What does capnography indicate after airway placement?

What does capnography indicate after airway placement?

• A. It indicates intrathoracic ventilation and tube position, and shows ventilation trends
• B. It measures arterial oxygen tension
• C. It records heart rhythm
• D. It indicates nutritional status

Answer: (B)

Capnography measures end-tidal CO2 in the exhaled gas, shown as a waveform with a numeric end-tidal CO2 value. After placing an airway, it serves two key roles: it confirms the tube is in the trachea by showing a CO2 waveform, and it lets you monitor ventilation over time. If CO2 is present and a normal waveform appears, you’re ventilating intrathoracically. Tracking ETCO2 also reveals trends: rising or falling values reflect changes in ventilation or perfusion, while a sudden drop or loss of waveform can signal disconnection, apnea, or tube issues. Capnography does not measure arterial oxygen tension (that’s from ABG or SpO2), it does not record heart rhythm, and it does not indicate nutritional status.

Capnography measures end-tidal CO2 in the exhaled gas, shown as a waveform with a numeric end-tidal CO2 value. After placing an airway, it serves two key roles: it confirms the tube is in the trachea by showing a CO2 waveform, and it lets you monitor ventilation over time. If CO2 is present and a normal waveform appears, you’re ventilating intrathoracically. Tracking ETCO2 also reveals trends: rising or falling values reflect changes in ventilation or perfusion, while a sudden drop or loss of waveform can signal disconnection, apnea, or tube issues. Capnography does not measure arterial oxygen tension (that’s from ABG or SpO2), it does not record heart rhythm, and it does not indicate nutritional status.