A Sensorless non-linear Control algorithm for Continuous Flow Right Ventricular Assist Devices

Continuous flow right ventricular assist devices are mechanical circulatory support devices that are implanted in patients with end-stage heart failure. Right-sided heart failure often occurs in conjunction with the left-sided heart failure or can occur on its own as a result of heart attacks, dilated and hypertrophic cardiomyopathy or valvular diseases. Here, we propose a control algorithm for a continuous flow assist right ventricular assist devices that can maintain physiologic perfusion and avoid ventricular suction under various physical conditions using only the intrinsic pump speed. The algorithm maintains a differential pump speed setpoint using a proportional-integral controller. To test the robustness of the proposed algorithm, we used a previously validated mathematical model of the circulatory system coupled with a model of a continuous flow ventricular assist device to test the control algorithm in-silico. The robustness and efficacy were evaluated by comparing the control algorithm to constant speed control during (1) rest condition, (2) exercise conditions, and (3) a rapid 30% increase in vena caval resistance during rest. The proposed algorithm performance was compared to the clinical constant speed control under these condtions. The proposed differential speed algorithm provided adequate perfusion by varying pump speed and flow while preventing ventricular suction for all test conditions. This algorithm does not require unreliable sensors, complicated parameter estimations, or any modifications to the pump and can readily be applied to current devices.