A Retrospective Review of the Use of Regional Citrate Anticoagulation in Continuous Venovenous Hemofiltration for Critically Ill Patients

Background. The emergence of a commercially prepared citrate solution has revolutionized the use of RCA in the intensive care unit (ICU). The aim of this study was to evaluate the safety profile of a commercially prepared citrate solution. Method. Predilution continuous venovenous hemofiltration (CVVH) was performed using Prismocitrate 10/2 at 2500？mL/h and a blood flow rate of 150？mL/min. Calcium chloride solution was infused to maintain ionized calcium within 1.0–1.2？mmol/L. An 8.4% sodium bicarbonate solution was infused separately. Treatment was stopped when the predefined clinical target was reached or the filter clotted. Result. 58 sessions of citrate RCA were analyzed. The median circuit lifetime was 26.0？h (interquartile range IQR 21.2–44.3). The percentage of circuits lasting more than 12？h, 24？h, and 48？h was 94.6%, 58.9%, and 16.1%, respectively. There was no incidence of hypernatremia and median pH was <7.5. Hypomagnesemia and hypophosphatemia were detected in 41.6% and 17.6% of blood samples taken, respectively. Although 16 episodes had a total calcium/ionized calcium (total Ca/iCa) >2.5, only four patients had evidence of citrate accumulation. Conclusion. The commercially prepared citrate solution could be used safely in critically ill patients who required CVVH with no major adverse events. 1. Introduction Regional citrate anticoagulant (RCA) has been widely used in continuous renal replacement therapy (CRRT) [1–16]. Its use has been greatly simplified by the development of a commercially prepared citrate solution [11–16]. Shum et al. [14] reported a simple citrate regime in 10 critically ill patients using the commercial citrate solution. We would like to expand the use of this regime to a larger group of patients and in an intensive care unit (ICU) with limited prior experience in the use of RCA. We chose this regime because it is simple to set up. First of all, the blood flow and the substitution fluid rate were fixed to give a constant blood citrate concentration and to eliminate regular measurement of prefilter ionized calcium (iCa). The procedure involved only one replacement solution, Prismocitrate 10/2 (Gambro-Hospal, Stockholm, Sweden). As the amount of base produced was only 30？mmol/L bicarbonate, an external pump was used to infuse the sodium bicarbonate via the heparin port of the circuit to supplement the base required (Figure 1). Figure 1: Diagram of predilutional continuous venovenous hemofiltration using Prismocitrate 10/2 solution and Prismaflex machine. Following 3 months of staff training, citrate CRRT was first