Abstract
To make a therapeutical assessment of subcutaneous insulin infusion with an open-loop system, a comparative evaluation of the following 5 different insulin treatments was performed in diabetics: treatment with an artificial beta cell system (Closed-Sysiem), intravenous infusion with an open-loop system (IV Open-System), subcutaneous infusion with an open-loop system (SC Open-System), multiple short-acting insulin injections (S-A Injections), and intermediate-acting insulin iniection (I-A Iniection).
A 24-hour glycemic control was attempted in 6 newly insulin-requiring diabetics for 5 consecutive days by the aforementioned insulin regimens.
Similar insulin infusion to the Closed-System was repeated in the 1 V Upen-6ystem with a Preprogrammable Insulin Infusion Pump. In the SC Open-System, 1.3 to 1.5 times as much insulin as in the IV Open-System was commenced 30 mill prior to each meal. The amount of insulin required in the SC Open-System was given in the S-A and I-A Injections.
1) Perfect normalization with a physiological plasma insulin profile could be achieved with the Closed-System. The IV Open-Systm was capable of maintaining glycemia within the normal range. Plasa insulin and glucagon were almost normalized.
2) Diabetic control, as assessed from the mean plasma glucose, M-value and mean amplitude of glycemic excursions, was in the favorable order of Closed-System, IV Open-System, S-A Injections, SC Open-System and I-A Injection, respectively.
3) With the insulin infusion programme used in the present study, the SC Open-System could not simulate the physiological plasma insulin profile. In terms of diurnal glycemic regulation, the SC Open-System was shown to be superior to the I-A Injection, but was of no advantage over the S-A Injections, except in nocturnal glycemic control.
The above results indicate that the development of an original and suitable insulin infusion programme for the SC Open-System is urgently required.
