What is Sleep Apnoea?

Sleep apnoea is a very serious breathing disorder, which can be life threatening. Sleep apnoea is characterised by your breathing stopping for brief intervals of time while you are asleep. There are two types, central sleep apnoea and obstructive sleep apnoea.
Central sleep apnoea is uncommon. This happens when the brain fails to send messages to the muscles in the respiratory system to initiate breathing.
Obstructive sleep apnoea is more common and results from a blockage of upper airways during sleep.

What are the risk factors?

Sleep apnoea may occur in all age groups and in both sexes. It is more likely to affect people who:

• Are overweight and snore loudly,
• Have high blood pressure,
• Have some structural abnormality in the nose, throat, or other parts of the upper airway.

It may also have a genetic basis as it tends to run in some families.

What are the causes of Sleep Apnoea?

In most people, apnoea happens when the throat muscles and tongue relax during sleep, which then falls back and partially blocks the opening of the airways. Then the uvula (the small fleshy tissue hanging from the centre of the back of your mouth) and soft palate also collapses backwards. This completely blocks the upper airway.

The breathing movements of the diaphragm, the chest and the abdomen may further aggravate the blockage. When this happens your breathing becomes laboured and noisy and it may even stop. This wakes you up, causing tension to return to the tongue muscles, opening the airway and thus the normal breathing resumes.

If you are overweight, excess tissue in the breathing passage may narrow it and cause a slight obstruction in the free airflow in and out of nose and mouth. This may make you snore loudly and you may have frequent episodes of suddenly stopping breathing while you are asleep, which will in turn wake you up.
If you consume alcohol frequently or take sleeping pills, the duration and frequency of sleep apnoea may increase, as you will not waken as easily.
 

How is normal breathing resumed?

When your breathing stops, the oxygen levels in your blood begin to drop and carbon dioxide levels to rise. This drop in oxygen saturation makes your heart beat faster. In addition to this, a high concentration of carbon dioxide in the blood will alarm your brain, which in turn will then send signals to resume breathing. This process will wake you up so you can consciously clear the upper airway blockage. Breathing is resumed, often with a loud snort or gasp.

What are the effects of Sleep Apnoea?

Frequent apnoeic spells do not allow you to have a continuous, deep, restorative sleep. You may feel very sleepy during the daytime. This may be associated with early morning headaches. You may not be able to concentrate and this may also affect your performance. You may fall asleep during work. Other effects may include weight gain, depression, forgetfulness, irritability, sexual dysfunction, and learning or memory problems. You may also have high blood pressure. It also increases the risk for heart attack and stroke.

How is it diagnosed?

If you suffer from sleep apnoea, it is usually first suspected by your spouse who may become aware of your heavy snoring and your struggle to breathe. In work your colleagues may notice that you fall asleep during the day. You yourself may be quite unaware of the problem and may not believe them when they tell you.
However in such situations you should consult your doctor. He will thoroughly examine your upper airway and may refer you for a sleep test called a Polysomnography. This test helps in both diagnosing the condition as well as assessing the severity of the condition. It records various body functions during sleep, such as the electrical activity of the brain, eye movement, chin movement, heart rate, chest and abdominal effort, air flow, snoring, leg movement and blood oxygen levels.

What is the treatment?

Your doctor may suggest treatment based on your medical history, physical examination, and the results of Polysomnography. Generally medication is not used in the treatment of sleep apnoea.
Various approaches to treat the condition include:

Lifestyle adjustment: Your GP may advise that you change some things within your lifestyle that may help to prevent the sleep apnoea. If you are obese, losing weight may reduce the number of apnoeic events. Quitting smoking and cutting down alcohol consumption may also help. You should also avoid the use of sleeping pills. Sleeping on your back may cause sleep apnoea. If this may be the case, you should start sleeping on your side.

Physical or Mechanical Therapy: If you have central sleep apnoea (which is rare), oxygen administration may benefit you but it is not used to treat obstructive sleep apnoea.
The most effective and commonly used treatment for sleep apnoea is Nasal continuous positive airway pressure (CPAP). In this, you wear a mask over the nose during sleep. This mask is connected to an air blower that blows air at certain pressure into the upper airways. The air pressure is adjusted to prevent the throat from collapsing during sleep. This pressure is constant and continuous and acts as a splint holding your airways open.

Nasal CPAP effectively prevents sleep apnoea while in use, but apnoeic episodes return when its use is stopped.
Repositioning of the lower jaw and the tongue by dental appliances may also help in mild sleep apnoea. However possible side effects are damage to teeth, damage to soft tissues, and damage to the jaw joint.

Surgery: Surgery may be used to increase the size of the airways. Commonly used procedures include removal of adenoids and tonsils (especially in children), any excessive tissue in the airway, nasal growths, and the correction of structural deformities. These procedures are more successful in young people.

Laser surgery may also be used to eradicate excess tissue in the back of the throat.
Very occasionally for life-threatening sleep apnoea, a procedure called Tracheostomy is done (in which a small hole is made in the windpipe and a tube is inserted into the opening). It is kept closed during waking hours, and enables the person to breathe and speak normally. When the person sleeps, it is opened so the air goes straight into the lungs, bypassing any upper airway obstruction.


Written by Medpages Editorial Team
Last Editorial Review: 15/1/2010