Hypoglycaemia Detection by Ulm Sugar Watch System Indicating On-Line s.c. Glucose in Type-1 Diabetic Patients under Intensive Insulin Therapy

This chapter discusses a study focusing on hypoglycaemia detection by Ulm Sugar watch system indicating on-line s.c. glucose in type-1 diabetic patients under intensive insulin therapy. The Ulm Sugar Watch System consists of: (1) microdialysis probe inserted in the s.c. tissue, (2) Glucosensor Unitec Ulm, (3) sensor signal telemetrically transmitted to a wrist watch, (4) optic and acoustic alarm indicating provoked or spontaneous hypoglycaemia, and (5) minutely storage of s.c. glucose concentration for later evaluation before PC. The tissue glucose (T.G.) of patients under intensive-insulin treatment was on-line continuously monitored with glucosensor during hypoglycaemic clamps and under daily therapy. The blood glucose was clamped at 52 ± 4 mg/dl by means of the Bilostator. After clamping, blood glucose was conventionally assessed every 60 or 120 min. Calibration of the glucosensor was achieved by applying a one-point in-vitro , one-point in-vivo method. A further two-point in-vivo calibration and a simple mathematical algorithm a posteriori , yield the smoothing of the sensor's signal. The results showed that the blood glucose levels fluctuated between 40 and 400 mg/dl. The sensor signal correlated significantly with the correspondent blood glucose profiles. A delay of 5 to 10 min was determined.