New Findings on Pulsatile ECMO: Verification of the Potential to Improve Antithrombogenicity of a Membrane Oxygenator Using Pump-Generated Pulsatile Flow in an Innovative Animal Model.

Background: Extracorporeal membrane oxygenation (ECMO) provides mechanical circulatory and respiratory support. However, thrombus formation in the circuit can lead to hemorrhagic complications, requiring improvements in ECMO anti-thrombogenicity. Few studies have reported the effect of pulsatile flow on thrombus formation in ECMO circuits. This study evaluated how pulsatile flow affects thrombus formation inside the membrane oxygenator.

Methods: This study was conducted in pigs (n = 5) using an experimental model in which each pig was connected to two different ECMO circuits: one with steady flow (via the jugular vein and carotid artery) and the other with pulsatile flow (via the femoral vein and artery). The pulsatile waveform was generated as an upward sinusoidal waveform added to the baseline frequency. Both circuits were set to a mean flow rate of 2 L/min and operated for 4 h without anticoagulation. Thrombus formation in the membrane oxygenators was observed during and after circulation. The thrombus area was quantified using image analysis.

Results: All experiments were completed with stable hemodynamics. The pressure in the pulsatile circuit was confirmed to be a pulsatile waveform. The thrombus area in the steady flow circuits was 81.5%, 10.6%, 42.1%, 60.2%, and 96.7%, while those in the pulsatile flow circuits were 6.2%, 5.2%, 8.4%, 9.9%, and 65.8%, respectively. The thrombus area in the pulsatile flow circuit tended to be smaller than that in the steady flow circuit.

Conclusions: Pulsatile flow with a specific waveform may reduce thrombus formation in membrane oxygenators, potentially enhancing the anti-thrombogenicity of ECMO circuits.