Correcting hyponatremia by fluid sodium modulation in continuous renal replacement therapy with regional citrate anticoagulation.

A 40-year-old man presented with severe hyponatremia with a serum sodium of 102 mmol/L and concomitant acute kidney injury complicated by severe acidosis. He was started on continuous renal replacement therapy (CRRT) with regional citrate anticoagulation. We present the equations and strategy used to calculate and adjust the sodium concentration of the dialysate and replacement fluids to increase serum sodium levels by ≤8 mmol/L/day. The equations were based on fundamental chemistry principles and applicable to common CRRT solutions with 140 mmol/L of sodium. This simple strategy for CRRT fluid sodium titration required only one adjustment per day, and the serum sodium levels increased safely within the daily targets set. Although the citrated-replacement fluid was diluted for sodium adjustment, the citrate anticoagulation protocol was still able to achieve the targeted circuit ionized-calcium levels and provided adequate anticoagulation without issues related to frequent clotting and other electrolyte abnormalities.