Obstructive Sleep Apnoea

obstructive sleep apnoea

Obstructive sleep apnoea (OSA) is a condition where your breathing stops for short spells when you are asleep. In the case of OSA, the breathing stops because of an obstruction to the flow of air down your airway. The obstruction to the airflow occurs in the throat at the top of the airway. You may also have episodes where your breathing becomes abnormally slow and shallow. This is called hypopnoea.

What happens in people with obstructive sleep apnoea?

When we sleep, the throat muscles relax and become floppy (like other muscles). In most people, this does not affect breathing. If you have OSA, the throat muscles become so relaxed and floppy during sleep that they cause a narrowing or even a complete blockage of the airway.
If there is a complete blockage then your breathing actually stops (apnoea) for around 10 seconds. Your blood oxygen level then goes down and this is detected by your brain. Your brain then tells you to wake up and you make an extra effort to breathe.
If someone watches you, he or she will notice that you stop breathing for a short time, and then make a loud snore and a snort, perhaps even sound as if you are briefly choking, briefly wake up, and then get straight back off to sleep.
For the diagnosis of OSA, you need to have at least five episodes of apnoea, hypopnoea, or both events per hour of sleep. However, there are different levels of severity of OSA (mild, moderate or severe).

  • Mild OSA - between 5-14 episodes an hour.
  • Moderate OSA - between 15-30 episodes an hour.
  • Severe OSA - more than 30 episodes an hour.

Daytime sleepiness in someone who is a loud snorer at night is the classic hallmark of someone who has OSA.
Who gets obstructive sleep apnoea?
It most commonly develops in middle-aged men who are overweight or obese. Factors that increase the risk of developing OSA, or can make it worse, include the following.

  • Overweight and obesity.
  • Drinking alcohol in the evening.
  • Enlarged tonsils.
  • Taking sedative drugs.
  • Sleeping on your back rather than on your side.
  • Having a small or receding lower jaw.
  • Smoking.
  • You may also have a family history of OSA.

What are the symptoms of obstructive sleep apnoea?

  • Daytime sleepiness.
  • Poor concentration and mental functioning during the day.
  • Not feeling refreshed on waking.
  • Morning headaches.
  • Depression.
  • Being irritable during the day.

How is obstructive sleep apnoea diagnosed?

Epworth Sleepiness Scale
If you have daytime tiredness, sometimes a questionnaire is used to measure where you are on the Epworth Sleepiness Scale.

Tests to confirm OSA

  • By using a probe placed under your nose, your airflow may be measured whilst you sleep .
  • A sensor may record snoring volume and body movement whilst you sleep.
  • The oxygen level in your blood can be monitored by a probe clipped on to your finger.
  • Breathing can be monitored and recorded by the use of special belts placed around the chest and abdomen.
  • A video of you sleeping may be helpful.
  • You may be asked to spend a night in hospital for the tests to be done..
  • You doctor will usually check your blood pressure. (OSA is associated with high blood pressure.)

What is the treatment for obstructive sleep apnoea?

  • Losing some weight if you are overweight or obese.
  • Not drinking alcohol for 4-6 hours before going to bed.
  • Not using sedative drugs.
  • Stopping smoking if you are a smoker.
  • Sleeping on your side or in a semi-propped position.
  • Continuous positive airway pressure (CPAP).
  • This is the most effective treatment for moderate or severe OSA. This treatment involves wearing a mask when you sleep. A quiet electrical pump is connected to the mask to pump room air into your nose at a slight pressure. The slightly increased air pressure keeps the throat open when you are breathing at night and so prevents the blockage of airflow.
    Lifelong treatment is needed.

Mandibular advancement devices

The mandible is the lower jaw. There are devices that you can wear inside your mouth when you sleep. They work by pulling the mandible forward a little so that your throat may not narrow as much in the night.


Surgery is not often used to treat OSA in adults. However, sometimes an operation may be helpful to increase the airflow into your airway. For example, if you have large tonsils or adenoids, it may help if these are removed.

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