Pediatric nasal
high flow therapy

Nasal high flow (NHF) is a mode of noninvasive respiratory support that delivers high flows of blended air and oxygen through a nasal interface.1

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Optiflow Junior 2 Nasal interface

Optiflow™ Junior 2

A non-sealing nasal interface specifically designed for the flow requirements and anatomical features of infants and children on NHF therapy.

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How does NHF therapy work?

NHF is a flow-based therapy designed to be an open system that typically consists of a flow source to blend air and oxygen, a humidifier to heat and humidify the gas mixture, and a circuit and interface to deliver humidified gas to the patient. Suitable sizing of the nasal cannula is important to ensure the open system is maintained.

NHF is associated with a range of mechanisms of action and physiological benefits:

Ensures washout of anatomical dead space.2-4
Provides dynamic positive airway pressure.2-5
Delivers heated and humidified gas.6-9
Provides supplemental oxygen.10-12
Improves patient comfort.13-16

Comparison of NHF vs Unassisted Breathing
Ensures washout of anatomical dead space

The washout of anatomical dead space improves pulmonary gas exchange through the clearance of CO2 in the upper airways. This ultimately reduces the work of breathing.2

Unsupported breathing
There is a high concentration of CO2 in the nasopharynx following exhalation, which is re-breathed on inspiration. This increases the work of breathing to compensate for poorer lung oxygenation.3

Using NHF
The continuous flow of fresh gas washes out CO2-rich gas from the nasopharynx. This decreases the amount of CO2 re-breathed on inspiration.

As a result, pulmonary gas exchange and oxygenation are improved and the work of breathing is reduced.2,4

This featured animation is based on a conceptual model of breathing that describes flushing of the upper airway, with and without NFH.2-4

Dynamic Positive Airway Pressure
Provides dynamic positive airway pressure

With NHF, flow is prescribed and set. A level of dynamic positive airway pressure is generated because of the flow, which is dependent on a range of factors such as the weight of the infant, the set flow rate and nare occlusion.2,4

It is important the nasal cannula does not create a seal in the nares so NHF is maintained as an open system.

The dynamic positive airway pressure associated with NHF has been shown to reduce inspiratory effort and the work of breathing compared with standard oxygen therapy.2,4,5

Adapted from Milési et. al., 2013, the animated graph we feature here shows how positive pressure during inspiration reduces the inspiratory work of breathing.

Delivers heated and humidified gas

NHF delivers a heated and humidified blend of air and oxygen, maintaining the nasal mucosa and enhancing mucociliary function.6 It reduces mucosal dryness and improves secretion clearance compared with standard oxygen therapy.7 Consensus guidelines state that NHF should always be adequately heated and humidified.8,9

Learn more about humidity

Provides supplemental oxygen

NHF differs from standard oxygen therapy in that it can accurately deliver a prescribed FiO2 when the set flow rate meets or exceeds a patient’s peak inspiratory demand.10,11

FiO2 is the proportion of oxygen in the air that is inspired.11 In addition to the ability to deliver accurate FiO2, the combined mechanisms of NHF have the effect of improving oxygenation status.10-12

Compared with standard oxygen therapy, NHF can accurately deliver a prescribed FiO2 when set flow meets or exceeds the patient's peak inspiratory demand.

Improves patient comfort

Because NHF is an open system, it is gentle on the patient’s nose.

Compared with continuous positive airway pressure (CPAP), NHF improves patient comfort, compliance and tolerance to therapy.13,14 NHF is also associated with a significant reduction in the rate of nasal trauma.15,16

Clinical NHF studies have used objective measures, such as heart rate, facial expressions, and movement, to assess patient comfort.14
Flow Matters Pediatric edition thumbnail

Updated March 2023

Optiflow Flow Matters

Early use of NHF in infants and children

In our pediatric edition of Optiflow™ Flow Matters, we review the literature and provide an evidence-based approach to the implementation of NHF in pediatric patients.

Read online

Download PDF

Setting flow rates for infants and children

Clinical evidence supports a dose-by-weight approach with suggested flow rates of about 2 liters per kilogram per minute (L/kg/min) for infants between 3.0 and 12.5 kilograms.4,7-12
Weight Flow rate Flows
Up to 12 kg 2 L/kg/min
Up to 12 kg
2 L/kg/min for infants up to 12 kg in weight has been shown to produce rapid improvement in reducing respiratory distress, and a reduced need for the escalation of therapy.

Over 12 kg Flow rates for those over 12 kg in weight have been protocolized by the PARIS research group.4
13 – 15 kg 25 – 30 L/min
16 – 30 kg 35 L/min
31 – 50 kg 40 L/min
> 50 kg 50 L/min

The Queensland Children's Hospital NHF Documentary Series

The Queensland Children's Hospital (formerly Lady Cilento Children's Hospital) in Australia, shares its successful implementation of NHF therapy for infants and children.
A new therapy in practice at Lady Cilento Children’s Hospital

NHF therapy in practice in a children's hospital

Explore how the Queensland Children's Hospital uses NHF therapy across the hospital.
The impact of a new therapy at Lady Cilento Children’s Hospital

The impact of NHF therapy

Discover how the Queensland Children's Hospital successfully implemented NHF therapy.

Implementing a new therapy at Lady Cilento Children’s Hospital

The research behind NHF implementation

Learn about the research that led to the implementation of NHF therapy at the Queensland Children's Hospital.

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