Non-invasive method for estimating of the variation of the glucose level in the blood of a person and apparatus for carrying out the method

摘要

The estimation of the variation of the glucose level in the blood of a person by the variation of the volume of the interstitial fluid compartments in muscular tissue due to a shift of fluid between the extracellular and intracellular compartments caused by variations of the osmotic pressure of the extracellular fluids which is in turn correlated with the glucose level. The variation of the volume of the interstitial fluid compartments is detected by a non-invasive conductometry measurement using electrodes placed in contact with the skin of the person overlying a portion of soft tissue including muscular fibers. To eliminate the adverse effect of the conductivity of the capillary vessels, the conductivity of the tissue is measured independently in two directions, namely parallel and transverse to the muscular fibers.

主权项

1. A noninvasive method for estimating a variation of glucose level ΔG in the blood of a person within a time interval Δt, comprising the following steps:
placing a first tetrapolar electrode device in contact with skin of the person overlying a portion of soft tissue including muscular fibers oriented parallel to the direction of the muscular fibers; placing a second tetrapolar electrode device in contact with the skin of said person overlying said portion of soft tissue oriented transverse to the direction of the muscular fibers; measuring for a time interval Δt:
with the first tetrapolar electron device a relative variation ΔC∥,LF/C∥,LF of the conductivity value C∥,LF of said tissue parallel to the direction of the muscular fibers at a low frequency;with the second tetrapolar electron device a relative variation ΔC⊥,LF/C⊥,LF of a conductivity value C⊥,LF of said tissue transverse to the direction of the muscular fibers at said low frequency; estimating ΔG by a processing apparatus as:
0.0 if ΔC∥,LF/C∥,LF≈ΔC⊥,LF/C⊥,LF +a if ΔC∥,LF/C∥,LF>ΔC⊥,LF/C⊥,LF −a if ΔC∥,LF/C∥,LF<ΔC⊥,LF/C⊥,LF wherein: a is in the range of 0.15-1.0 μM/l sec; the low frequency is in the range of 1·×104 Hz-5·×104 Hz; and “≈” means “equal within a range of +/−2.5%-+/−7.5%”.