Method, system and device for noninvasive core body temperature monitoring
A core body temperature monitoring apparatus placed superdermally over a user's skin, including a first temperature sensor, a second temperature sensor, a thermal insulation layer positioned intermediate the first and second temperature sensor and a heater for heating the apparatus and a subdermal tissue region underlying the user's skin. The subdermal tissue region is configured with variable thermal tissue parameters. A controller includes a switch configured for alternating between a calibration mode, wherein the heater is activated for calculating an instantaneous thermal tissue parameter, and a measurement mode, wherein the heater is inactive and the core body temperature is determined, based on the calculated instantaneous thermal tissue parameter.
1. A core body temperature monitoring apparatus configured to be placed superdermally over a user's skin, comprising:
a first temperature sensor positioned in proximity to the skin;
a second temperature sensor;
a thermal insulation layer positioned intermediate the first and second temperature sensors and having a thermal conductivity constant;
the first temperature sensor being configured for detecting a temperature in proximity to the skin, and the second temperature sensor being configured for detecting a temperature above the thermal insulation layer;
a heater for heating the apparatus and a subdermal tissue region underlying the user's skin, said subdermal tissue region configured with at least one variable thermal tissue parameter; and
a controller comprising a switch, the switch configured for alternating between a calibration mode, and a measurement mode;
wherein the controller is configured in the calibration mode to:
activate the heater for generating an isothermal channel so that the temperature measured by the first temperature sensor equals the temperature measured by the second temperature sensor and to determine an instantaneous calibration subdermal temperature,
deactivate the heater for creating a heat flow channel intermediate the first temperature sensor and the second temperature sensor, and
calculate the variable thermal tissue parameter based on the calculated instantaneous calibration subdermal temperature and the detected temperature measured by the first temperature sensor and by the second temperature sensor; and
wherein the controller is configured in the measurement mode to:
determine the core body temperature based on the variable thermal tissue parameter, the thermal conductivity constant and detected temperatures, measured by the first temperature sensor and by the second temperature sensor.
2. An apparatus according to claim 1 , and further comprising a communication port for transmitting the determined core body temperature to an external device.
3. An apparatus according to claim 2 , wherein the communication between the apparatus and the external device is via Cloud communication.
4. An apparatus according to claim 1 , and further comprising a battery for supplying power to the heater, wherein the battery has a capacity in a range of at least 500-10,000 milliampere-hour (mAh) and the battery is configured to allow the apparatus to be used remotely, away from an electrical grid.
5. An apparatus according to claim 1 , wherein the first temperature sensor, the second temperature sensor, the thermal insulation layer, and the heater are disposable and the controller is reusable.
6. An apparatus according to claim 1 , wherein the heater is positioned at least at one of the following positions: (i) intermediate the first temperature sensor and the second temperature sensor, (ii) below the first temperature sensor and (iii) above the second temperature sensor.
7. An apparatus according to claim 1 , wherein the heater is positioned within the thermal insulation layer.
8. An apparatus according to claim 1 , wherein the apparatus comprises a plurality of heaters.
9. An apparatus according to claim 1 , further comprising a housing and a peripheral thermal insulation layer.
10. An apparatus according to claim 1 , wherein the controller is embedded within a peripheral thermal insulation layer.
11. An apparatus according to claim 1 , wherein a heart rate monitor is provided to verify physical coupling of the apparatus to the user's epidermis surface.
12. An apparatus according to claim 1 , further comprising at least one of an environmental sensor and a bodily function sensor.
13. An apparatus according to claim 1 , wherein the controller has operating thereon processor instructions for causing the switch to alternate between the calibration mode and the measurement mode based on at least one of:
a predetermined duration from a previous core body measurement;
a change in an environmental condition; and
a change in a physical condition of the user.