OBSTRUCTIVE SLEEP APNOEA: Australian Lung Foundation selected Information sheets: NEVDGP

People who suffer from obstructive sleep apnoea (OSA) slow or stop breathing for short periods while sleeping. This can happen many times during the night. It results in poor sleep with excessive sleepiness during the day. Because these events occur during sleep, a person suffering from OSA is often the last one to know what is happening.

In deep sleep, the muscles of the throat relax. Normally this doesn't cause any problems with breathing. In OSA, however, complete relaxation of the throat muscles causes blockage of the upper airway at the back of the tongue. Normal breathing then slows or stops completely. Such an episode is called an apnoea. During an apnoea, people with OSA make constant efforts to breathe against their blocked airway until the blood oxygen level begins to fall. The brain then needs to arouse the person from deep relaxed sleep so that the muscle tone returns, the upper airway then opens and breathing begins again. Unfortunately, when a person with OSA falls back into deep sleep, the muscles again relax and the cycle repeats itself again and again overnight.

In OSA, the apnoeas can last for 10 or more seconds and the cycle of apnoeas and broken sleep is repeated hundreds of times per night in severe cases. Most sufferers are unaware of their disrupted sleep but awaken unrefreshed, feeling tired and in need of further refreshing sleep.

Whilst OSA is more common in overweight middle-aged males who snore, it can also affect females, although female hormones and a difference in throat structures may protect women until the menopause. Narrowing of the back of the throat and the upper airway can also contribute to the risk of getting OSA, even in people who are not overweight or middle-aged. In such people, a blocked nose, a small jaw, enlarged tongue, big tonsils, and uvula help to block the upper airway in deep sleep, making OSA more likely to occur. Several of these problems can be present in any person at the same time.

The use of alcohol, sleeping tablets and tranquillisers prior to sleep help to relax the upper airway muscles and make OSA worse. Alcohol can also reduce the brain's response to an apnoea which in turn leads to longer and more severe apnoeas in people who would otherwise only have mild OSA and who would otherwise only snore.

Most people with OSA snore loudly and breathing during sleep may be laboured and noisy. Sleeping partners may report multiple apnoeas lasting up to 90 seconds which often end in deep gasping and loud snorting. Sufferers may report waking for short periods after struggling for breath. Symptoms are often worse when lying on the back in deepest sleep.

What are the symptoms of OSA?

Although a person with OSA may not be aware of the many arousals from deep sleep, they suffer from poor quality sleep in spite of long periods of time spent in bed. Such people wake feeling that they haven't had a full refreshing night's sleep. They report difficulty maintaining concentration during the day, have a poor memory, and suffer from excessive daytime sleepiness.

At first an OSA sufferer may be sleepy only when seated and relaxed, eg watching TV, but eventually sleepiness becomes so severe that car accidents and accidents in the workplace occur.

Other symptoms of OSA include morning headache, depression, short temper, grumpiness, personality change, and loss of interest in sex with impotence in males.

What other problems can develop from OSA?

OSA can be life-threatening. It is a risk factor for high blood pressure, heart attack, heart failure, and stroke. All these conditions occur more frequently in people with OSA.

OSA associated poor concentration and daytime sleepiness have been associated with an increased risk of accidents in the workplace and on the road. Motorcar accidents have been shown to be 2 to 5 times more common in people with OSA than in other people.

How is OSA assessed?

In a person suspected of having OSA, their doctor will need to ask questions about waking and sleeping habits. Reports from the sleeping partner or household member about any apnoeas are extremely helpful.

Referral to a sleep disorders centre for an overnight sleep study is needed for the diagnosis of OSA to be made and its severity measured.

During a sleep study, sleep quality and breathing are measured by a computer overnight while the person sleeps. Small coin-sized electrodes are taped to special points on the scalp, face, chest and legs. Chest and stomach wall movements are also measured and a special sensor placed on the upper lip measures airflow. The oxygen level in the blood is assessed by a device placed on the finger or the ear-lobe. Nome of these procedures is uncomfortable so they don't interfere with sleep.

More than one overnight study may be needed. The first is to measure what is going on, and the second is to start off treatment if needed.

The chosen form of treatment depends on the severity of OSA.

General Guidelines

In an overweight person, weight loss is an important part of treatment. Even a small loss of weight can lead to improvement in symptoms of OSA.

Avoiding alcohol up to 2 hours before going to sleep and not using any sleeping tablets or tranquillisers can also be of help.

Nasal obstruction may respond to nasal decongestant sprays.

Because OSA can be positional in some cases, it may be helpful to avoid sleeping on the back. Positioning devices such as special pillows, rubber wedges and tennis balls attached to pyjama backs encourage sleeping on the side but are of limited value in very severe OSA.

Specific Treatments

Continuous positive airway pressure (CPAP): A CPAP pump is the commonest treatment for OSA and is very effective in many cases. A CPAP pump delivers air at low pressure to the upper airways via a plastic tube attached to a close-fitting nose mask. It is worn during sleep and acts by keeping the upper airway open during deep sleep with air delivered at a positive pressure. This form of treatment is ideal for moderate to severe OSA. It prevents disrupted sleep, improves sleep quality, reduces daytime sleepiness, and abolishes snoring.

The amount of CPAP pressure needed in each person with OSA usually requires a second overnight study in a sleep disorders centre. This study is needed to determine the correct setting for CPAP pressure. After the correct pressure has been determined, a CPAP machine can be purchased or rented. In some states there may be a subsidy for CPAP treatment, and some health insurance companies may assist with the cost of a machine.

Other non-surgical treatments: Other treatments have only limited value in the management of OSA. Devices worn in the mouth during sleep (Mandibular advancement splints) which attempt to move the jaw forward are being assessed but their role in adults remains unclear at present. Their use requires close cooperation between a sleep disorder specialist and an orthodontist before use of such a device can be recommended.

Surgery: Surgery to the upper airway may ease some of the physical problems that help to block the airway during sleep. These operations are of limited benefit to patients with severe OSA, and include:

What is it like using a CPAP machine?

Many people with OSA who begin treatment with CPAP report that they haven't slept so well for years. They state that they feel 'normal' again. Many are astounded at the improvement in their day-to-day lives.

At first the use of a CPAP mask produces an unusual sensation when breathing out. It feels as if there is too much pressure stopping breathing. This sensation soon wears off. During the first week, nasal stuffiness and sneezing may occur, especially in colder weather. It often improves with warming the bedroom at night or using a humidifier with the CPAP machine. Occasionally an air leak from the nasal mask can irritate the eyes and air leak through the mouth can cause a dry mouth. A chin strap may be needed to overcome this problem. Staff in sleep disorder centres throughout the country can assist when problems occur.

Please Note: This information is intended by The Australian Lung Foundation to be used as a guide only and is not an authoritative statement. Please consult your family doctor or specialist respiratory physician if you have further questions relating to the information provided here.

© 1996, The Australian Lung Foundation