High-flow Nasal Cannula: What is it?

High-flow nasal cannula oxygen therapy in adults

Some of you have asked what I mean every time I post something regarding high flow nasal cannula. Let’s start by defining the flow in the different oxygen devices. Regular nasal cannula provides between 1-6 liters of flow. A simple face mask can get you flows between 6-10L/min. Venti masks, aka Venturi masks can get you flow rates between 4-8L/min. The best you can potentially do with a non-high flow device is the non-rebreather which can generate a flow rate of 10-15L/min. Just so we are all clear, every time I see a patient on a non-rebreather my senses step up to the next level. To me, that thing strapped on a patients face means that a decision needs to be made stat as the person who placed it on their face needs a second opinion. It’s time to either place the patient on HFNC, BiPAP, intubate, or my favorite, they just panicked and didn’t know what to do. It happens.

I like the image in particular because it is not signaling any machine in particular. There are a number of different companies who make these devices and I do not know the nitty gritty as to what differentiates them. I just know I love the technology. Would you all like for me to make a YouTube video where I break down the mechanisms of action of the device?

This article is a good review for the time, published in 2015, with the data that existed at the moment. The author reviews the physiologic effects, discusses the dead space washout, the PEEP effect, the benefits of heat and humidification. In addition, they discuss clinical uses such as both hypoxemic and hypercapnic respiratory failure, pre-intubation, post-extubation, sleep apnea, heart failure, and others.

It’s definitely worth a quick read.


Nishimura, M. (2015). High-flow nasal cannula oxygen therapy in adults. Journal of Intensive Care, 3(1).

Link to Abstract

Link to full FREE PDF

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