Journal of Clinical and Scientific Research

: 2018  |  Volume : 7  |  Issue : 1  |  Page : 47--48

High-flow nasal cannula oxygen therapy: An alternative means of respiratory support for critically ill patients

Hemanth Natham, Madhusudan Mukkara 
 Department of Anaesthesiology and Critical Care, Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh, India

Correspondence Address:
Hemanth Natham
Associate Professor, Department of Anaesthesiology and Critical Care, Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh

How to cite this article:
Natham H, Mukkara M. High-flow nasal cannula oxygen therapy: An alternative means of respiratory support for critically ill patients.J Clin Sci Res 2018;7:47-48

How to cite this URL:
Natham H, Mukkara M. High-flow nasal cannula oxygen therapy: An alternative means of respiratory support for critically ill patients. J Clin Sci Res [serial online] 2018 [cited 2020 May 27 ];7:47-48
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Full Text

First-line treatment for hypoxaemic respiratory failure is supplemental oxygen. Administered via an air–oxygen blender, active heated humidifier, single heated circuit and nasal cannula, high-flow nasal cannula oxygen therapy has been gaining attention as an alternative means of respiratory support for critically ill patients. High-flow nasal oxygen therapy (HFNOT) is increasingly used as part of both ward-based and critical care management of respiratory failure. It is considered to have a number of physiological advantages compared with other standard oxygen therapies, including reduced anatomical dead space, positive end-expiratory pressure (PEEP), constant fraction of inspired oxygen concentration (FIO2) and good humidification. The ability of nasal cannulae to provide positive pressure to the airways was first noted in neonates, and it is in this patient group that this therapeutic effect was first used. A similar continuous positive airway pressure effect, with higher flows, was noted in adults,[1] and from here, HFNOT was developed.[2] HFNOT provides warmed, humidified gases at flows of up to 60 L/min, with inspired oxygen concentrations of up to 100%.

There are different devices available for the provision of high flow, humidified oxygen via nasal cannulae. The devices consist of nasal cannulae with standard sized or wide-bore prongs connected to an oxygen flow meter with an air–oxygen gas blender and a gas analyser [Figure 1]. They offer maximum gas flow rates of between 40 and 60 L/min, depending on the device.{Figure 1}

A heating system and humidifier allows delivery of gases at temperatures of between 33°C and 43°C and 95%–100% humidity. Some patient interfaces have soft contoured, wide-bore nasal prongs designed to reduce gas jetting, while others are used with traditional narrow-bore nasal cannula. The interfaces are intended for single patient use, with a maximum duration of use of 30 days. Humidity is provided by a disposable vapour transfer cartridge, a bubble humidifier or a heated plate humidifier.[3] The triad of humidity, compliance and high FIO2 that HFNOT offers is likely to be of use in a wide variety of clinical situations. This is a rapidly evolving area, and the evidence for its use in acute hypoxaemic respiratory failure, advanced airway management and the postoperative population is growing.

 Clinical Indications

Acute hypoxaemic respiratory failure

HFNOT is useful for the treatment of acute respiratory failure (ACRF) due to its ability to provide an FIO2 of close to 1, PEEP of 5 cm H2O and humidified gases through a comfortable interface. HFNOT can be particularly useful in ACRF patients with increased work of breathing who do not tolerate face mask therapy or those who have a high secretion load. HFNOT has also been used in patients with hypoxaemia due to cardiogenic pulmonary oedema, where the application of PEEP resulting from HFNOT led to improvment in dyspnoea and arterial oxygentension.[3]

Airway management

Recent attention has focused on the use of HFNOT in the difficult airway and its ability to increase the time to desaturation and decrease the severity of the desaturation in anaesthetised patients; obstetric, bariatric and septic patients represent potential groups where pre-oxygenation with HFNOT may be beneficial.[4] It is important to remember that periods of apnoea in excess of 15 min can be achieved with HFNOT, but arterial CO2 levels may increase to dangerous levels, resulting in severe acidosis.[4]

Extubation and post-operative use

It has been shown that HFNOT is not inferior in preventing re-intubation compared with Non-invasive ventilation (NIV) in obese patients undergoing cardiac surgery.[5]


Contraindications to the use of HFNOT are much the same as for NIV delivered via a face mask or hood. HFNOT should not delay mechanical ventilation in those with severe respiratory failure, particularly in type II respiratory failure. Any contraindication to the application of PEEP should prompt alternative methods of respiratory support to be sought. In addition, it should not be used on those with reduced levels of consciousness or uncooperative patients.

 Current Status

High-flow oxygen therapy is commonly used on patients with ARF (hypoxemic respiratory failure) in the hospital system. It has been used successfully in chronic obstructive pulmonary disease, bronchiectasis, end-stage cancer and do-not-intubate patients. In the future, it may be used more frequently in hospital wards to help in decreasing admission to intensive care units.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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3Ward JJ. High-flow oxygen administration by nasal cannula for adult and perinatal patients. Respir Care 2013;58:98-122.
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