Preoxygenation & Apneic Oxygenation
Objective: Fill the tank before you take away the patient’s breaths. Positioning, high-flow oxygen, and a nasal cannula during the attempt buy time — they do not replace a backup plan.
Why This Is Hard
Street intubation culture used to be “pull the NRB, take a look.” Desaturation clocks start the moment ventilation stops. Obese, pregnant, pediatric, septic, and already-hypoxic patients desaturate in seconds. The medic who preoxygenates well has time to be careful. The medic who does not gets a crash airway they created.
- Ear-to-sternal-notch / ramp when anatomy allows
- High FiO₂ with a real seal (not a floating NRB)
- Apneic O₂ adjunct on if authorized — still not a backup airway
- Falling SpO₂ → stop, re-oxygenate, change the plan
Fill the Tank
- Position: ear-to-sternal-notch / ramp when anatomy allows. Flat and flexed is a desaturation plan.
- Open and oxygenate: well-fitting NRB at flush rate, or a tight BVM with PEEP if they need assisted breaths — per training/device. Nasal cannula underneath at high flow is a common apneic-oxygenation teaching setup when authorized.
- Time: if the patient is breathing, give them time on high FiO₂ before the first look (protocol windows vary). If they are apneic, you are already behind — two-person BVM first.
- Waveform capnography staged so the first ventilated breath after the tube is confirmed, not guessed.
During the Attempt
- Leave apneic oxygenation on if that is your system’s method. It extends safe apnea time; it does not replace ventilation if they crash.
- Limit look time. If SpO₂ is falling, stop, re-oxygenate with two-person BVM, then try a different plan (see difficult airway and DOPE-S).
- This lesson does not teach RSI drug doses. Drugs without preoxygenation are how people code at induction.
Field Pitfalls
- First look with no suction, no backup, and a flat head.
- Multiple attempts without re-oxygenating.
- Calling preoxygenation “done” because the NRB was near the face with a huge leak.
Practice
60-second drill
Speak a 15-second preoxygenation script: position, flush-rate device or tight BVM, nasal cannula if authorized, suction, backup airway, EtCO₂ staged. Then partner says “SpO₂ dropping mid-look” — you must stop, re-bag two-person, and name one change (blade, position, SGA) before a second look.
Related: Difficult airway, Effective BVM.
Sources & Further Study
Named guidelines for further study. They are not clinical orders and do not replace your protocol or medical direction.
- Difficult Airway Society guidelines
- ASA 2022 Practice Guidelines for Management of the Difficult Airway
- Preoxygenate, position (ear-to-sternal-notch / ramp), and re-oxygenate between attempts. Apneic oxygenation is an adjunct, not a substitute for ventilation or a failed-airway plan.
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.