Pulsatile blood flow is considered more potential for delivering hemodynamic energy and enhancing microcirculatory perfusion in patients compared to non-pulsatile flow in ECMO. This study aims to systematically evaluate the effects of different blood flow modes on the hemodynamic environment, thrombosis risk, and oxygen transport within oxygenators.

QUADROX-i Adult Oxygenator was investigated using CFD to simulate its hemodynamic environment under different blood flow modes, comprising one non-pulsatile condition and nine pulsatile conditions with varying frequencies and amplitudes. The stasis (ART) and hypercoagulability (C[FXIa]) were used to assess the thrombosis risk and oxygen transport (PO₂) was also analyzed. The dynamic blood volume (DBV) were calculated to reflect the effective volume within the oxygenator.

Under all blood flow modes, the velocity distribution is more uneven in inlet-side and outlet-side transition regions, and the high value is near the inlet and outlet, and becomes lower away from the inlet and outlet. In gas exchange region, the velocity is low and evenly distributed. The region with the highest ART and C[FXIa] are located at the north corner region close to the outlet. The highest PO₂ evenly appears in the region near the outlet. Under pulsatile conditions, As the flow rate increases, the distribution of velocity, ART and C[FXIa] becomes more uneven, and vice verse. Compared to non-pulsatile condition, the period-averaged ART, C[FXIa] and PO₂ become higher, while the DBV decreases under pulsatile conditions. Amplitude has a more significant effect on all parameters than frequency. Higher amplitude results in the higher period-averaged ART, C[FXIa] and PO₂, alongside a lower DBV.

Uneven flow field mainly occurs in the inlet-side and outlet-side transition region, and the uneven degree increases with the higher flow rate, and vice verse. The highest thrombosis risk locates in the north corner region close to the outlet and the highest oxygen transport occurs in the region close to the outlet. Pulsatile flow can enhance oxygen transport but increase thrombosis risk than non-pulsatile flow. Higher amplitude can increase thrombosis risk but improve oxygen transport in the oxygenator. The frequency variation exhibits minimal influence.