A Comparison Of Transcutaneous And End-Tidal Carbon Dioxide Monitoring Among Three Devices Providing Supplemental Oxygen To Volunteers

Purpose: The aim of this study was to compare the accuracy of TC-CO2 measurement and PETCO2 measurement using three devices: two types of nasal cannulas (nasal cannula, nasal prong) and one nasal mask (modified nasal mask), and to assess which device is the most useful. Measurements: The capnometer measured the PETCO2 in expired gas from the nasal cavity via each of the three devices attached to the nostril or nose. Volunteers received supplemental O2 through each device at flow rates of 1, 2, 3, 4, 6, 8 and 10 L/min for 2 minutes each. The accuracy of the three devices was compared. Main Results: The accuracy was greater for all three devices with increases in supplied O2. With the nasal cannula, the mean accuracy increased from 1.2±0.6 to 6.5±3.0. With the modified nasal mask, the mean accuracy increased from 1.8±0.6 to 7.1±1.4. And with the NP, the mean accuracy increased from 3.4±0.4 to 7.5±0.7. Conclusions: The accuracy trends to increase with increasing supplemental O2 among three devices and when used at O2 flow rates of 1, 2 or 3 L/min, any of the three devices can provide good qualitative information. Within O2 flow rates of 1-4 L/min, the most useful device is nasal cannula may be assessed since the accuracy is smallest in three devices.