High-flow nasal cannula (HFNC), also referred to as nasal high flow (NHF), is a therapy that has gained traction in the past decade and is sometimes lumped together with the use of noninvasive ventilation (NIV). Since it differs from noninvasive ventilation, it will be important to highlight differences between these two therapies.
Oxygen delivery with HFNC
Let’s take a moment to remember the traditional nasal cannula. When connected to wall oxygen, this cannula can deliver oxygen at flow rates from 1 to 6 L / min for extended periods of time. Higher flow rates are not well tolerated due to nasal irritation and discomfort.
High-flow nasal cannula, or HFNC, is a system that allows oxygen to be delivered to patients at very high flow rates. In adults, it can be titrated from 20 L / min up to 60 L / min! By using specialized nasal cannulas, heating the circuit to body temperature and humidifying the air, these high rates can be delivered with very good patient tolerance.
Like the flow rate, fraction of inspired oxygen (FIO2) can be precisely titrated as well. An air-oxygen blender can take 100% wall oxygen, mix it with room air, and deliver a FIO2 between 21 and 100%.
How is HFNC like NIV?
HFNC is similar to NIV in that it reduces the entrainment of room air and allows a more precise amount of oxygen to be delivered. It requires a specialized interface that sits in the nose with larger bore openings. It can provide respiratory support to patients with respiratory failure due to hypoxia.
How does HFNC differ from NIV?
HFNC differs to NIV in that it provides less ventilatory support. You set a flow rate instead of setting inspiratory and expiratory pressures. Therefore, the pressure produced from HFNC flow rates is much lower in comparison to NIV.
When should I avoid the use of HFNC?
Do not use high-flow nasal cannula, or HFNC, in patients with:
- Ventilatory failure
That’s it for now. If you want to improve your understanding of key concepts in medicine, and improve your clinical skills, make sure to register for a free trial account, which will give you access to free videos and downloads. We’ll help you make the right decisions for yourself and your patients.
- Dysart, K, Miller, TL, Wolfson, MR, et al. 2009. Research in high flow therapy: mechanisms of action. Respir Med. 103: 1400–1405. PMID: 19467849
- Frat, JP, Thille, AW, Girault, C, et al. 2015. High-flow oxygen through nasal cannula in acute hypoxemic respiratory failure. N Engl J Med. 372: 2185–2196. PMID: 25981908
- Hernández, G, Vaquero C, Colinas, L, et al. 2016. Effect of postextubation high-flow nasal cannula vs noninvasive ventilation on reintubation and postextubation respiratory failure in high-risk patients: a randomized clinical trial. JAMA. 316: 1565–1574. PMID: 27706464
- Hernández, G, Vaquero C, González, P, et al. 2016. Effect of postextubation high-flow nasal cannula vs conventional oxygen therapy on reintubation in low-risk patients: a randomized clinical trial. JAMA. 315: 1354–1361. PMID: 26975498
- Maggiore, SM, Idone, FA, Vaschetto, R, et al. 2014. Nasal high-flow versus venturi mask oxygen therapy after extubation. Effects of oxygenation, comfort and clinical outcome. Am J Respir Crit Care Med. 190: 282–288. PMID: 25003980
- Mauri, T, Turrini, C, Eronia, N, et al. 2017. Physiologic effects of high-flow nasal cannula in acute hypoxemic respiratory failure. Am J Respir Crit Care Med. 195: 1207–1215. PMID: 27997805
- Roca, O, Caralt, B, Messika, J, et al. 2019. An index combining respiratory rate and oxygenation to predict outcome of nasal high-flow therapy. Am J Respir Crit Care Med. 199: 1368–1376. PMID: 30576221
- Roca, O, Messika, J, Caralt, B, et al. 2016. Predicting success of high-flow nasal cannula in pneumonia patients with hypoxemic respiratory failure: the utility of the ROX index. J Crit Care. 35: 200–205. PMID: 27481760
- Sztrymf, B, Messika, J, Bertrand, F, et al. 2011. Beneficial effects of humidified high flow nasal oxygen in critical care patients: a prospective pilot study. Intensive Care Med. 37: 1780–1786. PMID: 21946925