Temperature-measuring device with function indicator

• US 7,410,291 B2
• Filed: 06/27/2006
• Issued: 08/12/2008
• Est. Priority Date: 08/11/2005
• Status: Active Grant

• Current Assignee: Dragerwerk AG & Company KGaA (FPS Vermögensverwaltung GmbH)
• Original Assignee: Drager Medical AG & Co KG (Dragerwerk AG)
• Inventors: Koch, Jochim
• Primary Examiner(s): Verbitsky; Gail
• Application Number:
  US11/426,670
• Publication Number:
  US 20070038141A1
• Time in Patent Office: 777 Days
• Field of Search: 374/4, 374 43- 45, 374/57, 374100- 14, 374109-112, 374/163, 374/170, 600/549, 600/474, 702/139
• US Class Current: 374/163
• CPC Class Codes: G01K 1/20 Compensating for effects of temperature changes other than those to be measured, e.g. changes in ambient temperature
• 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
• CPC Class Codes: G01K 7/427 Temperature calculation based on spatial modeling, e.g. spatial inter- or extrapolation

Abstract

A function indicator for a dual temperature sensor, which indicates the falling off of the sensor from the skin surface (4) of a patient. An evaluating device (2) determines the body temperature from a first measured temperature value (T_A) and determines the contact of the dual temperature sensor (1) with the skin surface (4) by comparison of the measured temperature values T_A and T_B.

Claims

1. A temperature-measuring device comprising:

a first temperature sensor;

a second temperature sensor, said first temperature sensor and said second temperature sensor being arranged opposite each other to form a dual temperature sensor, wherein one of said first temperature sensor or said second temperature sensor is in contact with a skin surface of a patient for detecting a first measured temperature value T_A and the other of said first temperature sensor and said second temperature sensor is arranged opposite and detects a second measured temperature value T_b thermally coupled with the temperature in the environment of the skin surface;

an evaluating means for determining the body temperature of the patient from said first measured temperature value T_A and determining whether said dual temperature sensor is in contact with said skin surface by comparing said measured temperature value T_A with said measured temperature value T_B and using a rate of change of said measured temperature value T_A and a rate of change of said measured temperature value T_B to indicate whether said dual temperature sensor is in contact with said skin surface.

2. A temperature-measuring device in accordance with claim 1, wherein said evaluating means calculates a body core temperature from said measured temperature values T_A, T_B.

3. A temperature-measuring device in accordance with claim 1, wherein said evaluating means forms a sum and a difference from said measured temperature values T_A, T_B compares the changes over time in the sum and the difference with respect to similar rates of change of the signals as an indicator of the contact of said dual temperature sensor with said skin surface.

4. A temperature-measuring device in accordance with claim 3, wherein said evaluating means determines the the rates change of said signals from Pearson'"'"'s correlation coefficient.

5. A temperature-measuring device in accordance with claim 1, wherein said dual temperature sensor is not in contact with said skin surface when said rate of change of said first measured temperature value T_A is similar to said rate of change of said second measured temperature value T_B.

6. A temperature-measuring device in accordance with claim 1, wherein said first temperature sensor has a first thermal conductivity and said second temperature sensor has a second thermal conductivity, said second thermal conductivity being different from said first thermal conductivity.

7. A temperature-measuring device in accordance with claim 1, further comprising an alarm means for indicating when said dual temperature sensor is not in contact with said skin surface.

8. A temperature-measuring device comprising:

a patient skin temperature sensor having a first thermal conductivity;

an environment temperature sensor having a second thermal conductivity, said first thermal conductivity being different from said second thermal conductivity, said patient skin temperature sensor and said environment temperature sensor being arranged opposite each other, wherein said patient skin temperature sensor is in contact with the skin surface of a patient during use for detecting a patient skin measured temperature value over time and said environment temperature sensor is arranged opposite thereto and detects an environment measured temperature value over time;

an evaluating device for determining the body temperature of the patient from the patient skin measured temperature value and for determining the status of the contact of the patient skin temperature sensor with the skin surface of the patient by comparing a time rate of change of the patient skin measured temperature value with a time rate of change of the environment measured temperature value, said evaluating device providing as output an alarm signal when said time rate of change of the patient skin measured temperature value is substantially equal to said time rate of change of the environment measured temperature value.

9. A temperature-measuring device in accordance with claim 8, wherein said patient skin temperature sensor is not in contact with said skin surface when said rate of change of said patient skin temperature sensor is substantially similar to said rate of change of said environment temperature sensor.

10. A temperature-measuring device in accordance with claim 8, further comprising an alarm means for receiving said alarm signal and providing as output an alert.

11. A temperature-measuring device in accordance with claim 8, wherein said evaluating device calculates a body core temperature from said patient skin measured temperature value and said environment measured temperature value.

12. A temperature-measuring device in accordance with claim 8, wherein said evaluating device forms a sum and a difference from said patient skin measured temperature value and said environment measured temperature value and compares the changes over time in the sum and the difference with respect to the similar rates of change of the signals as an indicator of the contact of the patient skin temperature sensor with said skin surface.

13. A temperature-measuring device in accordance with claim 12, wherein said evaluating device determines the rates of change of the signals of said patient skin temperature sensor and environment temperature sensor by forming a Pearson'"'"'s correlation coefficient from the sum and the difference.

14. A temperature-measuring method comprising the steps of:

providing a patient skin temperature sensor with an environment temperature sensor at an opposite side;

placing the patient skin temperature sensor in contact with the skin surface of a patient so the opposite side is positioned thermally coupled with the temperature in the environment of the skin surface;

detecting a patient skin measured temperature value using said patient skin temperature sensor;

detecting an environment measured temperature value using said environment temperature sensor;

providing an evaluating device for receiving a patient skin measured temperature value and for receiving an environment measured temperature value;

determining a rate of change of said patient skin measured temperature value over time with said evaluating device;

determining a rate of change of said environment measured temperature value over time with said evaluating device;

comparing said rate of change of said patient skin measured temperature with said environment measured temperature;

determining a status of the contact of said patient skin temperature sensor with the skin surface of the patient based on said comparison of said rate of change of said patient skin measured temperature and said rate of change of said environment measured temperature.

15. A temperature-measuring method in accordance with claim 14, wherein said evaluating device calculates a body core temperature from said patient skin measured temperature value and said environment measured temperature value.

16. A temperature-measuring method in accordance with claim 14, wherein said evaluating device forms a sum and a difference from said patient skin measured temperature value and said environment measured temperature value and compares the changes over time in the sum and the difference with respect to similar rates of change of the signals as an indicator of the contact of the patient skin temperature sensor with said skin surface.

17. A temperature-measuring method in accordance with claim 16, wherein said evaluating device determines the the signals of said patient skin temperature sensor and said environment temperature sensor have similar rates of change by forming a Pearson'"'"'s correlation coefficient from the sum and the difference. signal when said patient skin temperature sensor is not in contact with said skin surface.

18. A temperature-measuring method in accordance with claim 16, wherein said patient skin temperature sensor is not in contact with said skin surface when said rate of change of said patient skin temperature sensor is similar to said rate of change of said environment temperature sensor.

19. A temperature-measuring method in accordance with claim 16, wherein said patient skin temperature sensor has a first thermal conductivity and said environment temperature sensor has a second thermal conductivity, said second thermal conductivity being different from said first thermal conductivity.

20. A temperature-measuring method in accordance with claim 16, further comprising an alarm means for providing an alarm signal when said patient skin temperature sensor is not in contact with said skin surface.