How should you verify the tube depth after intubation?

• A. Trust initial depth without rechecking
• B. Only recheck depth with X-ray
• C. Confirm depth with capnography and auscultation; check tube markings at the teeth
• D. Depth is not important if breath sounds are present

Answer: (C)

Verifying endotracheal tube depth after intubation hinges on using multiple bedside checks to confirm both placement in the trachea and an appropriate depth. Capnography provides immediate physiological confirmation by showing a consistent exhaled CO2 waveform and a measurable end-tidal CO2, which strongly indicates the tube is in the trachea. Auscultation over both lungs helps ensure bilateral ventilation and helps detect problems like mainstem intubation or esophageal intubation if breath sounds are absent or markedly unequal. Checking the tube markings at the teeth or lips gives a concrete depth reference so you can detect any movement and prevent the tube from being too shallow or too deep.

These checks work together because no single sign is perfect on its own. Relying only on initial depth or only on chest sounds can miss tube migration or misplacement, and waiting for imaging alone (like an X-ray) can delay confirmation in urgent settings. Imaging can later verify position, but capnography, auscultation, and depth markings provide rapid, at-a-glance verification right at the bedside.