Sleep screen (trolley) study

Disclaimer: This fact sheet is for education purposes only. Please consult with your doctor or other health professional to make sure this information is right for your child.

PDF Versions Available

This fact sheet is available to print in the following languages:

What is a sleep screening (trolley) study?

A sleep screening (trolley) study is a simple test that helps identify any sleep problems that your child may have. Using sensors on your child’s skin, we measure the level of oxygen and carbon dioxide in the bloodstream. The study measures this while they sleep.

The results tell us if your child needs further testing (for example a full sleep study) or treatment.  The results can also be used to change the treatment your child is already receiving. Your child's doctor will discuss with you what they think should happen after the study.

What happens when you arrive at the hospital?

When you arrive at the hospital, ask the staff at the Enquires Desk for directions to the Sleep Unit. Please make sure you arrive at the Unit before 7pm, so we can prepare your child for the study.

The receptionist in the Sleep Unit will book your child in. You'll have to fill out some paperwork and then the receptionist will show you to the David Read Sleep Unit.

It's important that you stay in the Hospital with your child while they're in for the screening (trolley) study, otherwise we can't complete the study.

When you arrive, the Sleep Unit staff will explain what will happen and show your child the equipment to be used so that they are not frightened. This is also a good opportunity for you to ask any questions you or your child may have about the study.

We will provide dinner for your child. If your child is bottle fed or has a special diet, please ring the Sleep Unit on 9845 1150 by 9am on the day of your study and we will place a special order for them from the kitchen. There is a fridge and microwave in the parent room that you can use if you bring food for yourself from home. You can also buy dinner at the Hospital cafeteria which is open until 8pm (or 6.30pm on weekends and public holidays).

You and your child will each have a bed to sleep in overnight.

What next?

When your child goes to sleep, the Sleep Unit staff will put a sensor on your child's finger or toe to measure oxygen. They will also put a sensor onto the skin of their chest or stomach to measure carbon dioxide. The Sleep Unit staff will come into the room every hour to record the numbers on the machine. We try to do this quietly and gently to not disturb you or your child while you sleep.

We will monitor your child for at least 8 hours while they're sleeping. Around 5:30am or 6:00am, we'll gently wake your child and disconnect them from the sensors.

As we need to prepare the space for other patients, we do ask that you get up once we've removed the sensors. We will then take the equipment out of your room and look over the results. The doctor will also take blood from your child's arm in the morning. You are free to go home after this is done.

You need to make a follow-up appointment with your referring doctor or Sleep/Respiratory Doctor to discuss the results of the study.

What do you need to bring?

  • Medicare card with your child's name on it
  • Referral letter from your family doctor (GP)
  • Things that will help your child feel comfortable and go to sleep, e.g. pillows, toys or books
  • Button-up pyjamas (so we can put sensors on your child's skin)
  • Toiletries for you and your child - shower facilities are available
  • If your child is on CPAP or BiLevel therapy then you need to bring all equipment (e.g. CPAP/BiLevel machine, mask and tubing)
  • Medications your child uses or may need
  • Enough infant formula and bottles to last overnight
  • Your own pyjamas and a book, magazines etc.
  • Anything else you and your child may need overnight

Please note there's only enough space for one parent or carer to sleep by the child's bed.

If you have any questions before arriving, please call the Sleep Unit on 9845 1150


  • Please arrive before 7pm on the day of the study
  • You are free to go home after 6:30am the following morning
  • You need to stay at the Hospital while your child is having the study
  • You will get the study results from the doctor who asked for the test
  • You are responsible for arranging the follow-up appointment with your doctor
  • There is hospital parking available for $16. There is also some free parking available on the street. 
The Children's Hospital at Westmead

For publications recommended by our hospitals' experts, please visit the Kids Health book shop.