An automatic control algorithm for the optimal driving of the ventricular-assist device.

This paper presents a new method of keeping one of the most suitable driving conditions for regulating the outflow volume from the ventricular-assist device (VAD). The experimental results from a mock circulatory system have shown that the relationship between the stroke volume and the systolic duration of the VAD can be specified by the combination of characteristic curves of the positive and negative drive pressures. The optimal operating point on the characteristic curve have been defined as the point at which thrombosis on the blood-contacting surface and hemolysis due to mechanical damage can be avoided and at which the driving energy can be minimized. The present analysis has been revealed that the optimal operating point is the vertex of the triangular figure obtained from the characteristic curve. The algorithms for keeping the optimal operating point and for regulating the stroke volume have been also proposed.