Method for measuring the transcutaneous CO2 partial pressure on an ear lobe

• US 7,474,908 B2
• Filed: 05/12/2005
• Issued: 01/06/2009
• Est. Priority Date: 05/18/2004
• Status: Active Grant

• Current Assignee: Radiometer Basel AG (Danaher Corporation)
• Original Assignee: Radiometer Basel AG (Danaher Corporation)
• Inventors: Liechty, Dominik, Kagawa, Sohei, Gisiger, Pierre-Alain, Eberhard, Patrick
• Primary Examiner(s): Marmor, II; Charles A
• Assistant Examiner(s): SAIDI, AZADEH
• Application Number:
  US11/596,873
• Publication Number:
  US 20080064942A1
• Time in Patent Office: 1,335 Days
• Field of Search: 700/300, 600/326, 600/323, 600353-354, 600358-359
• US Class Current: 600/354
• CPC Class Codes: A61B 5/14539 for measuring pH
• CPC Class Codes: A61B 5/14542 for measuring blood gases A61B5/14551 takes precedence
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/1477 non-invasive
• CPC Class Codes: A61B 5/1491 Heated applicators

Abstract

In a process for measuring partial transcutaneous CO₂ pressure on an earlobe by means of a sensor having a measuring device for measuring the partial transcutaneous CO₂ pressure and a heating system for heating a sensor contact surface for contact with the earlobe, the sensor contact surface is heated. During a first phase, the sensor contact surface is kept at an elevated temperature of at least 41.5° C. in order to prevent the measured value of partial transcutaneous CO₂ pressure from exceeding, due to the measurement process itself, the partial transcutaneous CO₂ pressure achieved after stabilization. The temperature of the sensor contact surface is then reduced to between 37° C. and 41° C. This facilitates considerably faster evaluation of the measured values.

Claims

1. A method for measurement of the transcutaneous CO₂ partial pressure on an ear lobe by means of a sensor which has a measuring device for measurement of the transcutaneous CO₂ partial pressure and a heating element for warming a sensor contact surface intended for contact with the ear lobe, said method comprising:

maintaining the sensor contact surface at an elevated temperature of at least 41.5°

C. during an initial phase; and

subsequently reducing the temperature of the sensor contact surface by a temperature reduction rate to between 37°

C. and 41°

C.,

wherein the temperature reduction rate is less than or equal to 6°

C. per minute.

2. The method according to claim 1, wherein the temperature reduction rate is less than or equal to 3°

C. per minute.

3. The method according to claim 1, wherein the temperature reduction rate is less than or equal to 1°

C. per minute.

4. A method according to claim 1, wherein the temperature is reduced by at least 1°

C.

5. The method according to claim 1, wherein the elevated temperature is in the range of 41.5°

C. to 44°

C.

6. The method according to claim 1, wherein the initial phase lasts between 6 and 30 minutes.

7. The method according to claim 6, wherein the elevated temperature is at least 42°

C.

8. The method according to claim 7, wherein the initial phase lasts between 6 and 20 minutes and wherein the elevated temperature is approximately 44°

C.

9. A sensor for implementation of the method according to claim 1, comprising:

a measuring device for measuring the transcutaneous CO₂ partial pressure and a heating element for heating of a sensor contact surface intended for contact with an earlobe,

wherein the sensor comprises a heater control with a timer which reduces the heating power of the heating element after a predefined period, so that the temperature of the sensor contact surface is reduced.

10. The sensor according to claim 9, wherein the predefined period is adjustable.

11. A method for prevention an increase of the transcutaneous CO₂ partial pressure in the skin of an earlobe over the CO₂ partial pressure achieved after stabilization during the arterialization of the skin with the measurement of the transcutaneous CO₂ partial pressure, said method comprising:

maintaining the skin at a measurement site for the transcutaneous CO₂ partial pressure at an elevated temperature of at least 41.5°

C. during an initial phase and

subsequently reducing the temperature of the skin by a temperature reduction rate to between 37°

C. and 41°

C.

wherein the temperature reduction rate is less than or equal to 6°

C. per minute.

12. The method according to claim 11, wherein the temperature reduction rate is less than or equal to 3°

C. per minute.

13. The method according to claim 11, wherein the temperature reduction rate is less than or equal to 1°

C. per minute.