Substance Concentration Monitoring Apparatuses and Methods

• US 20150366490A1
• Filed: 06/19/2015
• Published: 12/24/2015
• Est. Priority Date: 06/19/2014
• Status: Active Grant

• Current Assignee: GlucoVista, Inc.
• Original Assignee: GlucoVista, Inc.
• Inventors: Gerlitz, Yonatan, Landa, Efraim
• Granted Patent: US 10,617,337 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 5/0022 Monitoring a patient using a global network, e.g. telephone networks, internet
• 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 5/1491 Heated applicators
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/746 Alarms related to a physiological condition, e.g. details of setting alarm thresholds or avoiding false alarms alarms per se G08B
• CPC Class Codes: A61B 5/747 in case of emergency, i.e. alerting emergency services

Abstract

A substance concentration monitoring method includes inducing a periodic change in a body surface temperature over time using a heating and/or cooling element and yielding a function of temperature that varies with time so as to exhibit a temperature derivative with respect to time that oscillates periodically. Mid-infrared radiation absorbed or emitted from the body is measured while the surface of the body exhibits the oscillating, periodic derivative. The method includes determining a measured value based on the MIR radiation measurements and determining a concentration of a substance in the body based on a correlation with the measured value. A substance concentration monitoring apparatus includes a processor that initiates operations continuously monitoring whether the concentration or the measured value are within a tolerance. The operations further include generating a warning output when the concentration or the measured value is outside the tolerance.

Claims

1. A substance concentration monitoring method comprising

inducing a periodic change in a temperature (T) of a surface of a body over time (t) using a heating and/or cooling element according to a periodic signal received by the element and yielding a function of temperature (T) that varies with time (t) so as to exhibit a temperature derivative with respect to time (dT/dt) that oscillates periodically;

measuring mid-infrared (MIR) radiation absorbed or emitted from the body while the surface of the body exhibits the oscillating, periodic dT/dt;

determining a measured value based on the MIR radiation measurements; and

determining a concentration of a substance in the body based on a correlation with the measured value.

2. The method of claim 1, wherein the measured value is also based on the oscillating, periodic dT/dt.

3. The method of claim 2, wherein the measured value is correlated with glucose concentration.

4. The method of claim 1, wherein measuring IR radiation comprises:

measuring the MIR radiation at a temperature during a positive dT/dt (an upward sloping temperature change); and

measuring the MIR radiation at the same temperature during a negative dT/dt (a downward sloping temperature change).

5. The method of claim 1, wherein measuring IR radiation comprises:

measuring a first MIR radiation at a temperature during a positive dT/dt (an upward sloping temperature change), the measuring occurring within a first wavelength band in which the substance has an effect on MIR emission or absorption;

measuring a first reference MIR radiation at the temperature during the positive dT/dt, the measuring occurring within a second wavelength band in which the substance has no or negligible effect on MIR emission or absorption;

measuring a second MIR radiation at the temperature during a negative dT/dt (a downward sloping temperature change), the measuring occurring within the first wavelength band; and

measuring a second reference IR radiation at the temperature during the negative dT/dt, the measuring occurring within the second wavelength band.

6. The method of claim 5, wherein determining the measured value comprises including the first and second MIR radiation measurements and the first and second reference MIR radiation measurements in an equation that yields the measured value and the method further comprises generating a correlation of the measured value with the substance concentration.

7. The method of claim 1, further comprising determining dT/dt at the time the MIR radiation is measured and including dT/dt in the measured value that is correlated with the substance concentration.

