Pre-oxygenation: High flow nasal cannula vs. BVM

A sentinel event is one where, amongst other different outcomes, leads to death. In critical care, anesthesia, and emergency medicine, we often deal with emergent airways on patients who are on the brink of death unless we intervene expediently. Despite having performed many intubations in my young career, I have the utmost respect for every airway. Any one of them can become at catastrophe at any time. If you’re not prepared and thinking two steps ahead, you’re honestly not adequately trained. If you haven’t been burned before, you have not performed sufficient procedures to truly be proficient. You need to know how to preoxygenate your patient and have various tools to use such as your BVM or high flow nasal cannula.

Please don’t take offense by that, it’s just the name of the game. In residency I made sure to hunt down every single airway possible. In med school I hung out with the anesthesiologists to attempt to intubate their patients prior to surgery. Some of the ED attendings during residency had my number and would page/text me to perform the procedure to provide me with more experience. In fellowship I would love to tag along with the anesthesia residents on the “airway team” and go intubate patients throughout the hospital.

A way to mitigate the risk of patient demise is to attempt to pre-oxygenate your patients as much as possible prior to intubation. There are many strategies to do this, a NRB, BVM, NIV, and HFNC which will all deliver 100% FiO2. A regular nasal cannula won’t really cut it on the sick patients. Remember, one needs to be prepared for catastrophe to occur on EVERY AIRWAY. This RCT from 2015 which is completely free compared in 40 pts the strategy of pre-oxygenating the patients with either HFNC of BVM prior to intubation. There were largely no significant differences between the two groups in their outcomes, but they did find one significant difference that really caught my eye. The SpO2 dropped significantly in the one minute of apnea after induction in the group that was preoxygenated with the BVM (p=0.001). Sure, that didn’t change the outcomes overall in these 40 patients which is admittedly a small sample size, but it only takes one airway to become a true disaster where the patient develops anoxic brain injury or even dies during the intubation due to hypoxia. That would be a sentinel event that will keep you up at night. I do not wish that on anyone. Please be careful with your airway out there. The most important skill is knowing how to bag your patient. You should also be trained in how to cut the neck so that when it does happen, and I wish you never have to go through this yourself, you don’t freeze.


Link to Article


Simon M, Wachs C, Braune S, Heer G de, Frings D, Kluge S. High-flow nasal cannula versus bag-valve-mask for preoxygenation before intubation in subjects with hypoxemic respiratory failure. Respiratory Care 2016;61:1160–7.

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