Super High‐Flux Continuous Venovenous Hemodialysis Using Regional Citrate Anticoagulation: Long‐Term Stability of Middle Molecule Clearance

Continuous renal replacement therapy is a standard treatment in critically ill patients with acute kidney injury. All CRRT techniques provide a high low‐molecular weight clearance but even with hemofiltration, clearance of middle molecules is low. We investigated whether a new super high‐flux hemofilter provides effective and sustained middle molecule clearance during citrate‐anticoagulated continuous venovenous hemodialysis for up to 72 h. We included 14 critically ill patients with AKI‐KDIGO‐III in a prospective observational trial. We measured/calculated blood and urine concentrations, clearances and sieving coefficients of eight molecules with molecular weights from 60 to 66 kDa, hemodynamic parameters and SAPS‐II scores. All filters were patent at 72 h. Clearance and sieving coefficients of small solutes were high and sustained over time, those for larger solutes decreased over 72 h but remained high enough to decrease blood concentrations of solutes up to 25 kDa. Albumin serum levels remained unaffected. Catecholamine doses and SAPS‐II scores decreased significantly. This new hemofilter may improve blood purification in critically ill patients with AKI.