Mainstem Intubation Recognition
Objective: Catch a right-mainstem tube after every move — depth at the teeth, bilateral rise, and EtCO₂ that does not excuse a silent left lung.
Why This Is Hard
You had a waveform and a sat of 94%. After the move to the stretcher the left chest is quiet. Crews push PEEP and blame the patient. AHA confirmation teaching: waveform tells you the tube is in the airway tree, not that it is equally in both lungs.
- Note centimeter depth at the teeth or gums when you confirm, and after every major move.
- Look at both chests. Auscultate both axillae. The stomach still gets a listen.
- EtCO₂ present plus a silent left chest is mainstem or pneumothorax — not “good enough.”
Field Rules (Education)
- Clues: unilateral chest rise, high bag resistance, sat falling, breath sounds on one side.
- Fix: deflate the cuff if needed, pull back 1–2 cm at a time to a typical adult depth per your training, re-inflate, reconfirm waveform and bilateral rise.
- DOPE: Displacement includes mainstem. See DOPE-S.
- Kids: mainstem happens fast because the trachea is short. Recheck after every bump.
Field Pitfalls
- Calling the tube good because EtCO₂ is 35 with a silent left chest.
- Never writing a depth, then guessing in the truck.
- Pushing the tube deeper “to make sure it stays.”
Practice
60-second drill
Partner: adult ETT at 26 cm, left chest silent after a move, waveform present. First two actions.
Related: Post-intubation, Capnography.
Sources & Further Study
Named guidelines for further study. They are not clinical orders and do not replace your protocol or medical direction.
- NASEMSO National Model EMS Clinical Guidelines (2022) — U.S. EMS model language; protocol still wins
- AHA 2025 Part 7: Adult BLS — waveform capnography confirms airway placement — physical exam still catches mainstem
- AHA/AAP 2025 PALS — DOPE includes displacement / mainstem in children
Education only. Apply learning within your protocols and medical direction. This is not clinical care guidance.
Check Your Understanding
Street decisions from this lesson only. After you check, the key is highlighted. Education practice — not a certification exam.