Computer Simulation of Optimal Insulin Profiles in Diabetic Patients

Abstract

Various types of the insulin delivery systems have been used for the treatment of diabetic patients to maintain the blood glucose level within normal range (Slama et aL, 1974; Deckert et aL, 1977; Genuth et aL, 1977; Bojsen et aL, 1978; Tambolane et aL, 1979). In utilizing these systems, an optimal insulin infusion rates and its patterns after meals are determined by trial and error methods, as the required insulin patterns are different from one patient to anothe r. In these empirical methods,the endogenous insulin delivery patterns of non-diabetic subjects have been used as an initial reference information , Then, by adjusting the insulin infusion rates every day and evaluating the blood glucose level , the final optimal insulin pattern is determined when the glucose level remains within normal range, This adjusting procedure usually takes about one week in our clinical experience, and other reported results(Genuth et aL,1977) , These results suggest that normal subjects insulin delivery pattern may not provide a satisfying reference information in determining the optimal insulin infusion pattern for diabetic patients, For example, the same amount of insulin has different effects on glucose control in normal and diabetic groups, since each group has significantly different hepatic glucose balance function and insulin resistivity at tissue sites(Bergman et aL, 1974; Kimmerling et aL, 1976; Youn et aL, 1981) Therefore, it is desirable to develop a quantitative method of estimating the optimal insulin infusion pattern rcquired to maintain glucose level within nonnal range for a specific subject. As a preliminary study of a ne찌 approach, we will present a computer simulation method in which the optimal plasma insulin concentration profile after intravenous glucose loading is computed from an analysis of the intravenous glucose tolerance test (IVGTT) based on the equivalent circuit model of the glucose kinetics (Youn et aL, 1981) .