MIA 2012: Weingart SD, Levitan RM. Preoxygenation and prevention of desaturation during emergency airway management. Ann Emerg Med. 2012 Mar;59(3):165-75.e1.

Bottom Line ¹

Why It’s Important for Emergency Medicine

• Emergent airway management is a staple to our practice – it’s what we get paid for.  This article is a systematic breakdown of preoxygenation and perioxygenation techniques to minimize the risk of hypoxia.
• The techniques to maximizing safe apnea are simply summarized and, more importantly, easily reproducible across all emergency medicine departments.  You have no excuse not to practice these…

Major Points

1. Most non-rebreather masks (NRM) deliver an FiO2 of 60-70%.  You can get to 90% FiO2 by turning the O2 flow beyond the 15L/min marking.  Crank it up to 30-60L/min.
2. If possible, have patients breathe normally for 3 minutes (tidal volume breaths), or take 8 maximal breaths (vital-capacity breaths) at the high FiO2.
3. For patients with an SaO2 of 93-95% despite Step 2, try increasing airway pressure with BiPap, CPAP, or PEEP valves on a bag-valve mask (BVM) .
4. Preoxygenate in the sitting position (or reverse-trendelenberg).  Laying down causes more atelectasis.
5. Safe apnea time (time it takes to drop down to 88% SaO2) is unpredictable.  In a perfectly preoxygenated, denitrogenated healthy patient, it can be as long as 8 minutes.  In an obese, critically-ill patient, you might have around 23 seconds…
6. Nasal Oxygenation During Efforts Securing A Tube (NO DESAT) – Enhance apneic oxygenation by leaving a NC on @ 15L/min during intubation.
7. If the SaO2 < 90%, ventilate with a BVM, but do it with LOW pressure, LOW volume, and LOW rate.
8. Once paralyzed, maximize airway patency by slightly lifting the head of the bed or pad beneath the head and shoulder, placing face parallel to ceiling, and aligning the external auditory meatus with the sternal notch.
9. In high risk patients, rocuronium gives you longer safe apnea time compared to succinylcholine.

Criticisms

The majority of the articles reviewed were based on anesthesiology and critical care literature; not many studies were conducted in emergency medicine settings.

Reviewed by M. Washington

MIA 2012 = Most Interesting Articles series of 2012

Author information

Michelle Lin, MD

ALiEM Founder and CEO
Professor and Digital Innovation Lab Director
Department of Emergency Medicine
University of California, San Francisco

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