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What is nasal high flow (NHF) therapy?  [7 key facts]   


Firstly, it’s called many things, High flow nasal cannula (HFNC), high flow therapy (HFT), high flow oxygen / therapy (HFO/T), nasal high flow (NHF), or just plain high flow (HF).

Our preferred generic descriptor is nasal high flow (NHF) because it’s all about Nasal delivery of High Flows of humidified air.

Commercially, we call it Optiflow™, which can be delivered in several different ways.


It can deliver high levels of oxygen, but it is significantly more sophisticated than that – the higher rates of flow (independent of oxygen) confer benefits that oxygen alone cannot, i.e., reduction of dead space and dynamic, positive airway pressure, both of which are capable of increasing alveolar ventilation.

Mucociliary transport system


The high flow rates, greater than those seen with conventional oxygen delivery devices (and more than peak inspiratory airflow), are tolerable because the air is heated and humidified.

Watch the effect of low humidity on the right, turn audio on. 


It is a form of noninvasive respiratory therapy, but it is not a ventilator nor is it a CPAP device.


It is designed to treat spontaneously breathing people experiencing respiratory compromise. 

-    High respiratory rate
-    Dyspnea
-    High work of breathing
-    Low SpO2
-    High PaCO2

How quickly does NHF work? 


It has been proven in an ever-growing number of RCTs to be superior to conventional oxygen therapy (COT) and non-inferior (in some studies) to noninvasive therapy (NIV). 

Data from hundreds of controlled trials have now been consolidated into clinical practice guidelines and recommendations.


What sets NHF apart from COT devices and bi-level NIV is that it is delivered via a nasal cannula (sometimes a tracheotomy).

This means a mask seal is not required, making setup a simpler process. 

This results in several benefits to patients, including facilitating better communication with caregivers and loved ones.