Non-invasive temperature measurement

• US 20070282218A1
• Filed: 05/31/2006
• Published: 12/06/2007
• Est. Priority Date: 05/31/2006
• Status: Active Grant

• Current Assignee: Medisim Limited
• Original Assignee: Medisim Limited
• Inventors: Yarden, Moshe
• Granted Patent: US 7,597,668 B2
• Time in Patent Office: Days
• US Class Current: 600/549
• CPC Class Codes: G01K 1/165 for application in zero heat flux sensors
• CPC Class Codes: G01K 13/20 Clinical contact thermometers for use with humans or animals
• CPC Class Codes: G01K 7/42 Circuits effecting compensation of thermal inertia; Circuits for predicting the stationary value of a temperature

Abstract

A thermometric device includes a probe having a membrane configured to be applied to an external surface of a body of a subject and one or more temperature sensors located within the probe in thermal contact with the membrane. A processing unit is configured to receive temperature readings from the one or more temperature sensors, to determine time-dependent parameters of temperature change responsively to the temperature readings, to calculate a local temperature of the body using a function including the time-dependent parameters, and to calculate a core body temperature by correcting for a difference between the core body temperature and the local temperature.

Claims

1. A thermometric device, comprising:

a probe, comprising;

a membrane configured to be applied to an external surface of a body of a subject; and

one or more temperature sensors located within the probe in thermal contact with the membrane; and

a processing unit configured to receive temperature readings from the one or more temperature sensors, to determine time-dependent parameters of temperature change responsively to the temperature readings, to calculate a local temperature of the body using a function comprising the time-dependent parameters, and to calculate a core body temperature by correcting for a difference between the core body temperature and the local temperature.

2. The device according to claim 1, wherein the one or more temperature sensors comprise a plurality of temperature sensors at differing, respective thermal distances from the membrane, and wherein the processing unit is adapted to process the temperature readings responsively to the different thermal distances in order to calculate the core body temperature.

3. The device of claim 2, wherein the plurality of temperature sensors comprises at least three temperature sensors, and wherein the processing unit is configured to select a subset of the temperature sensors and to determine the local temperature of the body responsively to the temperature readings provided by the subset.

4. The device of claim 2, wherein a first of the plurality of temperature sensors has a first thermal sensitivity and a second of the plurality of temperature sensors has a second thermal sensitivity.

5. The device of claim 2, and comprising an insulating material, which is interposed between at least one of the temperature sensors and the membrane in order to define the differing thermal distances.

6. The device of claim 5, wherein the insulating material comprises a printed circuit.

7. The device of claim 2, wherein the temperature sensors comprise a first temperature sensor in proximity to the membrane and a second temperature sensor stacked on the first temperature sensor so that a thermal distance of the second temperature sensor from the membrane comprises the first temperature sensor.

8. The device of claim 1, wherein a contour of the membrane is configured so as to cause skin of the body to conform to the contour.

9. The device of claim 1, wherein the device comprises a handheld meter, and wherein the probe is attached by a joint to the handheld meter.

10. The device of claim 9, wherein the joint is flexible.

11. The device of claim 1, wherein the probe and processing unit are physically separated.

12. The device of claim 11, wherein the probe is compressible.

13. The device of claim 11, and comprising a wireless transmitter, for transmitting the temperature readings from the probe to the processing unit.

14. The device of claim 1, and comprising a pressure sensor configured to indicate that an appropriate pressure is applied between the membrane and the external surface of the body.

15. The device of claim 1, and comprising a display, to display the core body temperature.

16. The device of claim 1, wherein the probe is configured to be affixed to the external surface of the body.

17. The device of claim 16, and comprising an adhesive material for affixing the device to the body.

18. The device of claim 1, and comprising a timer to measure intervals between administrations of a medication to the subject.

19. The device of claim 1, wherein the processor is operative to calculate the core body temperature responsively to sensing a change in a temperature reading from the one or more temperature sensors.

20. The device of claim 1, wherein the probe comprises a pressure sensor, which is adapted to measure a pressure of the probe against the body surface, and wherein the processing unit is operative to use the measured pressure in determining the core body temperature.

21. A patient care device, comprising:

a probe for application to an external surface of a body of a subject, the probe comprising one or more temperature sensors for determining a temperature of the subject; and

a timer for measuring and indicating intervals between administrations of a medication to the subject.

22. A method for thermometric measurement, comprising:

applying a probe, which comprises a heat-conducting membrane and one or more temperature sensors in thermal communication with the membrane, to an external surface of a body of a subject;

receiving temperature readings from the one or more temperature sensors while the probe is applied to the surface of the body;

determining time-dependent parameters of temperature change responsively to the temperature readings;

calculating a local temperature of the body using a function comprising the time-dependent parameters; and

calculating a core body temperature by correcting for a difference between the core body temperature and the local temperature.

23. The method of claim 22, wherein the one or more temperature sensors comprise a plurality of temperature sensors at differing, respective thermal distances from the membrane, and wherein calculating the local and core body temperatures comprises processing the temperature readings responsively to the different thermal distances in order to calculate the core body temperature.

24. The method of claim 23, wherein the plurality of temperature sensors comprises at least three temperature sensors, and wherein calculating the local temperature of the body comprises selecting a subset of the temperature sensors and calculating the local temperature responsively to the temperature readings provided by the subset.

25. The method of claim 23, wherein a first of the plurality of temperature sensors has a first thermal sensitivity and a second of the plurality of temperature sensors has a second thermal sensitivity.

26. The method of claim 23, and comprising interposing between at least one of the plurality of temperature sensors and the membrane an insulating material to define the differing thermal distances.

27. The method of claim 23, wherein the temperature sensors comprise a first temperature sensor in proximity to the membrane and a second temperature sensor stacked on the first temperature sensor so that a thermal distance of the second temperature sensor from the membrane comprises the first temperature sensor.

28. The method of claim 22, wherein a contour of the membrane is configured so as to cause skin of the body to conform to the contour.

29. The method of claim 22, wherein applying the probe comprises indicating that an appropriate pressure is applied between the membrane and the external surface of the body in order to receive the temperature readings.

30. The method of claim 22, wherein applying the probe comprises using an adhesive patch to affix the probe to the body.

31. The method of claim 30, and comprising transmitting the temperature readings from the probe to a telemetry receiver.

32. The method of claim 22, and comprising measuring intervals, using the probe, between administrations of a medication to the subject.

33. The method of claim 22, wherein calculating the core body temperature comprises determining the core body temperature responsively to sensing a change in a temperature reading from the one or more temperature sensors.

34. The method of claim 22, wherein calculating the core body temperature comprises determining the core body temperature responsively to sensing a pressure change on the membrane.

35. The method of claim 22, and comprising measuring a pressure of the probe against the body surface, wherein calculating the core body temperature comprises correcting for the difference between the core body temperature and the local temperature responsively to the measured pressure.