An oximetry test measures the amount of oxygen in the blood. It's a simple and painless test.
An oximetry is a test done by a machine called a pulse oximeter. A sensor is placed onto your child's finger, toe or ear lobe. The sensor uses light to measure the amount of oxygen in your child's blood, as well as their heart rate. It does not hurt and is very simple to put on and use.
Oximetry can be used to measure the amount of oxygen in your child's blood in either of these ways:
Spot oximetry can be used to check for low oxygen levels (hypoxia) in newborn babies to help identify those who may have been born with heart problems. It only takes a few minutes. The neonatal doctor (a doctor who looks after newborn babies) will give you more information.
Continuous pulse oximetry over a period of hours or days can be used in hospital when a child is sick. It can help guide decisions about whether your child needs oxygen therapy. Sometimes when a child needs to use respiratory equipment at night for their breathing, continuous oximetry is used to make sure the treatment is working properly.
Overnight pulse oximetry can be done in hospital or at home to measure oxygen levels when a child is asleep. It can be used in the following ways.
Disordered breathing during sleep can be due to:
Your doctor arranges an overnight oximetry test through your local hospital. Usually, a technologist or nurse will set up the oximeter in the hospital so that the settings and alarms are right for your child. They will give you instructions for using the machine, including how to place and fix the sensor for best results. You usually borrow the machine overnight and return it to the hospital the next day.
Before the oximetry test, you can help prepare your child by explaining what is going to happen and reassuring them. If your child is having oximetry to find out if they have sleep disordered breathing, there may be a short sleep questionnaire to complete. It will really help your doctor to have a summary of your child's symptoms (for example, snoring, noisy breathing, pauses in breathing, daytime sleepiness and behaviour problems).
During the overnight oximetry, it can also be really helpful if you keep a note of any important events that take place while the oximeter is recording and what time they happened. Examples are being awake, crying, being asleep, feeding, noisy breathing or snoring, problems with equipment, alarms. It's also a good idea to record whether you felt your child's sleep was typical of a normal night's sleep for them. The doctors need to have as much of your child's overnight sleep recorded as possible on the oximeter, or at least 6 hours of recording.
There is little risk involved. Very occasionally, a child's skin may react to the tapes or sensors resulting in a short-term rash. Oximetry itself is painless but may be distracting or annoying for some children because of the red light from the sensor. Staff will tell you how to hide the sensor, if on a foot, by putting a sock over the top.
Having a normal oxygen level does not mean that your child does not have sleep disordered breathing. It also doesn't mean that they won't need further tests or treatments.
When you return the oximeter to the hospital, the doctor will analyse the data or information from the machine and send a report to the doctor who arranged the oximetry test. If the recording time is less than 6 hours, your child may need to do another oximetry test.
When oximetry testing is used to help find out if there is snoring or noisy breathing, it's important to remember that having a normal oxygen level does not mean that your child does not have sleep disordered breathing. It also doesn’t mean that they won't need further tests or treatments. The doctor who arranged the overnight oximetry is responsible for letting you know the results of the study and working with you and your child if any further follow-up tests or treatments are necessary.
Paediatric Sleep Medicine Clinical Network. Paediatric Society New Zealand. 2014. Revised 2015.Guidelines for the assessment of sleep-disordered breathing in children. https://www.starship.org.nz/guidelines/sleep-and-sleep-disordered-breathing-in-children [2] [Accessed 16/07/2020]
Starship Clinical Guidelines. 2009. Revised 2018. Oximetry.https://www.starship.org.nz/guidelines/oximetry/ [3] [Accessed 16/07/2020]
Australian Sleep Association. Overnight Oximetry for evaluating paediatric obstructive sleep apnoea. 2004. https://sleep.org.au/common/Uploaded%20files/Public%20Files/Professional%20resources/Sleep%20Documents/ASA%20Paed%20Oximetry%20Technical%20Guideline%20Approved%20Mar%202019.pdf [4] [Accessed 31/01/2020]
The content on this page has been developed and approved by the Paediatric Sleep Medicine Clinical Network, Paediatric Society New Zealand.
This page last reviewed 05 December 2019.
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Links
[1] https://www.kidshealth.org.nz/snoring-noisy-breathing
[2] https://www.starship.org.nz/guidelines/sleep-and-sleep-disordered-breathing-in-children
[3] https://www.starship.org.nz/guidelines/oximetry/
[4] https://sleep.org.au/common/Uploaded%20files/Public%20Files/Professional%20resources/Sleep%20Documents/ASA%20Paed%20Oximetry%20Technical%20Guideline%20Approved%20Mar%202019.pdf
[5] https://www.kidshealth.org.nz/contact?from=http%3A%2F%2Fwww.kidshealth.org.nz%2Fprint%2F2125%3Flanguage%3Dton