Simplified citrate anticoagulation for CRRT without calcium replacement.

Since 2012 citrate anticoagulation is the recommended anticoagulation strategy for CRRT. The main drawback using citrate compared with heparin as anticoagulant is the need for calcium replacement and the rigorous control of calcium levels. This study investigated the possibility to achieve anticoagulation while eliminating the need for calcium replacement. This was successfully achieved by including citrate and calcium in all CRRT solutions. Thereby the total calcium concentration was kept constant throughout the extracorporeal circuit while the ionized calcium was kept at levels low enough to avoid clotting. Being a completely new concept, only five patients with acute renal failure were included in a short, prospective, intensely supervised non-randomized pilot study.Systemic electrolyte levels and acid-base parameters were stable and remained within physiological levels. Ionized calcium levels declined slightly initially, but stabilized at 1.1 mmol/l. Plasma citrate concentrations stabilized at around 0.6 mmol/l. All post-filter ionized calcium levels were <0.5 mmol/l, i.e. an anticoagulation effect was reached. All filter pressures were normal indicating no clotting problems, and no visible clotting was observed. No calcium replacement was needed.This pilot study suggests that it is possible to perform regional citrate anticoagulation without the need for separate calcium infusion during CRRT.