Supplementary Material for: A Comparison between Two Dilute Citrate Solutions (15 vs. 18 mmol/l) in Continuous Renal Replacement Therapy: The Base Excess and Renal Substitution Solution Study

Background/Aims: The study aimed to compare the changes in biochemistry occurring in patients undergoing continuous renal replacement therapy (CRRT) using 2 trisodium citrate solutions, Baxter hemofiltration fluid containing 18 mmol/l (C18) and Baxter NamSol, a custom manufactured solution containing 15 mmol/l (C15), both delivered as regional citrate anticoagulation (RCA) predilution fluids for hemofiltration. Methods: This is a prospective randomized control trial conducted in a major regional adult intensive care unit. Patients were randomized to 1 of 2 RCA fluids. Progress was monitored using a standard daily panel of acid-base and biochemical tests. Results: Forty-eight patients, 23 C18 and 25 C15, were recruited. In both groups, acidosis resolved within 36 h of institution of CRRT. By day 3, there were significant differences in serum [Na⁺], standard base excess and serum bicarbonate concentration, all being higher in the C18 group (p < 0.01). By day 5, the PaCO₂ had also risen in the C18 group (p = 0.03). Conclusions: The C15 solution provided equivalent filter life to the C18 solution but without significant hypernatremia and metabolic alkalosis.