Airway management

Preoxygenation and apnoeic oxygenation

Reviewed Nov 2026·5 references
New· views rounded down, updated weekly

Preoxygenate for 3-5 min to an ETO2 ≥ 85-90%; use NIV in hypoxaemic patients (PREOXI), keep nasal oxygen during apnoea, and give gentle bag-mask ventilation between induction and laryngoscopy (PreVent).

At the bedside

Timed steps
  1. 1

    Preoxygenate

    3-5 min

    Head up 20-30°. Tight-fitting face mask with 15 L/min (or BVM with PEEP valve), or NIV (PEEP 5-8, pressure support 5-10, FiO2 1.0) in hypoxaemic patients; HFNC 60 L/min is an alternative. Target ETO2 ≥ 85-90% if measurable.

  2. 2

    Apnoeic oxygenation

    During apnoea

    Nasal cannula 10-15 L/min (or HFNC) left on throughout laryngoscopy.

  3. 3

    Bag-mask ventilation

    Induction to laryngoscopy

    Gentle BMV (low pressure, 10/min) with PEEP after induction reduces severe hypoxaemia.

  4. 4

    Stop at threshold

    Attempt

    Abort the attempt if SpO2 falls to ~93% (or earlier in shunt); re-oxygenate with BMV or SGA before the next attempt.

Red flag · call your senior now
SpO2 < 93% despite NIV preoxygenation: shunt physiology, expect rapid desaturation.
Red flag
Cannot preoxygenate (agitation): consider delayed sequence intubation with ketamine 1 mg/kg.
Pitfall
Loose-fitting non-rebreather mask (FiO2 often < 0.7).
Pitfall
Removing NIV or HFNC to 'get ready' minutes before induction.
Pearl
Delayed sequence intubation: ketamine (0.5-1 mg/kg) dissociation allows effective NIV preoxygenation in an agitated patient.

References

  1. 1

    Gibbs KW, Semler MW, Driver BE, et al. Noninvasive ventilation for preoxygenation during emergency intubation (PREOXI). N Engl J Med. 2024;390(23):2165-2177

  2. 2

    Casey JD, Janz DR, Russell DW, et al. Bag-mask ventilation during tracheal intubation of critically ill adults (PreVent). N Engl J Med. 2019;380(9):811-821

  3. 3

    Higgs A, McGrath BA, Goddard C, et al. Guidelines for the management of tracheal intubation in critically ill adults. Br J Anaesth. 2018;120(2):323-352

  4. 4

    Myatra SN, Shah AP, Ramkumar V, et al. All India Difficult Airway Association 2025 guidelines for the management of unanticipated difficult airway in adults under general anaesthesia. Indian J Anaesth. 2025;69(11):1117-1141

  5. 5

    Acquisto NM, Mosier JM, Bittner EA, et al. Society of Critical Care Medicine clinical practice guidelines for rapid sequence intubation in the critically ill adult patient. Crit Care Med. 2023;51(10):1411-1430

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