After intubation, a sustained end-tidal CO2 waveform over several breaths is the most reliable bedside sign that the tube is in the trachea. Chest rise and auscultation can mislead. During cardiac arrest, a low but present waveform still confirms placement, and a sudden rise in end-tidal CO2 is an early sign of return of circulation. A flat trace means the tube is out until proven otherwise.
- Attach waveform capnography before or immediately after every intubation.
- Look for a consistent waveform over several breaths, not a single reading.
- Treat a flat trace as oesophageal intubation until proven otherwise.
- Keep capnography on during transfer and after any patient move.
Why it matters
Unrecognised oesophageal intubation remains a preventable cause of death.
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