Hypoxic challenge test

When an aeroplane flies high up in the sky, the air outside becomes very, very thin. There isn’t enough air up there for people to breathe comfortably. To address this, aeroplane cabins are pressurized to mimic lower elevations – air is pumped into the cabin to create a safe and comfortable environment.

However, the partial pressure of the oxygen inside the aircraft is lower than what we breathe at sea level. As a result of the lower oxygen levels in the aircraft cabin, most passengers will experience a small decrease in oxygen saturation – the amount of oxygen circulating in the body.

Most people tolerate this well, however people with cardiac and respiratory problems however, may require additional oxygen for the flight.

The hypoxic challenge test will help evaluate how well your child will tolerate the reduced oxygen levels in the aeroplane.

The hypoxic challenge test takes place in a large cabin that simulates being in an aircraft. Your child will sit inside the cabin for around 20 minutes - this may be longer if your child requires additional monitoring.

We will attach a pulse oximeter to their finger or toe to monitor their oxygen saturation levels. The oximeter sensor uses a painless wrap which uses light to measure oxygen levels.

If needed, a nasal cannula (a thin plastic tube that wraps around the head) will be attached at the beginning of the test, to provide oxygen during the test.

Your child is welcome to take toys, books or a phone or tablet, inside the cabin to keep them entertained throughout the test. The department has iPads available to borrow if needed.

If needed, parents can sit inside the cabin with younger children but will need to wear a pulse oximetry probe too. Whilst inside the cabin babies can be bottle-fed or breast-fed if needed.

Some children who already have medical devices for example non-invasive ventilators (BPAP machine) may have a modified hypoxic challenge test. During the modified test your child will also be monitored whilst wearing their medical device. For these tests we will ask you to bring the device with you to the appointment.

The report will then be uploaded onto your child’s electronic patient record system for the doctor to view.

The appointment takes approximately 60 minutes but some tests may require longer if additional monitoring is needed.

Any medical equipment that your child requires for example suction equipment. Please bring along a favourite toy, book or electronic game which can help as a distraction during the test.

It can get hot inside the cabin, so you may wish to wear light clothing.

Please note, the person accompanying your child for the test should have ‘Parental Responsibility’ for them. Parental Responsibility refers to the individual who has legal rights, responsibilities, duties, power and authority to make decisions for a child. If the person bringing your child does not have Parental Responsibility, we may have to cancel the test.