MIXED QUANTITATIVE QUALITATIVE MODELING AND SIMULATION OF THE CARDIOVASCULAR-SYSTEM/

The cardiovascular system is composed of the hemodynamical system and the central nervous system (CNS) control. Whereas the structure and fu nctioning of the hemodynamical system are well,known and a number of q uantitative models have already been developed that capture the behavi or of the hemodynamical system fairly accurately, the CNS control is, at present, still not completely understood and no good deductive mode ls exist that are able to describe the CNS control from physical and p hysiological principles. The use of qualitative methodologies may offe r an interesting alternative to quantitative modeling approaches for i nductively capturing the behavior of the CNS control. In this paper, a qualitative model of the CNS control of the cardiovascular system is developed by means of the fuzzy inductive reasoning (FIR) methodology. FIR is a fairly new modeling technique that is based on the general s ystem problem solving (GSPS) methodology developed by G.J. Klir (Archi tecture of Systems Problem Solving, Plenum Press, New York, 1985). Pre vious investigations have demonstrated the applicability of this appro ach to modeling and simulating systems, the structure of which is part ially or totally unknown. In this paper, five separate controller mode ls for different control actuations are described that have been ident ified independently using the FIR methodology. Then the loop between t he hemodynamical system, modeled by means of differential equations, a nd the CNS control, modeled in terms of five FIR models, is closed, in order to study the behavior of the cardiovascular system as a whole. The model described in this paper has been validated for a single pati ent only. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.