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Oxygen - humidified high flow oxygen or air for neonates

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Humidified High-Flow (HHF) oxygen/air is a form of respiratory support in preterm infants where their breathing is spontaneous. It is air-oxygen flow (via blender) of 1-6 L/min via the Fisher & Paykel humidifier.


HHF is utilised in NICU for infants with mild respiratory dysfunction. HHF should only be used on infants after discussion with the overseeing Consultant and may be relevant for infants who:

  • Are 34-36 weeks corrected gestational age 
  • Are HCPAP (6cmH2O) dependant 
  • Have an FiO2 requirement of <0.3 
  • Are not deemed stable enough to be trialled self ventilating in Air 
  • Are not of a gestation where Low-flow may be more appropriate. See Low Flow Oxygen &/or Air Protocol 

HHF effects include:

  1. HHF provides a warmed and humidified flow of air and/or air-oxygen mixture (via a blender) to the infant where FiO2 can be monitored.
  2. There is some degree of end distending pressure involved in HHF; however, debate remains as to how much.
  3. HHF may be better tolerated by infants becoming unsettled with HCPAP.
  4. Reduced gastric distension3.
  5. Sucking feeds and Kangaroo care are more easily attempted with HHF than HCPAP.


  1. Potential for asynchrony in breathing may result in the infant becoming tired over long periods; therefore, good assessment of work of breathing is required. 
  2. Potential for nasal erosion (although less than with HCPAP) remains. 
  3. There is some concern about unknown end distending pressure and varied results gained in research studies; therefore ensure that the prongs do not seal the nares and reduce flow as able. 
  4. "Rainout" in circuit resulting in lavage and apnoea. Use designated circuit (RT330) and check for "rainout" regularly, draining circuit as required 

Application of Humidified High Flow (HHF)

HHF is to be commenced at a flow rate of 5 L/min and can be increased to 6 L/min after consultation with registrar/NS-ANP. The infant should be returned to HCPAP for increasing work of breathing or increasing apnoea/bradycardia/desaturation or high carbon dioxide on a blood gas.

If cycling of HHF and CPAP is being utilised:

  • HHF should be administered during the day allowing for increased parental interaction and sucking feed attempts. 
  • HCPAP should continue at night time. 
  • HCPAP and HHF have different tubing and pressure relief valves (HCPAP white/HHF blue), so the entire system needs to be alternated. 
  • The same humidifier base may be utilised. 

NB. The blue HHF pressure relief valve blows off at 40 cm of H2O pressure

To Commence HHF on an Infant

  1. Select appropriate size optiflow nasal cannula:
    - Premature (Red - 8 g) - for babies 700-1250 g
    - Neonatal (Yellow - 10 g) - For babies 1250-3000 g
    - Infant (Purple - 13 g) do not use on babies less than 2800 g
  2. Assemble equipment
    - HHF set (RT330)
    - Humidifier base, filter, temperature probe, oxygen tubing and oxygen analyzer
  3. Calibrate oxygen analyzer
  4. Prepare the optiflow nasal cannula for application
  5. The swivel connector of the Optiflow Nasal Cannula may be connected (clicked into) to the blue tubing before application. This allows humidified high flow oxygen/air to be given while the cannula is being applied
  6. Remove the paper protector from the nasal aspect of the wiggle pads (base tape)
  7. Ensure baby's skin is dry
  8. Check baby's septum integrity
  9. Insert one prong into each nostril so that the bridge is just touching the septum
  10. Holding the cannula/wiggle pad wings, apply slight tension so as to straighten the bridge of the cannula then fix the nasal aspects of the wiggle pads onto the baby's cheeks
  11. On one side lift the outer edge of the wing and holding the paper tab remove the paper and press the wiggle pad into place. Do the same on the other side
  12. Ensure that the wiggle pads are situated horizontally across the cheeks
  13. Once the cannula is applied check that the bridge has naturally moved 2mm away from the septum
  14. With the cannula in position squeeze baby's cheeks slightly together to be sure that the cannula is not going to pop out of the nares. If the cannula pops out remove the cannula from the wiggle pads (which are adhered to baby's cheeks) and repeat the steps 9 and 10 fixing the cannula back onto the attached wiggle pads
  15. Remember the correct sized Optiflow Nasal Cannula does not occlude the nares. This is not CPAP
  16. Be sure that the baby, particularly baby's ears are not lying on the Optiflow Cannula's coil tubing
  17. Baby must be monitored at all times
  18. Change the cannula and circuit every 7 days
  19. The plastic clip is utilised to hold the blue tubing in place when the baby is up for Kangaroo cuddles. It may also be utilised in the incubator or cot.










