Further improvement of circuit survival in citrate based continuous renal replacement therapy.

Background: Continuous renal replacement therapy (CRRT) is the most frequently used modality of renal replacement therapy (RRT) in critical care patients with acute kidney injury (AKI). Adequate CRRT delivery can be challenging, due to problems with circuit patency. To improve circuit patency, we developed a new CRRT protocol using continuous veno-venous hemodiafiltration (CVVHDF) with 3.0 mmol/l regional citrate anticoagulation (CVVHDF/RCA3.0) as our first choice RRT modality.

Methods: Retrospective comparison of efficacy and safety of a CVVHDF/RCA3.0 protocol with our former continuous veno-venous hemofiltration protocol with 2.2 regional citrate anticoagulation (CVVH/RCA2.2) in adult critically ill patients with AKI requiring CRRT between 25 April 2020 and 24 October 2021.

Results: In total, 56 patients (257 circuits) and 66 patients (290 circuits) were included in the CVVH/RCA2.2 and CVVHDF/RCA3.0 groups, respectively. Median circuit survival was significantly higher in patients treated with CVVHDF/RCA3.0 (39.6 (IQR 19.5-67.3) hours) compared to patients treated with CVVH/RCA2.2 (22.9 (IQR 11.3-48.6) hours) (< .001). Higher body weight and higher convective flow were associated with a lower circuit survival. Metabolic control was similar, except for metabolic alkalosis that occurred less frequently during CVVHDF/RCA3.0 (19% of patients) compared to CVVH/RCA2.2 (46% of patients) (= .006).

Conclusions: CRRT circuit survival was longer with CVVHDF/RCA3.0 compared to CVVH/RCA2.2. CRRT circuit survival was negatively associated with higher body weight and higher convective flow.