On capnography, what indicates proper placement of an ETT or SGA?

• A. Absence of waveform.
• B. Flat line.
• C. Presence of a continuous alveolar waveform.
• D. Irregular waveform.

Answer: (C)

Capnography verifies airway placement by showing exhaled CO2 in real time. A continuous alveolar waveform with a measurable end-tidal CO2 means CO2 is being exhaled from the lungs, indicating the airway device is in the trachea and ventilation is effective. This alveolar portion of the waveform confirms gas exchange is occurring with the device in the correct place. If the tube were in the esophagus or ventilation wasn’t happening, you’d typically see no CO2 at all (an absent or flat waveform). An irregular waveform might suggest leaks, obstruction, or poor seal, but it doesn’t confirm correct placement the way a continuous alveolar waveform does.