Is there a protocol for use of Nasal High Flow?

Ischaki 2017, European Respiratory Review.

Ischaki proposed the following algorithm for use on patients with acute hypoxemic respiratory failure.

Ischaki 2017 European Respiratory Review
Open "Flow Matters" featuring Ischaki Take me to the PubMed abstract
  1. Ischaki E, Pantazopoulos I, Zakynthinos S. Nasal high flow therapy: a novel treatment rather than a more expensive oxygen device. Eur Respir Rev. 2017;26(145):170028.

Adapted from above original paper; used under Creative Commons licence 4.0. MV = mechanical ventilation; SOT = standard oxygen treatment.
Please note: this material is intended exclusively for healthcare practitioners and the information conveyed constitutes neither medical advice nor instructions for use. This material should not be used for training purposes or to replace individual hospital policies or practices. Before any product use, consult the appropriate user instructions.


What flow rates are typical for Nasal High Flow use?

The following table lists starting flows and flow ranges used in clinical studies for Optiflow HF therapy.

Flow distress and chronic graph
  1. Macé J, Marjanovic N, Faranpour F, Mimoz O, Frerebeau M, Violeau M, et al. Early high–flow nasal cannula oxygen therapy in adults with acute hypoxemic respiratory failure in the ED: A before–after study. Am J Emerg Med. 2019 Mar 5. [Epub ahead of print]

Flow Matters

Edition 11 (August 2020)

What systems and settings are used in NHF research?

Surveys of the studies comprising the body of NHF evidence found the majority used F&P Optiflow systems and flow settings between 45 and 60 L/min.
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How much pressure is generated by Nasal High Flow?

Average pressure increases approximately 0.5 - 1 cmH2O per 10 L/min.

Airway Pressure Graph

Pressure ranges are cannula and patient dependent. For illustrative purposes only. 

  1. Ritchie JE, Williams AB, Gerard C, Hockey H. Evaluation of a humidified nasal highflow oxygen system, using oxygraphy, capnography and measurement of upper airway pressures. Anaesth Intensive Care. 2011; 39(6):1103–10.

How quickly does Optiflow Nasal High Flow work?

Sztrymf associated Optiflow HF therapy with sustained beneficial effects on oxygenation and physiological
parameters for patients with acute respiratory failure. Similarly Rittayamai showed significant improvement
in post-extubation patients. These studies may provide guidance on patient responses to the therapy.

  1. Rittayamai N, Tscheikuna J, Praphruetkit N, Kijpinyochai S. Use of High-Flow Nasal Cannula for Acute Dyspnea and Hypoxemia in the Emergency Department. Respir Care. 2015; 60(10):1377–82.

Is there a bedside tool that provides an indicator of Nasal High Flow outcomes?

The validated ROX index provides an indicator of outcomes in adults with AHRF receiving Nasal High Flow therapy.

4 time intervals are observed: 2, 6, 12 and >12 hours. It's an easy-to-use dynamic bedside tool.

Calculating a ROX score
  1. Roca O, Caralt B, Messika J, Samper M, Sztrymf B, Hernandez G, et al. An Index Combining Respiratory Rate and Oxygenation to Predict Outcome of Nasal High Flow Therapy. Am J Respir Crit Care Med. 2018 Dec 21. [Epub ahead of print]

A tool to help monitor your Nasal High Flow patients 

Using just 3 data points (SpO2, respiratory rate and FiO2) the validated ROX Index* provides an indicator of NHF outcomes in adults experiencing acute hypoxemic respiratory failure due to  (non-COVID) pneumonia.

The ROX Index explained

Edition 9
(updated August 2020)

Read now Download PDF

App new icon

Download the F&P ROX index calculator app

ROX app

Who does Nasal High Flow work on?

The short answer is spontaneously breathing patients with, or at risk of respiratory distress.

Is your patient presenting with:






Respiratory Rate


Work of Breathing



The key to really understanding who can benefit from HF is in understanding the mechanisms of HF. 



What effect does low humidity have on the airway?

Optiflow High Flow airway hydration mechanism overview


Even a 10% drop in humidity (in the airway) can have a detrimental effect on mucociliary clearance transport, a crucial part of the upper airway defense system.

What next?

F&P Optiflow™+ Nasal Cannula

Optiflow™ Nasal High Flow at the Royal Berkshire Hospital

Introducing Optiflow to the Royal Berkshire Hospital


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