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Updated: Aug 7, 2026

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Expired CO2 Measurement in Intubated or Spontaneously Breathing Patients from the Emergency Department
Published on: January 29, 2011
Transcutaneous analysis of arterial PCO2
Summary
Commercially available skin surface PCO2 sensors accurately measure arterial PCO2. Proper calibration methods, including temperature correction and zero offset, are crucial for reliable, noninvasive cardiorespiratory monitoring.
Area of Science:
- Biomedical Engineering
- Respiratory Physiology
Background:
- Skin surface PCO2 sensors offer noninvasive monitoring of arterial PCO2.
- Previous studies reported controversy regarding sensor accuracy due to inappropriate data analysis.
Purpose of the Study:
- To clarify the accurate relationship between skin surface PCO2 and arterial PCO2.
- To establish proper calibration and data analysis methods for skin PCO2 sensors.
Main Methods:
- Sensors were calibrated using a temperature correction factor (4.5%/°C) and a zero offset (-4 torr).
- Accuracy was assessed by calculating the mean and standard deviation of the skin surface to arterial PCO2 ratio.
- Correlation tests involved wide variations in PCO2 within subjects.
Main Results:
- Properly maintained and calibrated sensors accurately report arterial PCO2 (+/- 3 torr) across various clinical conditions.
- Corrected sensor values demonstrate a reliable correlation with arterial PCO2.
Conclusions:
- Skin surface PCO2 monitors provide continuous, noninvasive cardiorespiratory data.
- Accurate calibration and mathematical treatment are essential for validating skin PCO2 sensor performance.
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