Safety and efficacy of citrate anti-coagulation continuous renal replacement therapies in post-cardiac surgery patients with liver dysfunction

Abstract

The study's aim was to examine safety and efficiency of citrate anticoagulated continuous renal replacement therapies (CRRT) in cardiac surgery patients with acute kidney injury and associated liver dysfunction. The study was conducted on critical ICU patients, hospitalized after cardiac surgery, who developed renal and liver acute failures due to low-flow syndrome. CRRT in continuous veno-venous hemodiafiltration with regional citrate anticoagulation (RCA) was prescribed to address renal failure and avoid bleeding-risk. Patient Ca(++) was measured to monitor RCA safety, while thromboelastography (TEG) and circuit Ca(++) were used to verify efficacy. CRRT effectiveness was evaluated through creatinine and urea levels, while liver function was monitored through bilirubin, aspartate aminotransferase, glutamic oxaloacetic transaminase (AST GOT) and gamma glutamyl transferase (GT) levels. The study did not require ethical approval. Hepatic and renal failures were confirmed by baseline levels (total bilirubin=3.1 ± 3.37 mg/dL, AST GOT=153 ± 147 U/L and gamma GT=93.3 ± 86 IU/L, creatinine=1.97 ± 0.88 and blood urea nitrogen [BUN] 98.13 ± 71.34) assessed in 15 patients. During treatment, Ca(++) (patient and circuit) remained stable and within range for the whole therapy thanks to low citrate dose (2.8 ± 0.3 mmol/L of blood), while hepatic markers did not show any significant changes the therapy, although treatment with citrate is contraindicated in patients with hepatic failure. RCA quality was confirmed by TEG values, which showed an anticoagulated circuit with no effects on patients. These results involved a high filter lifespan (49.76 ± 22.10 h) and with an effective creatinine and BUN clearance. No episodes of citrate intoxication were reported (total/ionized calcium ratio remained stable and physiologic). RCA during CRRT with dilute solutions proved both effective and safe, even in patients with acute liver failure.

Keywords: Anticoagulation; Citrate; Continuous renal replacement; Liver dysfunction; Regional citrate anticoagulation; Thromboelastography.