Which method is essential to confirm endotracheal tube placement after insertion?

• A. End-tidal CO2 monitoring
• B. Chest radiograph
• C. Auscultation alone
• D. Pulse oximetry alone

Answer: (A)

End-tidal CO2 monitoring provides real-time, objective confirmation that the tube is in the trachea. When the tube is correctly placed, exhaled CO2 is detected with a characteristic waveform and a detectable PETCO2 value, confirming ventilation through the lungs. If the tube is in the esophagus, little or no CO2 is detected and the waveform is absent, signaling misplacement promptly. This immediate feedback is far more reliable than listening with a stethoscope or waiting for a chest X-ray, which takes time and may not reflect current placement. Pulse oximetry shows oxygenation, not tube position, and can be misleading in the moment if perfusion is poor.