Online parameter identification of systemic circulation model using delta-operator in animal experiment

To develop an effective medical care with the internal medical robot, artificial heart, we proposed an online parameter identification of systemic circulation model using delta-operator, which can calculate the time varying and unmeasured hemodynamics of the internal human body from some measured physiological data: Aop (aortic pressure), AoFlow (aortic flow) and Pflow (pump flow). This method consists of: (1) the systemic circulation model, which was configured with Ca (aortic compliance), Ra (aortic resistance), L (aortic inertia) and Rp (total peripheral resistance); and (2) system identification using delta operator. In the computer simulation, we confirm the effectiveness of the proposed method. In animal experiment with the left ventricular assist system, the physiological parameters were identified as: Ra=0.04 mmHg sec/ml, Ca=0.7 mmHg/ml, L=0.02 mmHg sec sec/ml, Rp=0.3 mmHg sec/ml. By the identified parameters, we estimate the physiological behaviors. This method will bring the new stage of development of the artificial heart.