ID:177 FC-D07-6 In-Vitro Hemolysis Assessment of a Pneumatic Pulsatile ECMO Pump Using a Modified Mock Loop

Purpose: Pulsatile blood pumps aim to better replicate physiological cardiac output than continuous-flow systems. However, conventional hemolysis testing standards (ASTM F1841-97), developed for continuous-flow devices, may overestimate hemolysis in pulsatile pumps due to non-physiological single-reservoir circuits. This study evaluates the hemolytic performance of a newly developed pneumatically driven pulsatile ECMO pump and proposes a modified in-vitro circuit to reduce test-induced hemolysis. Methods: The pump employs parallel pneumatic chambers to generate synchronized pulsatile ejection. Two mock circulation loops were compared: (1) a conventional single-reservoir circuit and (2) a dual-reservoir circuit designed to split ejected flow and attenuate pressure fluctuations. Hemolysis testing followed ASTM F1831-19 and ASTM F1841-97. Heparinized porcine blood (prepared per ASTM F1830) was circulated for 6 hours at maximum flow rate with hourly sampling. Plasma-free hemoglobin (PfH) and normalized index of hemolysis (NIH) were measured. Results: The dual-reservoir configuration significantly reduced hemolysis. Maximum PfH decreased from 359 to 95 mg/dL, and average NIH decreased from 0.145 to 0.080 g/100L, indicating effective attenuation of pressure-induced shear stress. Conclusion: Conventional hemolysis protocols may overestimate hemolysis in pulsatile pumps. The proposed dual-reservoir circuit provides a more physiologically relevant platform for evaluating hemocompatibility in next-generation pulsatile ECMO systems.