Active pulse blood constituent monitoring

• US 6,931,268 B1
• Filed: 11/06/2000
• Issued: 08/16/2005
• Est. Priority Date: 06/07/1995
• Status: Expired due to Fees

• Current Assignee: Masimo Corporation
• Original Assignee: Masimo Laboratories, Inc. (Masimo Corporation)
• Inventors: Kiani-Azarbayjany, Esmaiel, Diab, Mohamed Kheir, Lepper, James M. Jr.
• Primary Examiner(s): Winakur, Eric F.
• Assistant Examiner(s): KREMER, MATTHEW J
• Application Number:
  US09/706,965
• Time in Patent Office: 1,744 Days
• Field of Search: 600/310, 600/322, 600/316, 600323-326, 600334-335
• US Class Current: 600/316
• CPC Class Codes: A61B 2560/0462 Apparatus with built-in sensors
• 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 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/6838 Clamps or clips

Abstract

A blood glucose monitoring system is disclosed which provides for inducing an active pulse in the blood volume of a patient. The induction of an active pulse results in a cyclic, and periodic change in the flow of blood through a fleshy medium under test. By actively inducing a change of the blood volume, modulation of the volume of blood can be obtained to provide a greater signal to noise ratio. This allows for the detection of constituents in blood at concentration levels below those previously detectable in a non-invasive system. Radiation which passes through the fleshy medium is detected by a detector which generates a signal indicative of the intensity of the detected radiation. Signal processing is performed on the electrical signal to isolate those optical characteristics of the electrical signal due to the optical characteristics of the blood.

Claims

1. A system for non-invasively monitoring concentrations of blood constituents in a living subject, said system comprising:

a light source configured to irradiate a fleshy medium at one location with radiation at a plurality of wavelengths, each wavelength selected for attenuation sensitivity to at least one of a plurality of blood constituent concentrations, said plurality of blood constituent concentrations including a glucose concentration;

an active pulse inducement device which causes a periodic change in a volume of blood in the fleshy medium with the level of inducement below a level that causes significant variations in the optical properties of the fleshy medium;

an optical detector positioned to detect light which has been attenuated by said fleshy medium at said one location, said optical detector configured to generate an output signal indicative of the intensity of said radiation after attenuation through said fleshy medium at said one location; and

a signal processor responsive to said output signal to analyze said output signal to extract portions of said signal due to optical characteristics of said blood to determine the concentration of at least one selected constituent within said subject'"'"'s bloodstream.

2. The system of claim 1, wherein the active pulse inducement device causes a periodic change in the volume of blood in the fleshy medium independent of the natural flow of blood in said fleshy medium.

3. The system of claim 1, further comprising a receptacle which receives said fleshy medium, said receptacle further having an inflatable bladder.

4. The system of claim 1, wherein the change in fluid volume within the fleshy medium is induced at a location distal from said one a location of the irradiation.

5. A system for non-invasively monitoring concentrations of blood constituents in a living subject, said system comprising;

a light source configured to irradiate a fleshy medium with radiation at a plurality of wavelengths, each wavelength selected for attenuation sensitivity to at least one of a plurality of blood constituent concentrations, said plurality of blood constituent concentrations including a glucose concentration;

an active pulse inducement device which causes a periodic change in a volume of blood in the fleshy medium with the level of inducement below a level that causes significant variations in the optical properties of the fleshy medium;

an optical detector positioned to detect light which has been attenuated by said fleshy medium, said optical detector configured to generate an output signal indicative of the intensity of said radiation after attenuation through said fleshy medium; and

a signal processor responsive to said output signal to analyze said output signal to extract portions of said signal to optical characteristics of said blood to determine the concentration of at least one selected constituent within said subject'"'"'s bloodstream, wherein the active pulse inducement device causes a periodic change in the volume of blood in the fleshy medium in conjunction with the natural flow of blood in said fleshy medium.

6. A system for non-invasively monitoring concentrations of blood constituents in a living subject, said system comprising:

a light source configured to irradiate a fleshy medium with radiation at a plurality of wavelengths, each wavelength selected for attenuation sensitivity to at least one of a plurality of blood constituent concentrations, said plurality of blood constituent concentrations including a glucose concentration;

an active pulse inducement device which causes a periodic change in a volume of blood in the fleshy medium with the level of inducement below a level that causes significant variations in the optical properties of the fleshy medium;

an optical detector positioned to detect light which has been attenuated by said fleshy medium, said optical detector configured to generate an output signal indicative of the intensity of said radiation after attenuation through said fleshy medium;

a signal processor responsive to said output signal to analyze said output signal to extract portions of said signal due to optical characteristics of said blood to determine the concentration of at least one selected constituent within said subject'"'"'s bloodstream; and

a receptacle which receives said fleshy medium, said receptacle further comprising a temperature variation element, said temperature variation element cyclicly varying the temperature of said fleshy medium in order to induce a change in the flow of blood in said fleshy medium.

