Tandem Therapeutic Plasma Exchange and Continuous Kidney Replacement Therapy in a 3-kg Neonate: Technical Feasibility and Cicuit Considerations: An Abstract from Akron Children’s Hospital Resident and Fellow Academic Day

Therapeutic plasma exchange (PLEX) is rarely performed in newborn infants due to technical challenges, device size limitations, and the risk of hemodynamic instability associated with the large extracorporeal volume of the circuit. PLEX can be performed in tandem with continuous kidney replacement therapy (CKRT) (PLEX-CKRT), which increases the extracorporeal volume further. The extracorporeal volume of the PLEX-CKRT circuit exceeds the patient’s total blood volume (TBV), which necessitates a blood prime that is administered to the patient within minutes and effectively results in a rapid total body exchange transfusion. This places the child at risk for hemodynamic instability, hyperkalemia, hypocalcemia, acidosis, hypothermia, polycythemia, and potential clotting of the circuit. Neither PLEX nor CKRT is FDA-approved in infants, and protocols are lacking for how to perform this safely in infants. There are no specific reports describing how to perform PLEX-CKRT in infants. We describe the successful use of tandem PLEX-CKRT in a neonate and the measures taken to avoid the potential complications. We report a 10-day-old, 3-kg neonate who underwent tandem PLEX-CKRT. The patient presented with multiple organ dysfunction syndrome (MODS), profound metabolic acidosis, severely depressed biventricular function, and anuric acute kidney injury requiring CKRT. CKRT was initiated using the PrisMax system with HF20 membrane (circuit volume 58 mL), with a blood flow of 70 mL/min and a clearance of 1000 mL/min/m2. Heparin anticoagulation was used due to a citrate lock. Tandem PLEX with fresh frozen plasma (FFP) replacement was performed for thrombocytopenia-associated multi-organ failure (TAMOF) using the Spectra Optia apheresis system (235 mL). The combined circuit volume of the PLEX-CKRT circuit is 283 mL, which exceeds the patient’s approximate total blood volume of 250 mL. Special precautions were taken to account for the expected complications from the large amount of unphysiologic blood the patient would be receiving. 1) The system was primed with PRBCs reconstituted to a Hct of 40% to prevent polycythemia, 2) an additional heparin bolus was given to prevent clotting of the circuit, 3) the patient was warmed to prevent hypothermia, 4) epinephrine was started to maintain circulation, 5) a calcium bolus was given to prevent hypocalcemia, 6) sodium bicarbonate was given to correct acidosis, and 7) the CKRT circuit was run at a high clearance rate to prevent hyperkalemia from the large volume of blood. The patient tolerated three daily tandem PLEX-CKRT treatments without incident. Tandem PLEX-CKRT was successfully performed in a 3-kg neonate despite the large extracorporeal circuit volume that exceeded the patient’s total blood volume by anticipating the numerous potential complications associated with it and taking appropriate preventative measures. This demonstrates that PLEX-CKRT is technically feasible in infants.