRT protocols in the intensive care unit. RCA Protocol 1 used an initial citrate dose of 3.0 mmol/L while Protocol 2 started with 2.5 mmol/L. The citrate dose was titrated by sliding scale to target circuit-iCa 0.26-0.40 mmol/L. Calcium was re-infused post-dialyzer and titrated by protocol to target systemic-iCa 1.01-1.20 mmol/L.

Two hundred RCA-CRRT sessions were performed (81 Protocol 1; 119 Protocol 2). The median age was 65.4 years and median APACHE-II score was 23. Citrate dose for Protocol 1 was significantly higher than Protocol 2 in the first 12 h. The circuit clotting rate was similar in both arms (Protocol 1: 9.9%; Protocol 2: 9.2%; P = 0.881). With Protocol 2, circuit-iCa levels were 2.42 times more likely to be on target (P = 0.003) while the odds of hypocalcaemia was 4.67 times higher with Protocol 1 (P < 0.001). There was a wider anion gap was noted with Protocol 1, which suggests a propensity for citrate accumulation with higher citrate exposure.

The RCA protocol with a lower initial citrate dose of 2.5 mmol/L blood had less citrate-related complications with no loss of efficacy. A more precise RCA prescription at the start of treatment avoids unnecessary citrate exposure and improves safety.