ESTIMATION OF SYSTEMIC VASCULAR BED PARAMETERS FOR ARTIFICIAL-HEART CONTROL

An extended Kalman filter (EKF) estimator for the identification of sy stemic circulation model parameters during cardiac ejection and cardia c filling is described. The estimator is being developed for use in th e control of a cardiac ventricular assist device. A lumped element cir cuit with a time-varying capacitor was used to represent the systemic circulation and the left ventricle. Since the hemodynamic variables th at are measurable in patients with impaired cardiac function vary dram atically as the patients move through different levels of care, the es timator was designed so that it can be used with different sets of blo od pressure and how measurements. Preliminary evaluation of the perfor mance of the estimator using data from a computer simulation and from a patient during open-heart surgery is presented. The robustness of th e estimator to variations in parameter initialization is also describe d.