A semi-closed loop computer-assisted insulin infusion system. Hospital use for control of diabetes in patients

Closed loop insulin delivery systems are impractical for widespread hospital use. Thus, a semi-closed loop computer-assisted insulin infusion system (CAIIS) was developed for the intravenous delivery of insulin. In its basal program, insulin delivery is determined by blood glucose measurements at intervals of three hours, while the open-loop meal program delivers 7.5 units over three hours. Control of meal-induced hyperglycaemia was satisfactory in six subjects with diabetes tested over two to four days, as was mean glycaemic control in the four non-obese subjects (7.1 +/- 0.8 mmol/L). To allow for variations in insulin sensitivity, an adjustment incrementing or decrementing the basal insulin delivery rate was applied according to the progressive blood glucose response. Empirical use of this adjustment resulted in good control (mean blood glucose level, 4.1-7.5 mmol/L) in 10 additional subjects with diabetes. This study demonstrates the potential usefulness of a semi-closed loop insulin infusion system.