A variable gain physiological controller for rotary ventricular assistent devices.

Abstract

This work involves designing a physiological adaptive control law for a turbodynamic ventricular assist device (TVAD) using a lumped parameter time-varying model that describes the cardiovascular system. The TVAD is a rotary blood pump driven by an electrical motor. The system simulation also includes the adaptive feedback controller, which provides a physiologically correct cardiac output under different preload and afterload conditions. The cardiac output is estimated at each heartbeat, and the control objective is achieved by dynamically changing the motor speed controller’s reference based on the systolic pressure error. TVADs provide support for blood circulation in patients with heart failure. Several control strategies have been developed over the years, emphasizing the physiological ones, which adapt their parameters to improve the patient’s condition. In this work, a new strategy is proposed using a variable gain physiological controller to keep the cardiac output in a reference value under changes in both preload and afterload. Computational models are used to evaluate the performance of this control technique, which has shown better adaptability results than constant speed controllers and constant gain controllers.