Which method provides the most reliable immediate confirmation of endotracheal tube placement?

• A. Chest rise with equal bilateral breath sounds
• B. Absence of epigastric sounds
• C. Positive end-tidal CO2 detection
• D. Lung ultrasound confirmation

Answer: (C)

The key idea is that real-time capnography provides immediate, objective proof that the tube is in the trachea and the lungs are being ventilated. When the endotracheal tube is correctly positioned, exhaled CO2 appears, producing a consistent waveform and a measurable end-tidal CO2 value right away. This makes capnography the fastest and most reliable way to confirm placement in the moment after intubation.

Other signs like chest rise with bilateral breath sounds can be misleading—air may move into the stomach or a bag-valve device can produce chest movement even if the tube isn’t in the trachea. Absence of epigastric sounds helps screen for esophageal intubation but isn’t definitive. Lung ultrasound can confirm placement, but it requires specific skills and equipment and isn’t as immediately accessible in all settings.