In-vitro evaluation of multi-objective hemodynamic control of heart-assist pump

Ventricular assist devices (VADs) now clinically used for treatment of end-stage heart failure require responsive and reliable control to accommodate the continually changing demands of the body. This is an essential ingredient to maintaining a high quality of life. To satisfy this need, a control algorithm involving a tradeoff between optimal perfusion and avoidance of suction is developed. An optimal control strategy has been implemented in-vitro that combines two competing indices: representing venous return and prevalence of suction. The former is derived from the first derivative of diastolic flow with speed, and the latter derived from the harmonic spectra of the flow signal. The responsiveness of the controller to change in preload and afterload were evaluated in a mock circulatory simulator using a maglev centrifugal blood pump (CF4b, MedQuest Products). To avoid the need for flow sensors, an estimator is utilized, based on the back-EMF of the actuator. The multi-objective controller has demonstrated more robust performance as compared to controllers relying on individual indices.