Interaction between the Circulatory Effects and the Uptake and Distribution of Halothane: Use of a Multiple

A 12-compartment analog computer multiple model of the uptake and distribution of halothane in man is described. In this model an uptake and distribution model is combined with a circulatory model so that the two continuously influence each other. Cardiac output and its regional distribution were each controlled by the halothane concentration in any one of three compartments: arterial blood, brain (gray matter), and myocardium. Curves generated by this model differ significantly from those generated by a standard (linear) model. The magnitude of inspired concentration, but not the type of compartmental control, influences the rise time of alveolar concentration significantly. The circulation is influenced by both factors, particularly compartmental controls. The model is useful not only for predicting halothane concentrations, but also for gaining new insight into halothane-induced changes in the circulation: mean arterial pressure, cardiac output, and regional blood flows.