Overview

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

Indications

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

Are 34-36 weeks corrected gestational age
Are HCPAP (6cmH₂O) dependant
Have an FiO₂requirement 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:

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

Complications

Potential for asynchrony in breathing may result in the infant becoming tired over long periods; therefore, good assessment of work of breathing is required².
Potential for nasal erosion (although less than with HCPAP) remains.
There is some concern about unknown end distending pressure and varied results gained in research studies ^1,2,3,4; therefore ensure that the prongs do not seal the nares and reduce flow as able.
Potential problems with "rainout" resulting in lavage and apnoea; therefore, nurses need to be aware of clearing "rainout" from tubing regularly and ensuring that only heated tubing is utilised.

Application of Humidified High Flow

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.

Before Commencing HHF on an Infant

Select appropriate prong size (Infant vs Neonatal) and get HHF set (RT329).
Place duoderm strips to the infants cheeks and then apply strips of hyperfix attaching the prongs to the infants cheeks.

Ensure that extra (non heated) blue tubing is discarded.
See Humidification Protocol-Circuit Management for further information

Maintenance

Active mouth closure is not required¹
Watch for "rain-out" in the clear prong tubing as this can cause a lavage to the infant resulting in apnoea.
The baby may be nursed prone, skin to skin (kangaroo), supine or side to side lying.
Orogastric / nasogastric feeds are as ordered / tolerated
Infants may be offered breast or bottle feeds whilst on HHF but continual respiratory assessment is essential.

Weaning

Once an infant is continuously utilising HHF the FiO₂should 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

Nursing Care

Step	Action	Rationale
1.	Observe and document a baseline assessment of the infant prior to the commencement of HHF Respiration: rate, effort, breath sounds, signs of distress (tachypnoea, nasal flaring, sternal indrawing, rib retractions, grunting) Temperature Cardiovascular: central and pripheral perfusion, blood pressure, auscultation Neurological: tone, response to stimulation, activity Gastro-intestinal: specific characteristics (e.g. cleft palate, omphalocele), abdominal distension, visable loops, bowel sounds Technical: pre-ductal (preferably right arm) oxygen saturation probe, cardio-respiratory monitor	Baseline observations are essential to the ongoing management of the baby.
2	Regular observations as outlined above need to be preformed. Minimal handling is essential for the sick infant therefore "hands-on" intervention should be limited to 2-4hrly if possible.	Decisions regarding ongoing treatment are made on the basis of serial assessments.
3	Keep the baby's parents informed of what is happening. Answer questions and offer information, as you do with regard to all other aspects of the baby's care.	Parents are members of our care team and have the right to understand the care their baby receives.
4	Once the infant is stable on HHF and is tolerating handling without compromise or agitation, the usual activities of care can be performed.
5	Parents can be encouraged to participate by being shown the techniques of soothing and containment. They can perform oral cares, nappy changes, etc. as their confidence and baby's condition permits.	This facilitates attachment and reinforces their role as parent and caretaker.
6	Change the baby's position 4-6hrly. Kangaroo care is an ideal variation in position along with it's other tactile emotional advantages.	Changing position is a gentle way to move lung secretions along the airway.

References:

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	Saslow, J., Aghai, Z., Nakhla, T., Hart, J., Lawrysh, R., Stahl, G. & Pyon, K. Work of breathing using high-flow nasal cannula in preterm infants. Journal of Perinatology. 2006. 26, 476-480
3	Locke, R., Wolfson, M., Shaffer, T., Rubenstein, D. & Greenspan, J. Inadvertent Administration of Positive End-Distending Pressure During Nasal Cannula Flow. Pediatrics. 1993. 91(1), 135-138
4	Screenan, C., Lemke, R., Hudson-Mason, A. & Osiovicj, H. High-Flow Nasal Cannulae in the Management of Apnea of Prematurity: A Comparison with Conventional Nasal Continuous Positive Airway Pressure. Pediatrics. 2001. 107(5), 1081-1083.

Humidified High Flow Oxygen or Air