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How does nasal high flow compare to conventional oxygen therapy?

Conventional oxygen therapy via a low-flow cannula and most styles of oxygen face mask are limited to lower flow rates (up to 10 L/min) in part because the gas is cold and dry making tolerability a significant issue.
 These lower flow rates also limit FiO2 delivery and accuracy and aren’t high enough to offer the benefits of dead-space washout and positive airway pressure.

Although an NHF device can deliver high levels of oxygen (up to 100% FiO2) it’s not specifically an oxygen delivery device. In fact, NHF can be, and is, often used without supplemental oxygen, i.e., with room air – 0.21 FiO2.

Typically, “high flow” refers to flow rates above 15 L/min of a fully humidified air and oxygen mix. These higher flow rates enable mechanisms that cold, dry oxygen alone cannot provide.

See the table below for a comparison of standard COT devices and NHF.


Optiflow Nasal High Flow compared with traditional oxygen delivery systems

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