Obstructive sleep apnoea

Obstructive sleep apnoea (OSA) is a fairly common condition. During sleep, the walls of your throat relax and narrow or close, and this interrupts your normal breathing. Your sleep can end up broken again and again, and that can:

• affect your quality of life, mainly by making you very sleepy during the day
• raise your risk of developing certain conditions

Obstructive sleep apnoea (OSA) causes two types of breathing interruption:

• apnoea, a total blockage of the airway for 10 seconds or more
• hypopnoea, a partial blockage of the airway that causes airflow to reduce by more than 50% for 10 seconds or more

People with OSA may have apnoea and hypopnoea throughout the night. In severe cases, episodes may happen around once every 1 or 2 minutes.

You may also hear OSA called obstructive sleep apnoea-hypopnoea syndrome (OSAHS). Here, a person has apnoeas and hypopnoeas through the night, and their quality of life suffers because of sleepiness during the day and other symptoms. OSA and OSAHS are the same thing.

Signs of obstructive sleep apnoea (OSA) can include:

• being very sleepy during the day
• breathing pauses through the night (a partner, friend or relative may notice this)
• loud snoring
• noisy and/or laboured breathing
• repeated periods where breathing stops or is interrupted by gasping or snorting

Some people with OSA may also have night sweats, and may wake up often during the night to pee.

During an episode, the lack of oxygen triggers your brain to pull you out of deep sleep, either into a lighter sleep or into wakefulness. Your airway then reopens and you can breathe normally. These repeated sleep interruptions can leave you very tired and more likely to fall asleep during the day. You'll usually have no memory of your interrupted breathing, so you may not know you have a problem.

• you think you might have obstructive sleep apnoea (OSA), especially if you're very sleepy during the day

The doctor can check for other possible reasons for your symptoms and may refer you to a sleep specialist.

Before you see your doctor, it may help to ask a partner, friend or relative to watch you while you're asleep, if that's possible. If you have obstructive sleep apnoea (OSA), they may be able to spot pauses in your breathing.

It may also help to fill out an Epworth Sleepiness Scale questionnaire. It asks how likely you are to doze off in different situations, for example watching TV, sitting in a meeting or while driving. The final score helps your doctor decide whether you may have a sleep disorder.

Your doctor will usually ask about your symptoms. They may also check your blood pressure and take a blood sample. This can help rule out other conditions that might explain your tiredness, such as an underactive thyroid gland (hypothyroidism) or anaemia.

The next step will usually be an assessment through the night (a sleep study). Your sleeping pattern is checked to see whether you have a high number of breathing pauses during the night. Having some pauses is common, but a high number is abnormal. Your doctor can refer you to specialist clinics or hospital departments that investigate and treat people with sleep disorders.

The sleep specialists at the sleep centre may ask about your symptoms and medical history, and they may examine you. They may measure your height and weight to work out your body mass index (BMI), and measure around your neck too. This is because being overweight and having a large neck can raise your risk of obstructive sleep apnoea (OSA).

Next, the specialists will arrange for your sleep to be assessed overnight. This can be done in one of two ways:

• you take some monitoring equipment home and bring it back the next day for them to analyse (this is common)
• you spend the night at the clinic (this is rare)

In many cases the sleep centre will teach you how to use portable recording equipment while you sleep at home.

The equipment you are given may include:

• a breathing sensor at your nose or mouth
• sensors to monitor your heart rate
• bands that are placed around your chest
• oxygen sensors that are put on your finger
• a small sensor that sticks on your chin

The equipment records your oxygen levels, breathing movements, heart rate, snoring and body sleeping position through the night.

If more information is needed, you may be asked to spend the night at the sleep centre. The main test used there to analyse your sleep is called polysomnography. During the night, several different parts of your body are carefully monitored while you sleep. Bands and small metallic discs called electrodes are placed on the surface of your skin and on different parts of your body. Sensors are also placed on your legs, and an oxygen sensor is attached to your finger.

