Sensor-Based Physiologic Control Strategy for Biventricular Support with Rotary Blood Pumps
Rotary biventricular assist devices (BiVAD) are becoming a clinically accepted treatment option for end-stage biventricular failure. To improve BiVAD efficacy and safety, we propose a control algorithm to achieve the clinical objectives of maintaining left-right–sided balance, restoring physiologic flows, and preventing ventricular suction. The control algorithm consists of two proportional-integral (PI) controllers for left and right ventricular assist devices (LVAD and RVAD) to maintain differential pump pressure across LVAD (ΔPL) and RVAD (ΔPR) to provide left-right balance and physiologic flow. To prevent ventricular suction, LVAD and RVAD pump speed differentials (ΔRPML, ΔRPMR) were maintained above user-defined thresholds. Efficacy and robustness of the proposed algorithm were tested in silico for axial and centrifugal flow BiVAD using 1) normal and excessive ΔPL and/or ΔPR setpoints, 2) rapid threefold increase in pulmonary vascular or vena caval resistances, 3) transient responses from exercise to rest, and 4) ventricular fibrillation. The study successfully demonstrated that the proposed BiVAD algorithm achieved the clinical objectives but required pressure sensors to continuously measure ΔPL and ΔPR. The proposed control algorithm is device independent, should not require any modifications to the pump or inflow/outflow cannulae/grafts, and may be directly applied to current rotary blood pumps for biventricular support.