Estimation of Human Core Temperature based on Heart Rate System and Method

• US 20140180027A1
• Filed: 12/16/2013
• Published: 06/26/2014
• Est. Priority Date: 12/20/2012
• Status: Abandoned Application

• Current Assignee: US Department of The Army (Government of the United States of America), U.S. Army Medical Research And Materiel Command
• Original Assignee: U.S. Government
• Inventors: Buller, Mark J.
• Application Number:
  US14/107,920
• Publication Number:
  US 20140180027A1
• Time in Patent Office: Days
• US Class Current: 600/301
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/725 using specific filters therefor, e.g. Kalman or adaptive filters A61B5/316 take precedence

Abstract

The invention in at least one embodiment includes a method for determining the core body temperature of a person by setting an initial core body temperature with a processor; receiving a heart rate of the person with the processor; calculating a predicted core body temperature with the processor using an extended Kalman filter based on the heart rate and the initial core body temperature; and providing the predicted core body temperature. In another embodiment, a system for performing the method.

Claims

1. A method for determining the core body temperature of a person comprising:

setting an initial core body temperature with a processor;

receiving a heart rate of the person with the processor;

calculating a predicted core body temperature with the processor using an extended Kalman filter based on the heart rate and the initial core body temperature; and

providing the predicted core body temperature.

5. The method according to claim 1, wherein providing the predicted core body temperature includes displaying the predicted core body temperature.

6. The method according to claim 1, wherein providing the predicted core body temperature includes transmitting the predicted core body temperature with a transmitter to an external device.

7. The method according to claim 1, wherein calculating a predicted core body temperature includes calculating a preliminary core body temperature;

calculating a preliminary estimate of the variance of a core body temperature estimate;

calculating an extended Kalman filter mapping function variance coefficient;

calculating a Kalman gain weighting factor based on the preliminary estimate of variance and the extended Kalman filter variance coefficient; and

calculating the predicted core body temperature using a preliminary time-update estimate, an error between the new heart rate and an expected heart rate given the preliminary estimate of the core body temperature.

8. The method according to claim 7, wherein calculating a predicted core body temperature further includes determining a variance of the predicted core body temperature.

9. The method according to claim 1, further comprising adjusting the extended Kalman filter based on at least one of a fitness level, an age, a maximum heart rate and a resting heart rate of the person.

2. The method according to claim 2, further comprising:

receiving another heart rate of the person with the processor;

calculating a new predicted core body temperature using the extended Kalman filter based on the another heart rate and the last predicted core body temperature; and

repeating the receiving another heart rate and calculating a new predicted core body temperature at predetermined intervals.

3. The method according to claim 2, further comprising:

when the new predicted core body temperature exceeds a predetermined threshold, sending an alarm signal prior to proceeding to repeating, wherein the alarm signal triggers an alarm; and

when the new predicted core body temperature does not exceed a predetermined threshold, proceeding to repeating.

4. The method according to claim 2, further comprising obtaining the predetermined interval.

10. A system comprising:

a heart rate data source; and

a processor in communication with said heart rate data source, said processor capable of calculating a core body temperature based on constants and having as the only inputs heart rate information and prior core body temperature data.

11. The system according to claim 10, further comprising a display in communication with said processor.

12. The system according to claim 10, further comprising a transmitter for communication with an external system, said transmitter in communication with said processor.

13. The system according to claim 10, further comprising a temperature sensor in communication with said processor.

14. The system according to claim 10, wherein said processor includes

an initial core body temperature module for setting an initial core body temperature,

a heart rate module for obtaining heart rate information, and

a core body temperature calculator in communication with said initial core body temperature module and said heart rate module.

15. The system according to claim 14, where said processor further includes a timer module in communication with said heart rate module and said core body temperature calculator.

16. The system according to claim 15, where said processor further includes an alarm module in communication with said core body temperature calculator.

17. The system according to claim 16, further comprising:

a display in communication with said core body temperature calculator;

a transmitter in communication with said core body temperature calculator; and

a temperature sensor in communication with at least one of said timer module and said alarm module.

18. A system comprising:

a heart rate data source; and

a processor in communication with said heart rate data source, said processor having program code embodied therewith, the program code executable by the processor to

set an initial core body temperature;

receive a heart rate of the person;

calculate a predicted core body temperature using an extended Kalman filter having as inputs the heart rate and the initial core body temperature; and

provide the predicted core body temperature.

19. The system according to claim 18, further comprising:

a display in communication with said core body temperature calculator; and

a transmitter in communication with said core body temperature calculator.

20. The system according to claim 18, wherein the initial core body temperature is set based on the initial heart rate of the person.