Method and device for non-invasive measurements of blood parameters

• US 20070043281A1
• Filed: 08/17/2005
• Published: 02/22/2007
• Est. Priority Date: 08/17/2005
• Status: Active Grant

• Current Assignee: OrSense Ltd.
• Original Assignee: OrSense Ltd.
• Inventors: Fine, IIya
• Granted Patent: US 7,254,432 B2
• Time in Patent Office: Days
• US Class Current: 600/335
• CPC Class Codes: A61B 5/0048 Detecting, measuring or recording by applying mechanical forces or stimuli A61B5/021, A61B5/4884 and A61B9/00 take precedence
• CPC Class Codes: A61B 5/0095 by applying light and detecting acoustic waves, i.e. photoacoustic measurements
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/6838 Clamps or clips

Abstract

A method and system for non-invasive measurements in a patient'"'"'s body in which several measurement sessions are performed on a measurement location. Each measurement session includes applying an external electromagnetic field to the measurement locations, detecting at least two responses of the measurement location, and generating data indicative of the detected response. These responses are characterized by at least two different values of a controllable parameter. The measurement sessions include at least two measurement sessions carried out at a normal blood flow in the measurement location and at least two measurement sessions carried out at a condition of artificial kinetics in the measurement location. The first and second measured data are processed to determine a first relation between the first time variations and a second relation between the second time variations for the different parameter that can be used to determine the at least one blood related parameter.

Claims

1. A method for use in non-invasive measurements in a patient'"'"'s body, the method comprising:

(a) performing several measurement sessions on a measurement location on the body, each measurement session comprising applying an external electromagnetic field to a measurement location and detecting at least two responses of the measurement location characterized by at least two different values of a controllable parameter, and generating data indicative of the detected response, wherein the measurement sessions include at least two measurement sessions carried out at a first condition of normal blood flow in the measurement location enabling generation of first measured data indicative of a first time variation of the response for each of said at least two parameter values, and at least two measurement sessions carried out at a second condition of artificial kinetics in the measurement location enabling generation of second measured data indicative of a second time variation of the response for each of said at least two parameter values; and

(b) processing the first measured data to determine a first relation between the first time variations for the different parameter values and processing the second measured data to determine a second relation between the second time variations for said different parameter values; and

(c) utilizing the first and second relations to determine a certain function between said first and second relations, said certain function being indicative of at least one blood related parameter.

2. The method of claim 1, wherein the condition of artificial kinetics is created by applying over-systolic pressure at the measurement location, or to a location on the body upstream of the measurement location with respect to a normal blood flow direction in the body.

3. The method of claim 1, wherein each of the measurement sessions includes more than two wavelengths of illumination.

4. The method of claim 1, wherein the measurement session includes illuminating the measurement location with at least two different wavelengths of light and detecting the light response of the body portion under measurements.

5. The method of claim 4, wherein the light response includes light transmitted through and/or scattered from the body portion.

6. The method of claim 1, wherein each of the first and second relations is determined as a parametric slope of the respective time functions of the responses.

7. The method of claim 4, wherein each of the first and second relations is determined as a parametric slope of the respective time functions of the responses.

8. The method of claim 7, wherein a pair of the first and second parametric slopes PS₁ and PS₂ obtained for the same pair of wavelengths λ

₁-λ

₂ are determined as

9. The method of claim 7, wherein the desired blood parameter BP is determined as

10. The method of claim 1, wherein said at least two measurement sessions carried out at the normal blood flow condition are carried out either prior to said at least two measurement sessions under the artificial kinetics condition, or thereafter.

11. The method of claim 1, wherein said at least one blood related parameter includes one of a concentration of substance in blood and oxygen saturation.

12. The method of claim 11, wherein said substance includes at least one of the following:

hemoglobin, hematocrit, glucose.

13. A method for use in non-invasive measurements in a patient'"'"'s body, the method comprising:

(a) performing several optical measurement sessions on a measurement location on the body, each measurement session comprising illuminating a measurement location and detecting light responses of the measurement location characterized by at least two different values of a controllable parameter, and generating data indicative of the detected light response, wherein the measurement sessions include at least two measurement sessions carried out at a first condition of normal blood flow in the measurement location enabling generation of first measured data indicative of a first time variation of the light response for each of said at least two parameter values, and at least two measurement sessions carried out at a second condition of artificial kinetics in the measurement location enabling generation of second measured data indicative of a second time variation of the light response for each of said at least two parameter values; and

(b) processing the first measured data to determine a first relation between the first time variations for the different parameter values and processing the second measured data to determine a second relation between the second time variations for said different parameter values; and

(c) utilizing the first and second relations to determine a certain function between said first and second relations, said certain function being indicative of at least one blood related parameter.

14. A device for use in non-invasive measurements in a patient'"'"'s body, the device comprising:

(a) a measurement unit comprising an electromagnetic field source assembly configured and operable for applying an external electromagnetic field to a measurement location on the body, and a detector arrangement configured and operable for detecting a response of the measurement location to the applied field and generating data indicative thereof;

(b) a pressure applying assembly configured and operable for applying over-systolic pressure to the body portion so as to create a condition of artificial kinetics in the measurement location characterized by a blood flow cessation;

(c) a control unit connectable to the measurement unit and to the pressure applying assembly for operating them so as to enable several measurement sessions on the measurement location, each measurement session carried out with at least two different values of a controllable parameter, such that the measurement sessions include at least two measurement sessions carried out at a first condition of normal blood flow in the measurement location with no application of pressure and at least two measurement sessions carried out at the second condition of artificial kinetics in the measurement location;

the control unit being configured for receiving and processing said data indicative of the response of the measurement location to the applied field to determine first measured data indicative of a first time variation of the response for each of said at least two parameter values while at the normal blood flow condition and second measured data indicative of a second time variation of the response for each of said at least two parameter values while at the artificial kinetics condition, thereby enabling determination of a first relation between the first time variations for the different parameter values and a second relation between the second time variations for said different parameter values, and utilizing said first and second relations to determine a certain function between said first and second relations, said certain function being indicative of at least one blood related parameter.

15. The device of claim 14, wherein said field source includes a light source and said detector unit includes a light detector.

16. The device of claim 14, wherein the control unit operates the measurement unit and the pressure applying assembly such that said at least two measurement sessions carried out at the normal blood flow condition are performed either prior to said at least two measurement sessions under the artificial kinetics condition, or thereafter.

17. The device of claim 14, wherein the control unit is preprogrammed to determine each of the first and second relations as a parametric slope of the respective time functions of the responses.

18. The device of claim 15, wherein the control unit is preprogrammed to determine each of the first and second relations as a parametric slope of the respective time functions of the responses.

19. The device of claim 18, wherein the control unit is preprogrammed to determine a pair of the first and second parametric slopes PS₁ and PS₂ for the same pair of wavelengths λ

₁-λ

₂ as;

20. The device of claim 18, wherein the control unit is preprogrammed to utilize the first and second parametric slopes to determine the desired blood parameter BP as