Apneic oxygenation

Overview

Apneic oxygenation is a technique that prolongs "safe apnea time" (time until desaturation to SaO2=88-90%) after induction of apnea. This increases time for laryngoscopy/intubation.

  • an adjunct to preoxygenation: used to prolong oxygenation after optimal preoxygenation
  • low cost in terms of resources and set-up

Physiology

  • gas exchange during apnea creates subatmopsheric pressure in the alveoli
    • in healthy lungs, 200-250mL O2 per minute can be drawn into blood stream
    • in the absence of ventilation (i.e. during apnea), only 10-20mL CO2 enters alveoli from bloodstream per minute, due to increased CO2 tension
    • this causes a net decrease in gas in the alveoli
  • this gradient can draw air into the lungs, even absent diaphragmatic movement
  • increases safe apnea time in healthy volunteers from 1 minute (room air) to 8-9 minutes

Indications

  • intubation

Contraindications

  • severe maxillofacial trauma
  • obstructed nares

Equipment Needed

  • nasal cannula
  • second oxygen source, e.g. mobile O2 tank

Procedure

  1. Start pre-oxygenation while sitting upright, only lay back once RSI drugs pushed.
  2. During preoxygenation, keep the nasal cannula on underneath your primary preoxygenation technique.
    • This can be achieved whether you use a mask, NPPV, or BVM; a good seal can still be obtained. Alternatively, you can use the high flow nasal cannula technique for preoxygenation.
    • Normal adjunctive airway techniques/equipment (jaw thrust, oropharyngeal airway) remain useful. In particular, nasal trumpet can maintain patencny of at least one nare.
  3. Attach the nasal cannula to a separate oxygen source at 15L.
  4. After preoxygenation, leave the nasal cannula on after removing mask/NPPV/BVM. It should not get in the way of laryngoscopy.
    • Consider taping cannula to face to prevent dislodgement.

Complications/Limitations

  • complications are limited and most can be quickly remedied by removing nasal cannula
    • if not well-positioned/attached, may complicate laryngoscopy
    • high flow oxygen from nasal cannula is cold and dry; may not be well-tolerated by patient
    • extremely high flow oxygen (>70 L/M) may cause barotrauma
    • increased apnea time increases respiratory acidosis
  • not shown to improve saturation in critically ill patients

See Also

Airway Pages

External Links

https://emcrit.org/pulmcrit/preoxygenation-apneic-oxygenation-using-a-nasal-cannula/

References

  • Moran C, Karalapillai D, Darvall J, Nanuan A. Is it time for apnoeic oxygenation during endotracheal intubation in critically ill patients? Critical care and resuscitation. 16(3):233-5. 2014.
  • Semler MW, Janz DR, Lentz RJ. Randomized Trial of Apneic Oxygenation during Endotracheal Intubation of the Critically Ill. American journal of respiratory and critical care medicine. 2015.
  • Hayes-Bradley C, Lewis A, Burns B, Miller M. Efficacy of Nasal Cannula Oxygen as a Preoxygenation Adjunct in Emergency Airway Management. Annals of emergency medicine. 68(2):174-80. 2016.
  • Lynn E. Teller, M.D., Christian M. Alexander, M.D., M. Jack Frumin, M.D., Jeffrey B. Gross, M.D.; Pharyngeal Insufflation of Oxygen Prevents Arterial Desaturation during Apnea. Anesthes 1988;69(6):980-982.