As a result of prospective, randomized clinical trials, another option has emerged for the patient with hypoxemic respiratory failure. The High- flow Nasal Cannula (HFNC) is a medical device used to provide supplemental oxygen or increased airflow to a patient in need of respiratory support. This device entails a lightweight tube that on one end splits into two prongs which are placed in the nostrils. And from which a mixture of air and oxygen flows. In addition other end of the tube is connected to an oxygen supply such as a portable oxygen generator, or a wall connection in a hospital via a flowmeter.

What is Non-Invasive Ventilation?

Noninvasive ventilation (NIV) refers to the administration of ventilatory support without using an invasive artificial airway (endotracheal tube or tracheostomy tube). The use of noninvasive ventilation (see the video below) has markedly increased over the past two decades, and noninvasive ventilation has now become an integral tool in the management of both acute and chronic respiratory failure, in both the home setting and in the critical care unit. Noninvasive ventilation has been used as a replacement for invasive ventilation, and its flexibility also allows it to be a valuable complement in patient management. Its use in acute respiratory failure is well accepted and widespread. It is the focus of this review. The role of noninvasive ventilation in those with chronic respiratory failure is not as clear and remains to be defined.

What is the use of HFNC ?

The use of heated and humidified high flow nasal cannula (HFNC) has become increasingly popular in the treatment of patients with acute respiratory failure through all age groups. Earlier it was used to treat children with severe bronchiolitis but now a days healthcare unit began to use it in the adult intensive care unit as well. 

Mechanism behind HFNC

Heat and humidified high flow nasal cannula or as most call it, Hi Flow Nasal Cannula (HFNC), isn’t just a standard nasal cannula cranked up to very high flow rates. It actually takes gas and can heat it to 37 o C with a 100% relative humidity and can deliver 0.21 – 1.00% fi02 at flow rates of up to 60 liters/min. The flow rate and fi02 can be independently titrated based on your patient’s flow and fi02 requirements.

It depends on various key factors which are describes below:

Heated & Humidified: Heated and Humidified oxygen has a number of benefits compared to standard oxygen therapy. Standard oxygen therapy delivered through a nasal cannula or another device such as a non-rebreather. This can lead to airway inflammation, which can increase airway resistance and impair mucociliary function. This may possibly leading to decrease secretion clearance.

Inspiratory Demands: One obvious benefit, but worth mentioning is that high flow can give you a very high flow of gas. This is important as patients in acute respiratory failure can be extremely tachypneic. Therefore their peak inspiratory flows, which may normally be 30L/min – 60L/min, can reach up to 120 L/min.

Lighter: Patients often prefer the use of HFNC to that of non-invasive positive pressure ventilation (CPAP or BPAP) because the tight fitting mask can be uncomfortable to some patients. They may even prefer it to standard NC. Because the warmed, humidified gases won’t dry their mucosa like standard oxygen therapy. This may lead to higher compliance with HFNC and perhaps an improvement in your patient’s oxygenation and work of breathing.

O2 Dilution: To deliver higher amounts of fiO2 effectively to your patient you have to not only match, but exceed your patient minute ventilation and inspiratory demands to minimize oxygen dilution.

This table represents the

Washout of Dead-space: We normally rebreathe a third of our previously expired tidal volume. Instead of breathing 21% (room air) and negligible amounts of carbon dioxide; we may rebreathe more like 15-16% oxygen and 5-6% carbon dioxide. This is because of previously exhaled breath (low in oxygen and with some carbon dioxide). And is not fully exhaled and remains in the upper airway.

When you patient takes their next breath from atmospheric gas not all of that gas enters the alveoli. In fact it’s a mix of the new atmospheric gas (21% 02, negligible CO2) and their previously exhaled gas (<21% oxygen and some CO2). In patients with acute respiratory failure, the percentage of gas we rebreathe gets larger. As a result we can rebreathe larger amounts of carbon dioxide. Another way to say this is our dead-space increases with acute respiratory failure.

Benefits of HFNC

We can clearly see the major benefits of HFNC as written below:

The 5 best-selling HFNC machines

  1. Fisher & Paykel AIRVO 2 Humidification High Flow System

Brand name: Fisher & Paykel

Model: AIRVO 2

Price Range: 70,000- 1 lakh

Product Details:

  • Airvo 2 has been proven to be effective in patients with acute hypoxemic respiratory failure, for post-extubation respiratory support, for postoperative respiratory support, for immunocompromised patients with acute hypoxemic respiratory failure and for patients with COPD.
  • A broad flow range (2 to 60 L/min) takes your patients from the most acute environments (ICU and ED) to the home.
  • A compact system with a built-in flow generator means there’s no need for a noisy, heavy air compressor in order to use the Airvo 2 for transport.
  • Three temperature settings, (37, 34, 31 °C) helps achieve comfort and compliance.
  • A variety of interfaces specifically designed with Optiflow High Flow therapy in mind. At higher flows comfort is paramount – you need an interface designed for the job.
  • AirSpiral heated breathing tube with integrated dual-spiral heated wires and temperature sensor.
  • No separate temperature probes or adapters required.

2. BMC H-80M Series High Flow oxygen Therapy Humidifier

BMC new H-80M Series high-flow oxygen therapy, highly integrated design, to meet more needs of clinical treatment. H-80M Series High Flow Oxygen Therapy can be used for patients with spontaneous breathing, including artificial airway respiratory insufficiency, and can be used for patients in hospitals and long-term care institutions.

