Journal of applied physiology
-
Comparative Study
Infrared CO2 analyzer error: an effect of background gas (N2 and O2).
Three infrared CO2 analyzers were tested for the effect of background gases: the Ametek CD-3A (Ametek, Thermox Instruments Division, Pittsburgh, PA), the Dräger Multiwarn P CO2 (Dräger, L ubeck, Germany), and the Servomex 1440 (Servomex, Crowborough, East Sussex, UK). Various CO2 concentrations were prepared with Wösthoff precision pumps (H. Wösthoff, Bochum, Germany). ⋯ When the CO2 analyzers were calibrated with N2 as the background gas, the CO2 reading in an O2-enriched atmosphere was 8% lower than the true value. Conversely, calibration with O2 as the background gas resulted in a 10% overestimation of CO2 levels when N2 was the background gas. This error may be important in a few fields of respiratory physiology.