Sleep Apnoea

What is Obstructive Sleep Apnoea?

Obstructive Sleep Apnoea is a reduction in normal breathing whilst sleeping. When the airflow is decreased by 90% for at least 10 seconds, this is called ‘apnoea’; an airflow reduction of between 50-90% for 10 seconds that leads to oxygen levels decreasing by 4% is called ‘hypopnoea’ (1). Obstructive Sleep Apnoea is characterised by periods of apnoeas and hypopneoas throughout the night. This causes people to wake up during the night, and so disturbing their sleep.

How common is Obstructive Sleep Apnoea?

Obstructive Sleep Apnoea is thought to occur in 2-4% of the middle aged population (2). It is twice as common in men than in women (3).

What causes Obstructive Sleep Apnoea?

Obstructive Sleep Apnoea is caused by obstruction of the upper airway near the back of the tongue. This occurs when the muscles of the neck relax during sleep. It is strongly linked to people who are overweight. In fact, 40% of those with a BMI of over 40 have been shown to have obstructive sleep apnoea. A large neck circumference (greater than 43cm) will also make someone more likely to suffer from Obstructive Sleep Apnoea. It is also thought that this condition can be associated in people with a strong family history, especially if both parents suffer from this.

Other causes can include alcohol and sleeping tablets as they relax the muscles of the upper airway as well.

What are the symptoms of Obstructive Sleep Apnoea?

Obstructive Sleep Apnoea can give many symptoms which can include:

• Excessive daytime sleepiness
• Headache
• Impaired memory
• Decreased concentration
• Decreased sex drive
• Irritability
• Going to the toilet at night
• Heavy snoring
• Periods of no breathing during sleep (often reported by the partner)

These symptoms occur as sleep is often disturbed.

How is Obstructive Sleep Apnoea diagnosed?

Obstructive Sleep Apnoea can be diagnosed by polysomnography, which is an overnight sleep study. This measures nasal/oral airflow; chest and abdomen movement; snoring; brain electrical activity (EEG); electrical activity of the eye movement (electrooculogram); muscle movement (electromyogram); electrical reading of the heart (ECG); oxygen levels.

An alternative to this may include ‘cardiorespiratory monitoring’ which only measures oxygen levels, airflow, respiratory effort and ECG.

Another way of measuring the severity of Obstructive Sleep Apnoea is to determine the number of apnoeas and/or hypopnoeas per hour. This is often called the apnoea/hypopnoea index (AHI) or respiratory disturbance index (RPI).

• AHI of 5-14 = mild;
• AHI 15-30/hr = moderate
• AHI >30/hr = severe.

Questionnaires may also be used to help assess how the person and their partner feel with regards to their sleepiness. This helps give the doctor and the patient an idea of how their sleepiness is perceived and for later on to see if treatment is working. Although there are many questionnaires, the most commonly used one in the UK is the Epworth Sleepiness Scale. This is a score marked out of 24 and the patient gives marks for each question. These questions are ‘how likely is it that you would fall asleep while you are….’:

1. Sitting and reading?
2. Watching TV?
3. Sitting inactive in a public place (eg a theatre or a meeting)?
4. As a passenger in a car for an hour without a break?
5. Lying down to rest in the afternoon when circumstances permit?
6. Sitting and talking to someone?
7. Sitting quietly after a lunch without alcohol?
8. In a car, while stopped for a few minutes in traffic?

Each question is answered either never (0 marks), slight chance (1 mark), moderate chance (2marks), or high chance (3 marks). These marks are then added up.

• <11 = normal
• 11-14 = mild
• 14-18 = moderate
• >18 = severe

What are the complications of Obstructive Sleep Apnoea?

Obstructive Sleep Apnoea can lead to several other conditions. One of these is high blood pressure, where 30-60% of patients suffer from this. It may also lead to an increased risk of heart disease such as angina, heart attacks and heart failure. Furthermore, there is an increased risk of stroke in people with Obstructive Sleep Apnoea.

How is Obstructive Sleep Apnoea treated?

Obstructive Sleep Apnoea can be treated in 3 main ways:

Non Medical

People suffering from Obstructive Sleep Apnoea are advised to

1. Lose weight
2. Stop smoking
3. Reduce and preferably not drink alcohol at nights
4. Avoid sedatives and sleeping tablets

Medical

The use of a machine called CPAP (Continuous Positive Airway Pressure) is the main medical treatment for Obstructive Sleep Apnoea. What this machine does is it continually blows air into your. This continual supply of air helps keep the airways open and prevents it from collapsing as it might normally do. By keeping the airways open, the lungs become better ventilated and this reduces the symptoms and potential complications as described above. Air is delivered overnight through a tight fitting mask.

However, there are some side-effects which the patient needs to be aware of. These can include a sor3e nose where the mask is fitted, rhinitis, a feeling of bloating and the machine can be considered noisy. Rarer side-effects include nose bleeds.

Another medical way of treating Obstructive Sleep Apnoea includes using devices you can place in your mouth. These devices work by moving the lower jaw forward, which makes the area around the throat larger. This therefore increases the amount of air that someone breathes in when they are asleep. Side-effects to using these devices can include increased saliva as well as teeth and gum problems. Other problems may occur, such as pain at the joint of the jaw and repeated dislodging of the device.

Unfortunately, there is no strong evidence that medication is able to help in Obstructive Sleep Apnoea.

Things to bear in mind

Because Obstructive Sleep Apnoea may cause excessive sleepiness during the day, it is advised that you should not drive if you feel sleepy. Remember that it is a criminal offence to fall asleep at the wheel. If you are diagnosed with Obstructive Sleep Apnoea, you must inform the DVLA – it is usually not a problem as long as you are under treatment for it. You should also explain this to your insurance company.

Key Points

1. Obstructive Sleep Apnoea is when breathing stops or is reduced for periods of time when asleep
2. It can cause people to be sleepy, irritable and have reduced concentration during the day
3. It can be treated with CPAP or oral devices, as well as changing one’s lifestyle

1. Kuhlmann U, Bormann FG, Becker HF. Obstructive sleep apnoea: clinical signs, diagnosis and treatment. Nephrol Dial Transplant. 2009 Jan;24(1):8-14.
2. Jennum P, Riha RL. Epidemiology of sleep apnoea/hypopnoea syndrome and sleep-disordered breathing. Eur Respir J. 2009 Apr;33(4):907-14.
3. Murugan AT, Sharma G. Obesity and respiratory diseases. Chron Respir Dis. 2008;5(4):233-42.