See Humidification Protocol-Circuit Management for further information


  • Do not use a chin strap with High flow. Active mouth closure is not required.
  • Watch for "rain-out as this can cause a lavage to the infant resulting in apnea.
  • The baby may be nursed prone, skin to skin (kangaroo cuddle), supine or side to side lying.
  • Infants may be offered breast of bottle feeds whilst on HHF.


  • Once an infant is continuously utilising HHF the FiO2 should be weaned as able to 0.3, then the flow weaned over a number of days, under the guidance of the overseeing consultant.
  • Once the flow has been weaned to <1L/min it is now considered Low-Flow. It will continue to be warmed and humidified until the flow is <300ml/min

See also CPAP Protocol


  1. Wilkinson, D., Andersen, C., Smith, K. & Holberton, J. Pharyngeal pressure with high-flow nasal cannulae in premature infants. Journal of Perinatology. 2008: 28(1), 42-47.
  2. Wilkinson D., Anderson C., O'Donnell CPF., De Paoli AG. High Flow nasal cannula for respiratory support in preterm infants (Review) The Cochrane Collaboration. The Cochrane library 2011, Issue 5, 1-32
  3. Sivieri, EM., Gerdes, JS., Abbasi, S. Effect of HFNC Flow Rate, Cannula Size, and Nares Diameter on Generated Airway pressures: An In Vitro study. 2012. April 21. Wiley Periodicals, Inc. Published online:
  4. Manley, BJ., Owen, L., Doyle, LW., Davis, PG. High-flow nasal cannulae and nasal continuous positive airway pressure use in non-tertiary special care nurseries in Australia and New Zealand. Journal of Paediatrics and Child Health 48 (2012) 16-21
  5. Lampland, A., Plumm, B., Meyers, PA., Worwa, CT., Mamell, MC. Observational Study of Humidified High-Flow nasal Cannula Compared with Nasal Continuous Positive Airway Pressure. The Journal of Pediatrics. February 2009.
  6. Wilkinson, DJ., Anderson, CC., Smith, K., Holberton, J. Pharyngeal pressure with high-flow nasal cannulae in premature infants. Journal of Perinatology. 2008; 28: 42-47
  7. Shoemaker, MT., Pierce, MR., Yoder, BA., DiGeronimo, RJ. High flow nasal cannula versus nasal CPAP for neonatal respiratory disease: a retrospective study. Journal of Perinatology; 2007; 27(2): 85-91
  8. Woodhead, DD., Lambert, DK., Clark, JM., Christensen RD. Comparing two methods of delivering high-flow gas therapy by nasal cannula following endotracheal extubation: a prospective, randomized, masked, crossover trial. Journal of Perinatology 2006; 26(8); 481-485
  9. Wilkinson, DJC., Andersen, CC., Holberton, J. Should High flow Nasal Cannula Be Used for Respiratory support in Preterm Infants? Neonatology Today. 2008: Vol. 3/Issue 8.

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Document Control

  • Date last published: 30 April 2013
  • Document type: Clinical Guideline
  • Services responsible: Neonatology
  • Owner: Newborn Services Clinical Practice Committee
  • Editor: Sarah Bellhouse
  • Review frequency: 2 years