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Is nasal high flow (NHF) suitable for treating patients with hypercapnic respiratory failure?

The facts about the impact of NHF on C02:

  • NHF reduces rebreathing of gas high in CO2 and oxygen-depleted - see the effect in action in the video below - on the left) 
  • The degree of dead space reduction appears to be flow-dependent (Moller et al. 2015) - see the graph below - on the right. 
Optiflow High Flow deadspace mechanism overview
NHF has been proven to reduce PaCO2 in COPD patients. Pantazopoulos et al. 2020. provides a review of the literature and proposes a treatment algorithm for COPD patients.

So, if the patient is:
  1. spontaneously breathing
  2. may benefit from a reduced PaCO2 or any of the other benefits of NHF
  3. is not otherwise indicated for mechanical ventilation (see guidance docs below)

NHF may be a suitable treatment.

Emerging guidelines address the efficacy in various populations, see below. 

Evidence-based clinical practice guidelines


Hundreds of randomized controlled trials have been consolidated into clinical practice guidelines. 

These guidelines underscore the breadth of application of nasal high flow therapy.

We’ve created a table that will help you review the  guidelines by patient population and application.


Explore the NHF guidelines table