Regional citrate anticoagulation in continuous hemodialysis--acid-base and electrolyte balance at an increased dose of dialysis.

Background: Citrate anticoagulation is an excellent alternative to heparin anticoagulation for patients at high risk of bleeding requiring continuous renal replacement therapy. However, citrate anticoagulation has some potential adverse effects such as metabolic alkalosis and acidosis, hypernatremia, hypo- and hypercalcemia. Thus, most citrate anticoagulation protocols use specially designed dialysis fluids to compensate for most of these disarrangements. This study aimed at establishing a citrate anticoagulation protocol designed for a dialysate flow rate of about 2 l/h.

Methods: Based on theoretical considerations we composed a dialysis fluid suitable for a 2 l/h dialysis flow rate. The dialysate contained 133 mmol/l sodium, 2 mmol/l potassium, 1.1 mmol/l magnesium, 25 mmol/l lactate, and 112.2 mmol/l chloride.

Results: Twenty-three patients were included in the study. During the treatments minor flow rate adaptations were needed and the treatments were well tolerated. Filter life was appropriate (51.3 +/- 24.6 h). Thirteen patients developed a mild metabolic alkalosis (pH > 7.45 plus BE > +3) which was easily counteracted by increasing the dialysis fluid flow (by increments of 500 ml). Acid-base values returned to normal within 24 h after increasing the dialysate flow. The maximum dialysate flow was 3,000 ml/h. Hypernatremia and hypocalcemia were not observed. The systemic ionized calcium concentration was successfully controlled by adjustments of a continuous calcium infusion made with respect to the results of 6-hourly measurements.

Conclusion: The analyzed citrate anticoagulation protocol was well tolerated and filter lifetime was appropriate. Regional anticoagulation with trisodium citrate in combination with a customized calcium-free dialysate is a safe and effective alternative to a heparin-based anticoagulation regimen.