Brand name: BMC

Model number- H-80M Series

Price Range- 1.5- 2 lakh

Product Specifications:

  • Flow Rate: 2L-80L/min
  • Oxygen Concentration Adjustable Range: 21%-100%
  • Weight: 2.5kg
  • Screen Size: 3.5 inches

3. Comen HF5 HFNC High Flow Heated Respiratory Humidifier

Provide a certain flow, heated and humidified fresh gas for treatment, and provide SpO2 monitoring. For patients with spontaneous breathing, these patients include patients with humidification therapy, oxygen therapy, tracheal intubation and tracheotomy.

HFNC generates variable airway pressure through a constant flow rate of fresh gas CPAP is to generate constant airway pressure by changing the flow rate of fresh gas.

Brand: Comen

Model: HF5

Price Range: 2- 3 lakh

Product Specifications:

  • Ultra- Large touch screen: NF5 is equipped with a 4.3- inch
    touch screen, which allows easy and quick operation by
    touch and navigation knob.
  • Electronic Air- O2 mixer system: easy to set up flow rate
    and O2 concentration.
  • Intuitive UI design: large font, easy for caregiver to
    operate and observe.
  • Flow Rate: 80 L/ min
  • It has Turbine Base & Electronic Blender

4. Respicare HFNC machine

The high-flow respiratory humidification therapy instrument (HFNC) breaks through the shortcomings of traditional oxygen therapy. It can not only provide heated and humidified oxygen with a flow rate of up to 60L/min, but also accurately adjust the oxygen concentration.
The high-flow respiratory humidification treatment instrument is a new oxygen therapy method. The device is composed of an air-oxygen mixer, an active humidifier, a single heating circuit, a large-diameter nasal congestion catheter or a tracheostomy connector, and a mask adapter.

Brand: Respicare


Price range: 3.35- 4 lakh

Product specifications:

  • Power supply: 220VAC+22V,50+1Hz
  • Flow setting range: Low Flow Mode:2-25L /Min temp:34℃, High Flow Mode:10-80L/Min
  • Temperature Control: 31℃ ,34℃ ,37°C
  • Oxygen% Measure: 21 %-100%
  • Recommended Ambient Temp. : 18-28°C
  • Alarm parameters: Low oxygen concentration alarm, High oxygen concentration alarm, Choke alarm

Main features:

  • Keep constant precise high FiO2 and improve the alveolar ventilation
  • Improve the efficiency of breathing by reduction of anatomical dead space and replacing it with oxygen-enriched gas in the upper airway.
  • Low levels of PEEP may contribute to collapsed alveolar recruitment
  • Good humidity promote effective from the sputum and mucociliary clearance to reduce the risk of infection
  • More comfort , Better tolerance and Greater respiratory compliance in the patients.

5. Allied Medical Jupiter High Flow Oxygen Cannula Therapy Device

Allied Jupiter HFNC device is a versatile and stable solution for the hospitals and healthcare providers to deliver high flow rates of Oxygen accurately and precisely to the Patient. It has been proven to give solid results for the management of patients with hypoxemic respiratory failure. The system supplies heated and humidified gas to the patient thus improving patient’s tolerance and comfort. This device facilitates the wash out of anatomical nasopharyngeal cavity, dead space carbon dioxide, improving the efficiency of oxygen delivery.

Brand: Respicare

Price range: 2- 3 lakh

Product Specifications:

  • Built-in Turbine Technology 
  • Inspiratory Flow Rate- 0 –80 L/Min
  • Oxygen Concentration 21-100%
  • Built-in Oxygen Sensor
  • Power Supply – 220V-240 VAC 50 Hz
  • Internal battery backup: 2 Hrs.
  • Main Unit Weight- 4.5 Kgs.

Frequently Asked Questions

Q1. Is HFNC a ventilator?

HFNC is different from BIPAP or non invasive ventilator because it provides high flow oxygen along with pressure which relieves the air hunger of the patient. It is different from a ventilator as the patient is conscious and there is no tube in the patient’s lungs.

Q2. What is the difference between NIV and HFNC?

HFNC can provide continuous oxygen up to 70L/min via nasal prongs with the potential advantage of remaining in place for apneic oxygenation. NIV can also provide high flow oxygen but must be removed during the apneic phase of intubation.

Q3. What is the maximum flow rate for a high-flow nasal cannula?

The HFNC overcomes flow limitations of low- and intermediate-flow devices by delivering up to 60 liters per minute of heated, humidified gas via nasal prongs.

Q4. What is sp02?

SpO2, also known as oxygen saturation, is a measure of the amount of oxygen-carrying hemoglobin in the blood relative to the amount of hemoglobin not carrying oxygen. The body needs there to be a certain level of oxygen in the blood or it will not function as efficiently.

Q5. When is HFNC used?

The indications for the use of HFNC in adults include community-acquired pneumonia, post-extubation (even in low-risk patients), pre-oxygenation prior to intubation, DNI patients with respiratory failure, and perhaps in patients with cardiogenic pulmonary edema when NIPPV is not tolerated.


HFNC is a simple system with clinical effects mainly dependent on flow, oxygen concentration, and temperature setting. Usually, end-inspiratory lung volume increases as flow increases. Greater flow also washes out more anatomic dead space. For patients with acute hypoxemic respiratory failure, the HFNC gas temperature may affect comfort: at equal flows, there is evidence that lowering the temperature to 31°C can be more comfortable than 37°C.Patients with more-severe hypoxemia find higher flows more comfortable. Although the functional differences between various HFNC systems are minor, it is essential to prevent rainout in the inspiratory circuit to avoid adverse clinical events. Another HFNC issue in the clinical setting is noise. This needs to be successfully addressed to provide optimal care for patients.