Equipment
There are two parts to the pulse oximeter, which are joined together:
- A rubber or plastic fingertip sensor
- A data storage device that fastens around your wrist with a Velcro or plastic strap and is slightly larger than a wristwatch.
Home or in a sleep centre?
The device is usually worn at home, but is so versatile it can be worn anywhere!
Who attaches the equipment?
You will usually be asked to attach the equipment.
How long does it take?
- 10 to 20 minutes at the sleep centre to collect the equipment (with instructions for use)
- Five minutes for attaching the equipment before bed
- At least four hours of sleep (preferably all night)
- Two minutes for removing the equipment in the morning
- Time to return the equipment to the sleep centre.
What is monitored?
Amount of oxygen in the blood / pulse rate
A plastic or rubber finger sensor is worn to check whether you have sleep apnoea. After each pause in breathing, the level of oxygen in your body dips and your pulse rate rises before returning to normal. If this happens repeatedly, sleep apnoea can be diagnosed.
Results
The overnight reading is saved and memorised by the pulse oximeter while you sleep. It is downloaded the following day to give a reading in the form of graphs.
The graphs are viewed and interpreted so that a sleep specialist can form a diagnosis. You will be given an appointment with the specialist to receive your results.
Limitations of overnight oximetry
Pulse oximetry can show sleep apnoea very clearly. Unfortunately it cannot always distinguish between obstructive, central and mixed sleep apnoea. Your risk factors and symptoms must be taken into consideration when making a diagnosis.
If you show more unusual sleep behaviours or problems, you should be offered semi- or full polysomnography to gain a fuller picture of your condition.
