End-tidal CO2 excretion waveform and error with gas sampling line leak
When there is a loose connection between an end-tidal CO2 sampling line and the CO2 analyzer (Saracap), the CO2 excretion waveform is very unusual and consists of a long plateau followed by a brief peak, rather than the usual square CO2 excretion waveform. The long CO2 plateau is caused by entrainment of room air through the leaky connection by the continuous CO2 analyzer suction, and the brief CO2 peak is caused by the next PIP, which transiently pushed undiluted end-tidal gas through the sampling line into the CO2 analyzer. Because the O2 and N2O values digitally displayed by the Saracap are mean exhalation values, the O2 and N2O concentrations are a function of both size of the leak and the PIP.