Adaptive control of left ventricular assist devices

This paper presents a computer based adaptive control system for left ventricular assist devices consisting of air driven diaphragm pumps. The system will maintain both the aortic and left atrial pressures of the recipient precisely at desired levels. The system design includes a two-input-two-output adaptive control algorithm which determines the values of the control variables which become inputs to a servo-loop controlled pneumatic pressure source. The performance of the system has been demonstrated by in vitro experiments on a mock circulatory system. The results demonstrate that the assist system will maintain the essential blood pressures precisely at desired levels. Furthermore, when major changes in the output of the mock loop left ventricle occur, the algorithms retunes itself and restores the pressures to desired levels within 10 beats. Hence, we conclude that the system has performance characteristics which are highly desirable for clinical applications.