Guide — Airway Management
Endotracheal Intubation
Endotracheal intubation is a team procedure, and the respiratory therapist is at the head of the bed for nearly all of it — preparing and checking the equipment, preoxygenating, handing the tube, confirming placement, and securing the airway. This guide walks the RT through the role, the confirmation that actually proves the tube is in the trachea, and the immediate post-intubation checks.
10 min read · Airway Management
Written by Apex Respiratory Editorial Team
Educational use only. This material supports respiratory therapy education and exam review. It is not medical advice and is not a substitute for clinical judgment, institutional protocols, or physician orders. Always follow facility policies and current provider orders, and verify calculations independently before clinical use.
Overview
Endotracheal intubation places a cuffed tube through the vocal cords into the trachea to secure a definitive airway. The indications come down to a few questions: is the patient failing to oxygenate, failing to ventilate, or failing to protect the airway — for example a depressed mental status — or is the clinical course expected to deteriorate toward one of those failures? Any one of those is a reason to intubate.
For the respiratory therapist, intubation is less about who holds the laryngoscope and more about owning the parts that make it safe: assembling and testing the equipment, preoxygenating well, providing bag-mask ventilation and suction, confirming placement with capnography, securing the tube, and starting ventilation. Most of the preventable harm in intubation — an unrecognized esophageal tube, a desaturation during a prolonged attempt, a tube down the right mainstem — falls squarely in the RT’s lane.
Key Concepts
Tube confirmation is the single most important concept in intubation, and the methods are not interchangeable. Waveform capnography proves the tube is in the trachea; the chest X-ray only tells you how deep it sits.
| Method | What It Tells You |
|---|---|
| Waveform capnography | Sustained EtCO₂ over ~6 breaths — the gold standard for tracheal placement |
| Colorimetric CO₂ detector | Color change from purple to yellow — an acceptable backup to waveform capnography |
| Bilateral breath sounds + absent epigastric sounds | Supports tracheal placement; gurgling over the epigastrium suggests the esophagus |
| Symmetric chest rise | Equal expansion supports correct placement; unilateral rise suggests a mainstem tube |
| Tube misting | Condensation in the tube on exhalation is a soft, supporting sign only |
| Chest X-ray | Confirms depth (tip 3–5 cm above the carina) — not tracheal versus esophageal placement |
- Tube sizing. An adult woman usually takes a 7.0–8.0 mm internal-diameter tube (often 7.5), and an adult man a 7.5–8.5 (often 8.0). Larger tubes lower airway resistance and ease bronchoscopy but are harder to pass; the size is chosen for the airway, not the convenience.
- Depth and tip position. As a starting point, secure at about 21 cm at the lips in women and about 23 cm in men, aiming for a tip 3 to 5 cm above the carina. That window keeps the cuff clear of the cords while staying out of a mainstem bronchus.
- Cuff inflation. Inflate the cuff to the minimal occlusive volume and confirm a cuff pressure of 20 to 30 cmH₂O. Too little leaks and risks aspiration; too much compresses tracheal mucosa and risks ischemic injury.
Assessment & Findings
- Esophageal intubation. No CO₂ waveform on capnography, gurgling heard over the epigastrium with ventilation, no chest rise, and worsening hypoxemia. A missing waveform is treated as a misplaced tube until proven otherwise.
- Right mainstem intubation. Unilateral — usually right-sided — breath sounds with diminished or absent sounds on the left. Withdraw the tube slightly until breath sounds are bilateral, then reconfirm depth.
- Adequate placement. A sustained capnography waveform, bilateral breath sounds, absent epigastric sounds, and symmetric chest rise together support a correctly placed tube, pending the confirmatory film.
- Oxygenation during the attempt. Watch the SpO₂ throughout. A falling saturation is the cue to stop, reoxygenate with bag-mask ventilation, and only then reattempt.
RT Priorities / Interventions
The procedure follows a predictable sequence, and the RT has a defined job at each step.
- Position and assemble. Position the patient in the sniffing position — ear to sternal notch — and assemble and check every piece of equipment before the attempt: laryngoscope and light, the planned tube plus a backup size, stylet, suction, bag-valve-mask, and capnography.
- Preoxygenate (denitrogenate). Deliver 100% O₂ for 3 to 5 minutes, or have the patient take 8 vital-capacity breaths, to wash out nitrogen and build an oxygen reserve that buys apneic time during the attempt.
