Changes in Serum Electrolytes at Different Glucose Concentrations + Impact on a Non-invasive Glucose Monitoring Method

• plasma ion concentrations (sodium, potassium, chloride, calcium, magnesium) and osmolarity [ Time Frame: blood samples every 10 min during baseline, plateau hyperglycemic and final euglycemic phase, every 5 min during increase and decrease of blood glucose ] [ Designated as safety issue: No ]
  

• blood glucose concentration [ Time Frame: continuously during glucose clamp ] [ Designated as safety issue: Yes ]
  

Device: Non-invasive CGMS
A non-invasive continuous glucose monitoring device measured was applied at the wrist and measured skin glucose as an indirect measure of blood glucose every 10 min.
Other Name: PendraWatch
Procedure: Hyperglycemic glucose clamp
The automated glucose clamp technique was used to control glucose levels at baseline glycemia for 1h, hyperglycemia (16.7 mmol/L) for at least 2.5h and euglycemia (5 mmol/L) for another 2.5h. A continuous somatostatin infusion was initiated after 1h to suppress endogenous insulin secretion. A glucose solution was infused to increase the blood glucose towards the hyperglycemic target level. At approximately t=3.5h the somatostatin infusion was stopped and blood glucose was controlled at the euglycemic target level.
Other Names:
• Biostator
• Somatostatin

Non-invasive continuous glucose monitoring is a promising approach in diabetes therapy. It is known that changes in glucose concentration in the skin can be registered by means of optical, spectroscopic measures in subjects with diabetes. The precision of such measures, however, so far has been unsatisfactory.

This study evaluates the changes in skin glucose concentration by means of a non-invasive glucose sensor and compares these to blood glucose concentrations during a glucose clamp. It is also known that with hyperglycemic blood glucose concentrations there is a consecutive hyponatraemia. This study shall evaluate to which extent and how fast serum electrolyte parameters change when establishing a hyperglycaemic blood glucose level. This shall help estimate which impact these changes in electrolytes have on the non-invasive glucose sensor.