At risk babies should have an overnight saturation run prior to discharge.

Oxygen Saturation Targets

The targets above are for infants with chronic neonatal lung disease based on the available literature and guidelines. The median baseline saturation in healthy term infants during the first year of life is 97-98% however there is no evidence of benefit targeting these normal levels with oxygen therapy.

Infants who do not meet these minimum targets while breathing air but are otherwise ready for discharge should be considered for home oxygen therapy.

Before referral for home oxygen

Infants suitable for home oxygen therapy will:

• be clinically stable or improving – no significant cyanotic or apnoeic episodes in the preceding two weeks
• have no other significant cardio-respiratory co-morbidity contributing to their oxygen requirement
• demonstrate appropriate weight gain on current management
• meet the oxygen targets above at flows of ≤0.5 L/min nasal cannula oxygen
• have competent caregivers and appropriate home environment
• have undergone multi-disciplinary discharge planning including discussion of oxygen therapy goals, safety issues (smoking, open fires, etc), and implications for flying.

The Starship Paediatric Respiratory Service recommends a higher target (≥95%) in the context of pulmonary hypertension and infants should have clinical and ECG screening for this prior to discharge.

A relevant (generally recent) chest x-ray and capillary blood gas are useful investigations prior to discharge. Hypercarbia is associated with increased risk of hospital readmission3.

An ‘air challenge’, whereby the effects and safety of short-term oxygen disconnection is assessed is advisable. There is no evidence based protocol for this however the British Thoracic Society suggest a minimum SpO2 of ≥ 80% is maintained for 30 minutes off oxygen before discharge².

Referral to the Respiratory Service

Referral to the Starship Respiratory Service for formal review should be considered in any of the following contexts:

• There is severe clinical disease (work of breathing, x-ray changes, etc), instability or poor progress (eg poor weight gain).
• The oxygen requirement is > 0.25 L/min.
• The infant has a significant cardiovascular co-morbidity.
• Chronic neonatal lung disease is not the principle or only cause of respiratory failure (eg meconium aspiration).
• Oxygen therapy is anticipated for more than six months.
• The CO2 ≥ 7.9 kPa during or just after sleep.
• Sleep disordered breathing or aspiration are concerns.

It is more appropriate to refer these babies to Paediatric Homecare from the outset rather than Neonatal Homecare.

Request for home oxygen

• Referral to the ADHB home oxygen service for infants living in the ADHB and WDHB catchment areas is on the Paediatric Home Oxygen Request Form (CR2652).
• The minimum flow rate is 0.125 L/min.
• Approval from the Oncall or a Consulting Paediatric Respiratory Specialist is required (usually this is straightforward if the infant doesn’t have the features above).
• It is important that the name of the infant’s primary clinician whom will be supervising the oxygen therapy is indicated on the form.
• The approved referral must be faxed at least 3 week-days (72hr) prior to the day of discharge.
• All infants discharged on home oxygen require homecare team support until the oxygen is returned. This may involve transfer to Paediatric homecare as well as a General Paediatric Consultant as Neonatal Homecare involvement is only for the first 3 months

Follow up, weaning and discontinuation of home oxygen

• Infants on home oxygen will have regular review by the Homecare Nurses and by their primary clinician. It is generally the primary clinician’s role to make decisions about the weaning of oxygen, usually on the basis of the infant’s overall progress together with the results of oximetry studies.
• Oxygen flow rates are weaned as the infant improves such that the minimum oxygen targets above are always maintained.
• Oxygen requirements are highest during crying, feeding, bathing and sleep. For this reason oxygen is usually delivered continuously. Infants on 0.125 L/min may cope without oxygen during periods of quiet wakelfulness. If this is recommended it should be assessed by the Homecare nurses.
• Infants will typically have overnight oximetry studies every 2-6 weeks. The first oximetry should take place within 2 weeks of discharge and infants discharged on oxygen should be reviewed by Homecare the day after discharge. Guidelines for the performance and reporting of overnight oximetry studies are available on the Starship Clinical Guidelines site.
• Infants in whom the oximetry is well above targeted levels may be considered for weaning. Alternatively, where the oximetry is unsatisfactory, sometimes oxygen flow rates may need to be increased.
• Where a change is made to the flow rate (either up or down) this should be immediately reviewed with an oximetry study. Oxygen should not be weaned to a lower level until the oximetry on this level has been reviewed and reported.
• Infants should be reviewed by phone and/or visit by Homecare nurses following changes to flow rates.
• Oxygen may be discontinued when infants maintain target saturations in air. Where this is the case, oximetry should be repeated a week later as some infants may fatigue.
• Any changes, including discontinuation of oxygen must be notified to the ADHB Oxygen Service as it may have implications for oxygen supply (form CR 4521).
• Usually oxygen supply is left in the home for 3 months after discontinuation as many infants go back on oxygen during mild respiratory illnesses. This is particularly an issue over winter. Homecare should remain involved until the oxygen equipment is completely removed and both the primary clinician and Homecare nurses should be involved in decisions to re-start or re-stop oxygen.

Flying - when on oxygen and after oxygen has been discontinued.

The oxygen content inside aeroplanes flying at altitude is significantly less than at sea level (~15% vs 21% oxygen). This is not an issue for most healthy children but children on oxygen therapy will likely need more oxygen and those who have recently discontinued their oxygen may need to go back on it for the flight.

The rules, provisions and costs vary between airlines and it is worth shopping around. It is important to advise the airline well ahead of time. Generally flows of 2-4 l/min are available, usually much higher than the infant is usually on or strictly will need.

In infants where the need or prescription for in flight oxygen is unclear, the Respiratory Physiology Laboratory at Starship Childrens can do a test where cabin air conditions are simulated (15% oxygen) while oximetry is measured and oxygen (if needed) titrated. The British Thoracic Society recommends this test for infants flying within six months of discontinuing oxygen therapy.

References