- Support the laryngoscopy. Provide bag-mask ventilation and suction, hand the tube as the cords are visualized, and apply external laryngeal manipulation (BURP) if the intubator asks for it to improve the view.
- Pass, inflate, and confirm. Once the tube is through the cords, inflate the cuff to the minimal occlusive volume (cuff pressure 20–30 cmH₂O) and confirm placement with waveform capnography before anything else.
- Secure, ventilate, and film. Secure the tube at the correct depth, begin ventilation, and obtain the post-intubation chest X-ray to confirm the tip sits 3 to 5 cm above the carina. Use the ideal body weight calculator to set the initial tidal volume on predicted body weight once the airway is established.
Common Pitfalls
- Relying on auscultation alone. Breath sounds can mislead, especially in a noisy resuscitation. Waveform capnography is the gold standard and must be the confirmation, not an afterthought.
- Unrecognized esophageal intubation. The most lethal error. A missing CO₂ waveform means the tube is presumed esophageal and removed — do not talk yourself out of a flat capnograph.
- Right mainstem intubation. Advancing the tube too far drops it into the right mainstem. Unilateral breath sounds call for withdrawing the tube slightly and reconfirming.
- Inadequate preoxygenation. Skipping or shortcutting denitrogenation leaves no oxygen reserve, so the patient desaturates almost as soon as the attempt begins.
- A prolonged attempt without reoxygenating. Pushing on through a falling SpO₂ courts hypoxic injury. Stop, bag-mask ventilate back to a safe saturation, and reattempt.
- Over-inflating the cuff. Inflating past the minimal occlusive volume drives cuff pressure above 30 cmH₂O and risks tracheal mucosal injury.
Board Exam Pearls
- Waveform capnography confirms tracheal placement — if a stem offers it as the answer for confirming the tube, take it.
- Starting depth is 21 cm at the lips in women and 23 cm in men, with the tip 3 to 5 cm above the carina.
- Right mainstem intubation is the most common malposition — unilateral right-sided breath sounds, fixed by withdrawing the tube slightly.
- Cuff pressure runs 20 to 30 cmH₂O, set to the minimal occlusive volume.
- Preoxygenate before every attempt — denitrogenation is what buys the apneic time.
FAQ
What is the gold standard for confirming endotracheal tube placement?
Waveform capnography is the gold standard for confirming tracheal placement. A sustained end-tidal CO₂ waveform over roughly six breaths confirms the tube is in the trachea, because a tube in the esophagus will not produce a persistent CO₂ tracing. A colorimetric CO₂ detector that turns from purple to yellow is an acceptable backup, and bilateral breath sounds, absent epigastric sounds, symmetric chest rise, and tube misting are supporting signs. The chest X-ray confirms depth, not whether the tube is tracheal or esophageal.
How deep should an ETT sit at the lips?
As a starting rule, the tube sits at about 21 cm at the lips in an average adult woman and about 23 cm in an average adult man. The goal is a tip 3 to 5 cm above the carina, which keeps the cuff below the cords while avoiding a mainstem bronchus. Depth is then confirmed on the post-intubation chest X-ray and adjusted as needed.
What are the signs of an esophageal intubation?
The decisive sign is the absence of a sustained CO₂ waveform on capnography. Other findings include gurgling heard over the epigastrium with ventilation, no visible chest rise, and progressive hypoxemia. An unrecognized esophageal intubation is rapidly fatal, so a missing capnography tracing means the tube is presumed misplaced and removed.
Which mainstem bronchus does a tube usually enter if advanced too far?
If the tube is advanced too far it usually enters the right mainstem bronchus, because the right mainstem branches at a less acute angle than the left. The clue is unilateral — usually right-sided — breath sounds with diminished or absent sounds on the left. The fix is to withdraw the tube slightly until breath sounds are bilateral, then confirm depth on the chest film.
Put it to work
Once the tube is in and confirmed, the next move is ventilation. Run the patient’s height through the calculator to set an initial tidal volume on predicted body weight rather than actual weight.
Open the IBW Calculator →Related Resources
Sources
- Kacmarek RM, Stoller JK, Heuer AJ. Egan's Fundamentals of Respiratory Care. 12th ed. Elsevier; 2021. Airway management chapter.
- Apfelbaum JL, Hagberg CA, Connis RT, et al. 2022 American Society of Anesthesiologists practice guidelines for management of the difficult airway. Anesthesiology. 2022;136(1):31-81.