Experimental Assessment of Flow Within a Pediatric Ventricular Assist Device

Particle-image velocimetry is used to study the flow within a pediatric ventricular assist device (PVAD) operating in the range of 60--100~beats per minute, with particular interest in identifying flow patterns that may promote detrimental processes like hemolysis and/or thrombosis. To this end, phase-locked PIV measurements are made in planes parallel to a pneumatically-driven membrane that controls the flow into and out of the PVAD's blood chamber. Preliminary results show that velocities exceeding 1~m/s can exist in these relatively small devices and that the instantaneous flow patterns can be quite vigorous. In particular, while phase-averaged fields appear to represent the bulk, large-scale features of the flow within the blood chamber of the PVAD, small-scale cycle-to-cycle variability is also quite apparent, most notably during the diastole phase when the membrane is retracting from the blood chamber. This cycle-to-cycle variability is found to increase with beating frequency.