Implementation of the Natural Heartbeat Synchronize Control for the Undulation Pump Ventricular Assist Device Using the Inflow Pressure

Abstract

The undulation pump ventricular assist device (UPVAD) is a small implantable ventricular assist device using an undulation pump. The UPVAD can produce not only continuous flow but also pulsatile flow by changing the motor rotational speed of the UPVAD. Because the undulation pump is a volume displacement type pump in which the inflow action and outflow action both start at the same phase, the inflow sucking occurs easily. The purpose of this study is to develop a suitable control method for the UPVAD. The UPVAD inflow cannula equipped with an implantable blood pressure sensor is inserted into the ventricular. Therefore, pressure fluctuation that synchronizes with the natural heartbeat is observed in the inflow cannula. By changing the motor rotational speed that responds to the inflow pressure, the UPVAD can synchronize with the natural heartbeat and the UPVAD can generate either aco-pulse assist flow or a counter pulse assist flow. The newly developed control method exhibited superior characteristics than existing ones due to high immunity against pressure sensor drift. The improved control method is implemented into the microcontroller. The UPVAD generated 5.3 l/min co-pulse assist flow without inflow cannula sucking using this control method. The assist flow can be increased more than 15% with this control method. This control was implemented one-chip microcontroller without extra peripheral device. It can reduce the UPVAD controller size. The UPVAD can generate the suitable assist flow with the developed control method.