Citrate kinetics in patients receiving long-term hemodialysis therapy

Background: Regional anticoagulation using sodium citrate is used increasingly in hemodialysis patients at high risk for bleeding. However, citrate metabolism has never been evaluated systematically in hemodialysis patients, and it remains to be shown that citrate is cleared adequately in the presence of renal dysfunction. This study compares the pharmacokinetics of citrate in hemodialysis patients with minimal residual function with that in patients with normal renal function. Methods: Long-term hemodialysis patients (n = 7) and patients without renal failure (n = 11) were investigated during routine immunoadsorption treatment by using a standardized citrate infusion protocol. Serial analysis of blood samples was performed before, during, and up to 120 minutes after citrate infusion (0.33 mmol/kg/h). Citrate plasma concentrations were measured colorimetrically. In addition, ionized calcium, pH, and bicarbonate were measured by using a blood gas analyzer. Results: Basal (0.09 ± 0.03 versus 0.12 ± 0.03 mmol/L; P = not significant) and peak citrate concentrations were similar in both groups (1.24 ± 0.42 versus 1.19 ± 0.33 mmol/L; P = not significant). Citrate clearance was similar in patients with renal failure (0.31 ± 0.06 L/min) and controls (0.35 ± 0.11 L/min; P = 0.47). Effects on pH were minimal and did not differ between groups. No patient developed complications from citrate infusion. Conclusion: Compared with controls, citrate clearance and metabolism in long-term hemodialysis patients is not impaired, and no significant acid-base disorder occurred during citrate anticoagulation. From these data, it is tempting to conclude that citrate anticoagulation can be used safely in patients with chronic renal failure on regular hemodialysis therapy.