ETCO2 stands for End Tidal carbon dioxide. Which option correctly reflects this?

• A. End Tidal carbon dioxide
• B. End Tracheal carbon dioxide
• C. Exhaled Total carbon dioxide
• D. Emitted Tidal carbon dioxide

Answer: (A)

ETCO2 stands for End-Tidal carbon dioxide, which means the concentration of CO2 measured at the end of an exhaled breath. In capnography, this end point reflects what’s left in the alveoli just before a new breath starts, making it a reliable indicator of ventilation status during sedation. Therefore, the wording that matches is End Tidal carbon dioxide. The other phrases don’t fit clinical terminology: End Tracheal would imply a measurement inside the trachea, Exhaled Total CO2 isn’t the standard term used in capnography, and Emitted Tidal CO2 uses different wording that isn’t correct.