Method For Measuring The Transcutaneous Co2 Partial Pressure On An Ear Lobe

• US 20080064942A1
• Filed: 05/12/2005
• Published: 03/13/2008
• 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
• Granted Patent: US 7,474,908 B2
• Time in Patent Office: Days
• 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 (1) which has a measuring device for measurement of the transcutaneous CO₂ partial pressure and a heating element (8, 15) for warming a sensor contact surface (25) intended for contact with the ear lobe, and during said method the sensor contact surface (25) is heated, characterized in that the sensor contact surface (25) is maintained at an elevated temperature of at least 41.5°

C. during an initial phase to prevent a measurement-related overshoot of the measured value of the transcutaneous CO₂ partial pressure over the transcutaneous CO₂ partial pressure achieved after stabilization, and afterward the temperature of the sensor contact surface (25) is reduced to between 37°

C. and 41°

C.

2. A method according to claim 1, characterized in that the temperature is decreased by at least 1°

C., preferably at least by 2°

C.

3. A method according to claim 1 or 2, characterized in that the elevated temperature is in the range of 41.5°

C. to 44°

C.

4. A method according to claim 1, characterized in that the initial phase with the elevated temperature, during which the sensor contact surface (25) is applied to the earlobe, lasts between 5 and 60 minutes, preferably between 6 and 30 minutes, especially between 6 and 15 minutes.

5. A method according to claim 4, characterized in that the initial phase lasts between 6 and 30 minutes and the elevated temperature is at least 42°

C.

6. A method according to claim 5, characterized in that the elevated temperature is approx. 44°

C. and the initial phase preferably lasts between 6 and 20 minutes.

7. A method according to claim 1, characterized in that the reduction of the temperature of the sensor contact surface (25) occurs at a rate of less than or equal to 1°

C. per 10 seconds, preferably less than or equal to 1°

C./min.

9. A sensor (1) for implementation of the method according to claim 1, which has a measuring device for measuring the transcutaneous CO₂ partial pressure and a heating element (8, 15) for heating a sensor contact surface (25) intended for contact with an earlobe, characterized in that it has a heater control (41) with a timer (42) which reduces the heating power of the heating element (8, 15) after a predefined period, so that the temperature of the sensor contact surface (25) is reduced.

10. A sensor according to claim 9, characterized in that the predefined period after which the heater control (41) reduces the heating power of the heater (8, 15) is adjustable.

8. 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, during which the skin at a measurement site for the transcutaneous CO₂ partial pressure is maintained at an elevated temperature of at least 41.5°

C. during an initial phase and afterward the temperature of the skin is reduced to between 37°

C. and 41°

C.