A model of overall regulation of body fluids

A large-scale model of body fluid regulation was presented for the purpose of studying problems concerning body fluid disturbances and fluid therapy. This model, containing subsystems o f circulation, respiration, renal function, and intra and extracellular fluid spaces, was described mathematically as a set of non-linear differential and algebraic equations of more than 200 variables. A special feature is that the respiratory and renal subsystems are combined into one system, so that acid-base disturbances of body fluid can be simulated over a wide range of time scales. Behavior of the model for various kinds of inputs simulated with a digital computer was in good agreement with a number of experimental results pertaining to body fluid and acid-base disorders. The model presented in this paper is considered to have good applicability to some clinical problems and to be a useful framework for physiological experimental research