Ability of a novel system for neonatal extracorporeal renal replacement therapy with an ultra-small volume circuit to remove solutes in vitro.

BACKGROUND: We automated our manual, syringe-driven extracorporeal renal replacement therapy (eRRT) system with an ultra-small volume circuit (3.2 ml) that is suitable for neonates without blood priming. Our objective was to determine the solute clearance and water balance of the automated and manual systems in vitro.

METHODS: Stored whole blood samples containing exogenous urea, creatinine (Cr), potassium (K), and ammonia (NH3) to imitate acute kidney injury (AKI) and hyperammonemia were dialyzed for 3 h (blood flow, 4.0 ml/min; dialysate flow, 600 ml/h) with a continuous infusion of heparin. Solute clearance and sample weight were then compared with values before dialysis.

RESULTS: The median clearance of blood urea nitrogen, Cr, K, and NH3 ranged from 1.7 to 2.3 and from 2.4 to 2.6 ml/min, and the median weight of the samples was decreased by 3.8 g and increased by 8.3 g after 3 h of dialysis using the manual and automated systems, respectively.

CONCLUSIONS: The automated system effectively cleared solutes, but safety concerns were associated with platelet consumption and fluid balance. Additional studies are needed to establish the safety and accuracy of this novel system for clinical use in neonates and preterm infants.