The Use of a Circuit Simulation Program (SPICE 2) to Model the Microcirculation

Abstract

It has been possible to model and simulate a large variety of dynamic physiological systems using network thermodynamics (1) — (10). In this work, a model of the glomerular Filtration apparatus of the kidney (1) — (3) is adapted to capillaries in the microcirculation outside the kidney. For concreteness, the examples given will focus on studies by Gore and his coworkers (12) — (14) of single capillaries in the intestinal circulation of the rat. It should be emphasized that this system was chosen because it is well characterized and can serve as a benchmark for the network model. Since the network model is so easily modified, the study of this specific system can be readily extended to other aspects of the microvasculature. A number of similar studies on the entire cardiovascular system have been made by Rideout (4). Once a physiological system is translated into a network, it can easily be simulated on a circuit simulation program. We have found the program SPICE 2 (Simulation Package with Integrated Circuit Emphasis) to be very useful for this purpose (11). The program is easy to use, readily available for most computers at nominal cost, and versatile enough to simulate a wide variety of physiological processes.