Development of a Plasma Free Hemoglobin-Adsorbing Device for Extracorporeal Therapies

In extracorporeal therapies such as cardiopulmonary bypass (CPB) or extracorporeal membrane oxygenation (ECMO), the transport of blood through artificial circulation frequently results in the rupture of erythrocytes, releasing hemoglobin (Hb) into the plasma (fHb), and exhausting the body's supply of the natural fHb scavenger-haptoglobin (Hp). This complication, known as mechanical hemolysis, results in the release of fHb and its downstream heme-containing degradation products and is associated with multi-organ dysfunction and adverse outcomes. Current strategies for mitigating hemolysis in extracorporeal circuits are either resource-intensive or nonspecific. Here, we describe the fabrication and benchtop evaluation of an fHb-adsorbing device intended as an adjunctive, intermittent, time-limited approach to reduce fHb. Human Hp was immobilized onto a cross-linked agarose resin and loaded into a packed-bed device compatible with whole-blood perfusion. Under controlled recirculation conditions, the device demonstrated the ability to capture fHb and attenuate its accumulation relative to control. A regenerative protocol was developed to disrupt the Hp-Hb complexes and restore a substantial fraction of Hp binding activity. These findings support both the feasibility of immobilized Hp for selective fHb capture under benchtop conditions as well as the need for further device optimization and evaluation in more physiologically representative extracorporeal models. https://links.lww.com/ASAIO/B922.