7. A system for non-invasively monitoring concentrations of blood constituents in a living subject, said system comprising;

a light source configured to irradiate a fleshy medium at a test site on a living subject, wherein the irradiation includes radiation at a plurality of wavelengths selected for attenuation sensitivity to at least one of a plurality of blood constituent concentrations including a glucose concentration;

an active pulse inducement device configured to induce at a location other than the test site a change in a volume of fluid in the fleshy medium, thereby reducing variations in optical properties of the fleshy medium at the test site while still showing at least some effect of the change in the volume at the test site;

an optical detector positioned to detect light which has been attenuated by said fleshy medium at the test site, and configured to generate an output signal based only on the light detected at the test site; and

a signal processor responsive to said output signal to analyze said output signal to extract portions of said output signal due to optical characteristics of said blood to determine the concentration of at least one selected constituent within said living subject'"'"'s bloodstream.

8. The system of claim 7, wherein the active pulse inducement device causes a periodic change in the volume of blood.

9. The system of claim 7, wherein the active pulse inducement device causes a periodic change in the volume of blood independent of a natural flow of blood.

10. The system of claim 7, further comprising a receptacle which receives said fleshy medium, and receptacle further having an inflatable bladder.

11. A system for non-invasively monitoring concentrations of blood constituents in a living subject, said system comprising:

a light source configured to irradiate a fleshy medium at a test site on a living subject, wherein the irradiation includes at a plurality of wavelengths selected for attenuation sensitivity to at least one of a plurality of blood constituent concentrations including a glucose concentration;

an active pulse inducement device configured to induce at a location other than the test site a chance in a volume of fluid in the fleshy medium, thereby reducing variations in optical properties of the fleshy medium at the test site while still showing at least some effect of the change in the volume at the test site;

an optical detector positioned to detect light which has been attenuated by said fleshy medium, and configured to generate an output signals; and

a signal processor responsive to said output signal to analyze said output signal to extract portions of said output signal due to optical characteristics of said blood to determine the concentration of at least one selected constituent within said living subject'"'"'s bloodstream, wherein the active pulse inducement device causes a periodic change in the volume of blood in conjunction with a natural flow of blood.

12. A system for non-invasively monitoring concentrations of blood constituents in a living subject, said system comprising:

a light source configured to irradiate a fleshy medium at a test site on a living subject, wherein the irradiation includes radiation at a plurality of wavelengths selected for attenuation sensitivity to at least one of a plurality of blood constituent concentrations including a glucose concentration;

an active pulse inducement device configured to induce at a location other than the test site a change in a volume of fluid in the fleshy medium, thereby reducing variations in optical properties of the fleshy medium at the test site while still showing at least some effect of the change in the volume at the test site;

an optical detector positioned to detect light which has been attenuated by said fleshy medium, and configured to generate an output signal;

a signal processor responsive to said output signal to analyze said output signal to extract portions of said output signal due to optical characteristics of said blood to determine the concentration of at least one selected constituent within said living subject'"'"'s bloodstream; and

a receptacle which receives said fleshy medium, said receptacle further comprising a temperature variation element, said temperature variation element cyclicly varying the temperature of said fleshy medium in order to induce a change in the flow of blood in said fleshly medium.

13. A system for non-invasively monitoring concentrations of blood constituents in a living subject, said system comprising:

an input which accepts a signal output from an optical detector positioned to detect light only at a first area which has been attenuated by a fleshy medium of a living subject, said signal including effects of an non-natural active change in a volume of fluid in the fleshy medium, said non-natural active change being induced at a second area on the fleshy medium different from the first area at a level that does not cause significant variations in the optical properties of the first area, wherein the light comprises a plurality of wavelengths, each wavelength selected for attenuation sensitivity to at least one of a plurality of constituent concentrations, said plurality of constituent concentrations including a glucose concentration; and

a signal processor responsive to said signal to extract portions of said signal due to optical characteristics of said fluid to determine the concentration of at least one selected constituent within said subject'"'"'s bloodstream.

14. A sensor and inducement system for outputting a signal indicative of concentrations of blood constituents in a living subject, said system comprising:

a light source configured to irradiate a fleshy medium at a test site on a living subject at a plurality of wavelengths selected for attenuation sensitivity to at least one of a plurality of blood constituent concentrations including a glucose concentration;

an active pulse inducement device configured to induce at a location other than the test site a change in a volume of fluid in the fleshy medium, thereby reducing variations in optical properties of the fleshy medium at the test site while still showing at least some effect of the change in the volume at the test site; and

an optical detector positioned to detect only light which has been attenuated by said fleshy medium at said test site and configured to generate an output signal based only on the light detected at said test site.