Different tests are carried out during polysomnography, including:

• electroencephalography (EEG), which monitors brain waves
• electromyography (EMG), which monitors muscle tone
• recordings of movements in your chest and abdomen
• recordings of airflow through your mouth and nose
• pulse oximetry, which measures your heart rate and blood oxygen levels
• electrocardiography (ECG), which monitors your heart

Sound recording and video equipment may also be used.

If OSA is diagnosed early in the night, you may be given continuous positive airway pressure (CPAP) treatment. CPAP uses a mask that delivers constant compressed air to the airway and stops it closing, which prevents OSA.

Once the tests are finished, the staff at the sleep centre should have a good idea whether you have OSA. If you do, they can work out how much it is interrupting your sleep and recommend the right treatment.

How severe your obstructive sleep apnoea (OSA) is depends on how many times your breathing pauses in each hour of sleep. Doctors count these episodes using the apnoea-hypopnoea index, or AHI.

The levels of severity are:

• mild: an AHI reading of 5 to 14 episodes an hour
• moderate: an AHI reading of 15 to 30 episodes an hour
• severe: an AHI reading of more than 30 episodes an hour

Treatment is most likely to be beneficial if you have moderate or severe OSA. It's also most likely to help if you feel very sleepy during the day. However, treatment may help some people with mild OSA too.

There are treatments that can reduce the symptoms of obstructive sleep apnoea (OSA).

Some simple changes to your daily habits can ease the symptoms of obstructive sleep apnoea:

• losing weight
• stopping smoking
• cutting down on alcohol
• sleeping on your side
• avoiding sedative medicines and sleeping tablets

If you have moderate to severe obstructive sleep apnoea (OSA), you will usually need to use a continuous positive airway pressure (CPAP) device. It sends a steady flow of compressed air through a mask, and this stops your airway closing while you sleep.

CPAP can feel strange at first, and you may be tempted to give it up. But people who stick with it usually get used to it quite soon, and their symptoms improve a great deal.

Telemonitoring may be used to check how well CPAP is working for you. This means health professionals can see how much you are using your CPAP therapy. They can spot any problems they can help with, and they can make adjustments where needed.

CPAP reduces symptoms such as snoring and tiredness. In people who have symptoms, it can also lower the risk of complications of OSA, such as high blood pressure.

Possible side effects of using a CPAP device include:

• mask discomfort
• nasal congestion, runny nose or irritation
• difficulty breathing through your nose
• headaches and ear pain
• stomach pain and flatulence (wind)
• claustrophobia

A mandibular advancement device (MAD) is a dental appliance, a bit like a gum shield, that's sometimes used to treat mild obstructive sleep apnoea (OSA). It's not generally recommended for more severe OSA. But it may be an option if a CPAP device isn't right for you.

You wear a MAD over your teeth while you sleep. It holds your jaw and tongue forward, which increases the space at the back of your throat and reduces the narrowing of your airway that causes snoring.

You should have your MAD made for you by a dentist who has training and experience in treating sleep apnoea.

A MAD may not suit you if you have few teeth, or none at all. If you have dental caps, crowns or bridgework, speak to your dentist first, so they can make sure the device won't stress or damage them.

Surgery may be an option if obstructive sleep apnoea (OSA) is thought to come from a physical problem that an operation can correct. Enlarged tonsillar tissue is one example. For most people, though, surgery isn't appropriate. Doctors may consider it only as a last resort, when other treatments haven't helped.

Treatments can often help control the symptoms of obstructive sleep apnoea (OSA), but in most cases you'll need them for life.

If OSA is left untreated, it can cause problems such as poor performance at work and school, and it can strain your relationships.

Poorly controlled OSA may also raise your risk of:

• developing high blood pressure (hypertension)
• having a stroke or heart attack
• developing an irregular heartbeat, such as atrial fibrillation
• developing type 2 diabetes (although it's unclear if this is the result of an underlying cause, such as obesity)