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Updated: Sep 29, 2026
Evaluation of Capnography Sampling Line Compatibility and Accuracy when Used with a Portable Capnography Monitor
Published on: September 29, 2020
Noninvasive carbon dioxide monitoring during neurosurgical procedures in adults: end-tidal versus transcutaneous
D Scott McBride1, Joel O Johnson, Joseph D Tobias
1Department of Child Health, University of Missouri, Columbia 65212, USA.
Background:
We prospectively compared transcutaneous (TC) versus end-tidal (ET) carbon dioxide monitoring during neurosurgical procedures in adults.
Methods:
After calibration and an equilibration time for the TC-CO2 monitor, arterial blood gas (ABG) values were obtained as clinically indicated. The PaCO2 values were compared with the values recorded by the noninvasive monitors (TC and ET).
Results:
The ET-CO2 to PaCO2 difference was 6.1 +/- 5.6 mm Hg, and the TC-CO2 to PaCO2 difference was 3.7 +/- 2.9 mm Hg. The difference between the PaCO2 and ET-CO2 was 3 mm Hg or less in 17 of 57 values, while the difference between the PaCO2 and TC-CO2 was 3 mm Hg or less in 35 of 57 values. Linear regression analysis of ET-CO2 versus PaCO2 revealed a slope of 0.381 +/- 0.007. Linear regression analysis of TC-CO2 versus PaCO2 revealed a slope of 1.17 +/- 0.008.
Conclusion:
Transcutaneous CO2 monitoring provides a more accurate estimate of PaCO2 than ET-CO2 monitoring during neurosurgical procedures.
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