Nasal High Flow Therapy


Last Updated: Thursday, 9 April 2020, 6:37PM (NZDT)


Nasal High Flow (aka HFNC, HFNO) has been used by clinicians as respiratory support for COVID-19 patients following the outbreak in China.3, 4, 5
Nasal High Flow is recognized by the World Health Organization (WHO) for treatment of patients with COVID-19.
The WHO says Nasal High Flow should be used with airborne precautions.1

How is COVID-19 being managed?

The WHO is issuing the following information on clinical management of patients and the status of the outbreak:

The WHO refers to usage of Nasal High Flow therapy for pre-oxygenation prior to intubation and for non-invasive respiratory support with close monitoring for clinical deterioration in selected patients with hypoxemic respiratory failure.1

Most of the clinical experience with COVID-19 patients currently comes from clinicians in China, South Korea and Italy. Although reports vary, they include the requirement for treatment of viral pneumonia and hypoxemia.

A retrospective observational study published by Yang et al.3 reported the clinical course and outcomes of critically ill patients with COVID-19 in Wuhan. 

A recent publication4 in the Chinese Journal of Critical Care & Intensive Care Medicine from a group in Wuhan describes their treatment approach, which includes Nasal High Flow.

Another recent publication by Xie et al.5 in Intensive Care Medicine gives recommendations based on measures taken in China to deal with the shortfall of critical-care resources.

How to prepare for COVID-19

The WHO provides helpful information on COVID-19 preparation:

A recent publication7 in the Chinese Journal of Tuberculosis and Respiratory Medicine makes recommendations for prevention of the nosocomial transmission during respiratory care for critically ill patients infected by COVID-19.

Infection prevention and control

The WHO outlines additional precautions that should be taken to protect healthcare workers during aerosol-generating procedures associated with an increased risk of transmission6. These procedures include tracheal intubation, non-invasive ventilation, tracheotomy, cardiopulmonary resuscitation, manual ventilation before intubation and bronchoscopy.

Nasal High Flow is not specifically named by the WHO as an aerosol-generating procedure associated with an increased risk of transmission.6 However, there has been some uncertainty about the potential creation of aerosols from all forms of noninvasive respiratory support including Nasal High Flow.

According to the WHO: “Because of uncertainty around the potential for aerosolization, HFO, NIV, including bubble CPAP, should be used with airborne precautions until further evaluation of safety can be completed.” 1

Recent publications Hui et al.8, Leung et al.9 and Hui et al.10 compared the application of Nasal High Flow to a range of alternative therapies and interfaces and did not find increased risk of transmission via air dispersion. Collated air dispersion results from two studies conducted by Hui et al.8, 10 are illustrated in the chart below.

Findings of a new study by Kotoda et al.11 suggest that “high-flow nasal therapy does not increase the risk of droplet and contact infection”.

Changes in exhaled air dispersion | Hui

*Dispersion distance data shown on the chart is combined from two studies conducted by the same authors. 
Not all of the interfaces depicted were directly compared.

Clinical experience

The Handbook of COVID-19 Prevention and Treatment was compiled according to clinical experience with COVID-19 from The First Affiliated Hospital, Zhejiang University School of Medicine, in Hangzhou, the capital of China’s Zhejiang province.

AIRVO™ 2 and Optiflow™ + nasal cannula support

AIRVO™ 2  Introduction

AIRVO 2 (Part 1):

A description of what the AIRVO 2 is, how it works, and the philosophy behind the use of an active heated humidifier to provide Optimal Humidity. 


AIRVO™ 2  Set-up

AIRVO 2 (Part 2):

A step-by-step guide to setting up the AIRVO 2, and an introduction to our range of interfaces. 


AIRVO™ 2  Use

AIRVO 2 (Part 3):

How to operate the AIRVO 2, including guidance on how to adjust key settings such as flow, temperature, and how to add supplemental oxygen (if required). 


AIRVO™ 2  Reprocessing

AIRVO 2 (Part 4):

How to clean and disinfect the AIRVO 2, reprocessing it through high-level disinfection for use on the next patient. 


Optiflow+ Fitting video

Fitting the Optiflow + Nasal Cannula

Learn how to effectively fit the Optiflow + nasal cannula by watching this instructional video.

Optiflow + Nasal Cannula Fitting Guide

Learn how to effectively fit the Optiflow + nasal cannula by downloading the Fitting Guide.

Flow Matters | Edition 10

Updated Friday, 20 March 2020, 2:23PM (NZDT)

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AIRVO 2 and COVID-19

Updated Tuesday, 24 March 2020, 4:27PM (NZDT)

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