Non-invasive continuous blood glucose monitoring

• US 5,823,966 A
• Filed: 05/20/1997
• Issued: 10/20/1998
• Est. Priority Date: 05/20/1997
• Status: Expired due to Fees

• Current Assignee: Infratec Incorporated
• Original Assignee: Janusz Michal Buchert
• Inventors: Buchert, Janusz Michal
• Primary Examiner(s): Bahr, Jennifer
• Assistant Examiner(s): YARNELL, BRYAN KEITH
• Application Number:
  US08/859,579
• Time in Patent Office: 518 Days
• Field of Search: 600/310, 600/314-316, 600/322-328, 600/339-342, 600/473, 600/475, 356/39-41
• US Class Current: 600/473
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/6817 Ear canal
• CPC Class Codes: G01J 5/0802 Optical filters
• CPC Class Codes: G01J 5/14 Electrical features thereof

Abstract

A method and an instrument for a continuous non-invasive detection of an analyte (e.g. glucose) concentration in a human body tissue such as blood is discussed herein. The instrument remote sensor assembly mounted in subject'"'"'s ear canal continuously measures analyte concentration by detecting the infrared radiation naturally emitted by a human body. It uses an infrared detector with a combination of adequate filters such as, for example, a negative correlation filter or narrow band filters or other detector-filter assemblies. The method and instrument is based on the discovery that natural infrared emission from the human body, especially from the tympanic membrane, is modulated by the state of the emitting tissue. Spectral emissivity of human infrared radiation from the tympanic membrane consists of spectral information of the tissue (e.g. blood) analyte (e.g. glucose). This can be directly correlated with the blood analyte concentration, for example, the blood glucose concentration.

Claims

1. A method of determining continuously a human body tissue analyte concentration by non-invasive measurement of emission spectral lines characteristic to a body tissue analyte in an infrared spectral region emitted naturally by a human body as heat, comprising:

a. measuring continuously a spectral intensity of said emission lines;

b. said emission spectral lines having a wavelength dependence of tissue constituents;

c. detecting continously the emission spectral lines at a predetermined emission wavelength;

d. analyzing the emission spectral lines in said infrared spectral region;

e. correlating said spectral intensity of emission spectral lines with body analyte concentration.

2. The method as in claim 1, for determining blood glucose concentration continuously by non-invasive measurements of emission spectral lines characteristic to a body tissue analyte in an infrared spectral region emitted naturally by a human body'"'"'s tympanic membrane in an infrared wavelength spectrum as heat.

7. The instrument of claim 2, where the correlating means is --an electronic device comprising--electronics and a microcomputer for correlating--a--state of--an--electronic output signal from the detecting means with the tissue analyte concentration.

3. An instrument for determining continuously a human body tissue analyte concentration by non-invasive measurement of emission spectral lines characteristic to a body tissue analyte in an infrared spectral region emitted naturally by a human body as heat, comprising:

a. a means for detecting continuously said emission spectral lines at a predetermined infrared wavelength;

b. a means for detecting continuously a spectral intensity of the emission spectral lines;

c. a means for correlating the intensity of emission spectral lines with the tissue analyte concentration.

4. The instrument of claim 3 wherein the detecting means comprises a detector means and an analyzing means for wavelength selecting means of the emission spectral lines;

detector means for detecting continuously the intensity of received emission spectral lines from said analyzing means producing an electrical output signal; and

wavelength selecting means for allowing only significant wavelengths of tissue analyte emission spectral lines in natural infrared radiation emitted by the human body to reach the detector means.

5. The instrument of claim 4, wherein the detector means is infrared energy sensors for continuous infrared energy measurements.

6. The instrument of claim 4, wherein the analyzing means comprises filter means for filtering the emission spectral lines to allow only for wavelengths significant to the tissue analyte emission spectral lines to pass or to be absorbed before reaching the detector means.

8. The instrument as in claim 3, for determining blood glucose concentration continuously by non-invasive measurements of emission spectral lines characteristic to a body tissue analyte in an infrared spectral region emitted naturally by a human body'"'"'s tympanic membrane in an infrared wavelength spectrum as heat.

9. An instrument for non-invasive continuous tissue analyte concentration measurements based on measurements of emission spectral lines characteristic to a human body tissue analyte in an infrared spectral region emitted naturally by a tympanic membrane as heat, comprising:

a. an ear plug assembly for insertion into an ear canal;

b. said ear plug assembly consisting of an infrared radiation detecting system consisting of an optical infrared filter set and a detector sensitive in an infrared region of human body heat radiation for continuously detecting the emission spectral lines;

c. a base of the detector adapted to be in conductive contact with a human body;

d. said ear plug assembly connected with electronics, a microcomputer and a display system for forming, calculating, and displaying an electrical signal from the detector to show a numerical value of the analyte concentration.