Citrate anticoagulation realized as CVVHD using a newly designed dialysate solution

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, hypocalcemia and hypercalcemia. Thus, most citrate anticoagulation protocols use specially designed dialysis fluids to compensate for most of these disarrangements. We present a newly designed dialysate for citrate anticoagulation and looked at the filter life time, acid-base and electrolyte disarrangements.

Methods

Based on theoretical considerations we composed a dialysis fluid suitable for a 2 l/hour dialysis flow rate. The dialysate contained 133 mmol/l sodium, 2 mmol/l potassium, 1.1 mmol/l magnesium, 20 mmol/l bicarbonate and 112.2 mmol/l chloride. All treatments were performed as CVVHD. Routine filter changes were performed after 72 hours of treatment.

Results

Forty-five patients were included in the study. Treatments were well tolerated. The filter life was appropriate (57.4 ± 17 hours). In a few patients mild metabolic alkalosis (pH > 7.45 plus BE > +3) was easily counteracted by increasing the dialysis fluid flow. Acid-base values returned to normal within 24 hours after increasing the dialysate flow. The maximum dialysate flow was 3000 ml/hour. 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 the filter life time 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.