8. A substance concentration monitoring apparatus comprising:

a processor;

a heating and/or cooling element;

an infrared sensor; and

a memory accessible to the processor, the memory storing instructions that, when executed by the processor, cause the processor to initiate operations including;

generating a periodic signal configured to control the heating and/or cooling element and thereby to induce a periodic change in a temperature (T) of a surface of a body over time (t) and to yield a function of temperature (T) that varies with time (t) so as to exhibit a temperature derivative with respect to time (dT/dt) that oscillates periodically;

collecting data from the infrared sensor while the surface of the body exhibits the oscillating, periodic dT/dt, the data resulting from a measurement of mid-infrared (MIR) radiation absorbed or emitted from the body within a first wavelength band in which a substance has an effect on MIR emission or absorption and a measurement of MIR reference radiation absorbed or emitted from the body within a second wavelength band in which the substance has no or negligible effect on MIR emission or absorption;

determining a measured value based on the MIR radiation data and the MIR reference radiation data; and

determining a concentration of the substance in the body based on a correlation with the measured value.

9. The apparatus of claim 8, wherein the processor operations further comprise:

monitoring the concentration of the substance in the body by determining whether the concentration or the measured value are within a tolerance; and

generating a warning output when the concentration or the measured value is outside the tolerance.

10. The apparatus of claim 9, further comprising a wireless transmitter, wherein the processor operations further include sending the warning output to a remote device via the wireless transmitter to display a warning.

11. The apparatus of claim 10, wherein the remote device includes a mobile telephone and the warning output indicates that the remote device is to contact an emergency service.

12. The apparatus of claim 8, wherein the measured value is also based on the oscillating, periodic dT/dt.

13. The apparatus of claim 12, wherein the measured value is correlated with glucose concentration.

14. The apparatus of claim 8, wherein collecting the data from the infrared sensor comprises:

collecting the data at a temperature during a positive dT/dt (an upward sloping temperature change); and

collecting the data at the same temperature during a negative dT/dt (a downward sloping temperature change).

15. The apparatus of claim 14, wherein determining the measured value comprises including the MIR radiation data and the MIR reference radiation data collected during both the positive and the negative dT/dt in an equation that yields the measured value.

16. The apparatus of claim 14, wherein the periodic signal is configured to produce a constant rate of change in temperature (dT/dt) of the heating and/or cooling element during both the positive and the negative dT/dt.

17. The apparatus of claim 8, wherein collecting the data further comprises determining dT/dt at the time the MIR radiation is measured and determining the measured value further comprises including dT/dt in the measured value that is correlated with the substance concentration.

18. The apparatus of claim 8, wherein the periodic signal is configured to produce a periodic temperature pattern of the heating and/or cooling element that corresponds to a square wave, a triangle wave, a sinusoidal wave, or a combination thereof.

19. A substance concentration monitoring apparatus comprising:

a processor; and

a memory accessible to the processor, the memory storing instructions that, when executed by the processor, cause the processor to initiate operations including;

generating a consecutive plurality of data parameters indicative of respective concentrations of a substance in a body based on a corresponding plurality of mid-infrared (MIR) measurement sets, each MIR measurement set of the plurality of MIR measurement sets including a MIR measurement of the surface of the body within a first wavelength band in which the substance has an effect on MIR emission or absorption and a MIR measurement of the surface of the body within a second wavelength band in which the substance has no or negligible effect on MIR emission or absorption;

continuously monitoring the concentrations of the substance in the body by determining whether the concentrations or the consecutive plurality of data parameters are within a tolerance; and

generating a warning output when one or more of the concentrations or one or more of the consecutive plurality of data parameters is outside the tolerance.

20. The apparatus of claim 19, further comprising a ring-shaped heating and/or cooling element, wherein the operations further include changing a temperature at the ring-shaped heating and/or cooling element according to a periodic signal.

21. The apparatus of claim 20, wherein each MIR measurement set of the plurality of MIR measurement sets corresponds to a respective period of the periodic signal.

22. The apparatus of claim 21, wherein a period of the periodic signal is 60 seconds.

23. The apparatus of claim 21, wherein each MIR measurement set of the plurality of MIR measurement sets is taken during a portion of the periodic signal configured to produce a constant rate of change in temperature of the ring-shaped heating and/or cooling element.

24. The apparatus of claim 21, wherein the periodic signal is configured to produce a periodic temperature pattern of the ring-shaped heating and/or cooling element that corresponds to a square wave, a triangle wave, a sinusoidal wave, or a combination thereof.

