A hybrid systems approach to integration of medical models

The authors discuss a fundamental problem in the provision of quality care at acceptable, society-wide costs: The integration of what is now a dichotomy in medical models. The dichotomy is one between phenomenological models of high-level decisions and evolution models of low-level dynamics. The dominant modeling concepts are based traditionally on (a) "homeostasis" and, (b) "physical dynamics"-such as those encountered in pharmacology, quantitative pathophysiology, and immunology. The authors introduce a novel idea of the hybrid system state which is used to provide a basis for integration of medical models.<>