A continuous veno-venous hemofiltration protocol with anticoagulant citrate dextrose formula A and a calcium-containing replacement fluid.

ABSTRACT

INTRODUCTION: Regional citrate anticoagulation (RCA) is used as an anticoagulant for continuous renal replacement therapy (CRRT). A systemic calcium (Ca2+) infusion is required to replace Ca2+ lost in the effluent. The shortage of intravenous Ca2+ in the United States has limited RCA use. We describe a continuous veno-venous hemofiltration (CVVH) protocol with RCA using 2.2% anticoagulant citrate dextrose formula-A (ACD-A) and a commercial dialysate containing Ca2+ 1.5 mmol/l (N × Stage) as post-filter replacement fluid (RF), without need for Ca2+ infusion. METHODS: We prospectively evaluated five patients on CRRT who had at least three episodes of filter clotting within 24 h. Patients were switched to CVVH using ACD-A infused pre-blood pump and titrated to achieve a post-filter ionized calcium (iCa2+) level <0.5 mmol/l. The Ca2+ -containing dialysate was delivered post-filter as RF. RESULTS: Steady state mean serum chemistries were Na+ 140.8 ± 2.3 meq/l, K+ 4.2 ± 0.4 meq/l, HCO3- 30.9 ± 3.7 meq/l, pH 7.42 ± 0.07, CO2 47.9 ± 8.3 mmHg, total Ca2+ 8.08 ± 1.09 mg/dL. Post-filter iCa2+ ranged 0.27-0.36 mmol/l, and patient iCa2+ ranged 0.81-1.24 mmol/l. Mean post-filter RF rate 3086 ± 164 ml/h, mean ACD-A rate 298 ± 21 ml/h. Mean blood flow rate 200 ± 17 ml/min, mean filtration fraction 39.6 ± 7.2%. Mean effluent flow rate 38.6 ± 6.7 ml/kg/h (range 28.7-55.8). Mean filter survival was 7 h without anticoagulation, compared to 42.6 h in the ACD-A group (p<0.0001). CONCLUSIONS: In this pilot study, CVVH using ACD-A for RCA and a Ca2+ -containing RF was safely and effectively used without a continuous Ca2+ infusion. This protocol is a promising solution for maintaining effective CRRT when intravenous calcium is in short supply.