25. The apparatus of claim 19, further comprising an attachment mechanism configured to attach to the body, wherein the operations include recording the plurality of MIR measurement sets while the attachment mechanism is attached to the body.

26. The apparatus of claim 19, further comprising at least one MIR detector and a transmission window structure, wherein the MIR measurement of the surface of the body within the first wavelength band and the MIR measurement of the surface of the body within the second wavelength band are detected at the MIR detector via the transmission window structure.

27. The apparatus of claim 19, further comprising a wireless transmitter, wherein the operations further include sending the warning output to a remote device via the wireless transmitter to display a warning.

28. The apparatus of claim 27, wherein the remote device includes a mobile telephone and the warning output indicates that the remote device is to contact an emergency service.

29. The apparatus of claim 19, wherein the operations further comprise calculating a continuous correlation function based on the plurality of data parameters and reducing noise and/or measurement variations in the plurality of MIR measurement sets.

30. A substance concentration monitoring method comprising:

attaching a continuous monitoring apparatus to a body;

generating a consecutive plurality of data parameters indicative of respective concentrations of a substance in a body based on a corresponding plurality of mid-infrared (MIR) measurement sets collected with the continuous monitoring apparatus fastened to the body, each MIR measurement set of the plurality of MIR measurement sets including a MIR measurement of the surface of the body within a first wavelength band in which the substance has an effect on MIR emission or absorption and a MIR measurement of the surface of the body within a second wavelength band in which the substance has no or negligible effect on MIR emission or absorption;

continuously monitoring the concentrations of the substance in the body by determining whether the concentrations or the consecutive plurality of data parameters are within a tolerance; and

generating a warning output when one or more of the concentrations or one or more of the consecutive plurality of data parameters is outside the tolerance.

31. The method of claim 30, further comprising changing a temperature of the surface of the body according to a periodic pattern generated by a heating and/or cooling element.

32. The method of claim 31, wherein each MIR measurement set of the plurality of MIR measurement sets corresponds to a respective period of the periodic pattern.

33. The method of claim 31, wherein each MIR measurement set of the plurality of MIR measurement sets is taken during a portion of the periodic pattern that has a constant rate of change in temperature.

34. The method of claim 30, wherein the plurality of MIR measurements are taken without removing the wearable apparatus from the body.

35. The method of claim 34, wherein the plurality of MIR measurements are taken over a time of greater than 1 hour.

36. The method of claim 30, wherein each MIR measurement set of the plurality of MIR measurement sets further includes a MIR measurement of a blackbody device within the first wavelength band and a MIR measurement of a blackbody device within the second wavelength band.

37. A substance concentration monitoring apparatus comprising:

a housing;

at least one MIR detector attached to the housing;

a ring-shaped heating and/or cooling element attached to the housing;

a thermally conductive ring in thermal communication with the ring-shaped heating and/or cooling element;

a transmission window structure attached to the housing such that a line of sight of the MIR detector passes through the transmission window structure, a surface of the transmission window structure, and a surface of the thermally conductive ring being aligned along a same plane outside the housing.

38. The apparatus of claim 37, further comprising a rotatable filter wheel containing:

a first filter that passes light in a first wavelength band; and

a second filter that passes light in a second wavelength band, a line of sight of the MIR detector selectively passing through the first filter or the second filter as the filter wheel rotates.

39. The apparatus of claim 38, wherein the filter wheel is configured to rotate at about 20 rotations per minute and the MIR detector is configured to sample MIR emission or absorption at least 5 times through each filter as the filter wheel rotates.

40. The apparatus of claim 37, wherein the transmission window structure comprises germanium, silicon, or both.

41. The apparatus of claim 37, further comprising an attachment device configured to attach the monitoring apparatus to a surface of a body, the transmission window structure and the thermally conductive ring being configured to simultaneously contact the surface of the body when the monitoring apparatus is attached.