Diabetes closed-loop control

Figure 1. Artificial pancreas block diagram. Closed-loop control (—) uses the sensor ana programmers to direct flow controller. In open-loop control (—), augmentation is initiated by the diabetic, without the sensor. Typical design criteria are indicated on the right-hand side of the drawing.

Kovatchev, B. R, Breton, M., Man, C. D. and CobeUi, C. 2009. In sUico preclinical trials A proof of concept in closed-loop control of type 1 diabetes. / Diab Sci Technol, 3,44-55. 

The closed-loop type artificial pancreas (specifically 8-cell), which consists of an automatic continuous monitor of blood glucose level (BGL) and an automatic injector of insulin which are coupled with feed-back system, has great potential for prevention of diabetic complication such as micro-angiopathies(l). A large-scale closed-loop type artificial pancreas for bedside use has already been developed and is clinically used at some laboratories and hospitals (2-4). However, this device is limited to only bedside use. On the other hand, the open-loop type artificial pancreas which consists of only a insulin injecting pump without an automatic continuous monitor of BGL, has been developed and is going to be clinically used(5-7). This system, however, can not completely control BGL as well as the bare pancreas in a normal body and often causes lower BGL(8-9). 

The application of an artificial endocrine pancreas (AEP=Biostator) with feedback control could be useful in the clinical management of unstable diabetics (Ohno et al., 1983). Former early closed-loop devices were large bedside machines (Pfeiffer et al., 1974) with only limited application for long-term use. More recent research has developed small glucose sensors which, however, have had only preliminarily testing for clinical application. External insulin pumps must be further miniaturized and technical failure... 

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