Definition Apnoea is defined as a pause in breathing that lasts 10 seconds or more. Obstructive sleep apnoea occurs when tissue in the upper airways blocks the breathing passages. The blockage may come from a collapsed uvula, which is the soft tissue that hangs down at the back of the palate, large tonsils, or other excess tissue. When the muscles relax during sleep, these structures can sink into the air passage and interrupt breathing. The person suffering from this condition continues to try to breathe during the periods when the airways are blocked. As a result of the disturbed breathing, too little oxygen gets into the bloodstream, a condition known as hypoxaemia. This problem corrects itself as soon as normal breathing is restored.
What is going on in the body? Sleep apnoea becomes a problem if breathing stops more than 20 times an hour. People with this condition often wake slightly to restore their breathing. These episodes disrupt normal sleep, which can result in extreme daytime sleepiness. Other traits of obstructive sleep apnoea include loud snoring and laboured breathing during apnoeas.
The typical person with this problem is a moderately overweight middle-aged man. The person sleeps fitfully and feels poorly rested in the morning. Snoring starts shortly after going to bed. A person sharing the same bed may notice fits of sleep apnoea. Because the individual is not sleeping well, drowsiness may interfere with normal daytime activities. Some people with this condition report falling asleep while driving or at work.
What are the signs and symptoms of the condition? Symptoms of obstructive sleep apnoea include:
loud snoring.
observed apnoea while sleeping.
morning headache. This may indicate elevated carbon dioxide due to apnoea.
restless sleep with many awakenings.
daytime drowsiness with episodes of sleeping spontaneously.
What are the causes and risks of the condition? Risk factors for obstructive sleep apnoea include:
obesity. Seventy percent (70%) of individuals with this problem are overweight. Symptoms often improve or go away entirely if some of this excess weight is lost.
neck size greater than 42 cm.
use of sedatives such as alcohol and tranquilisers.
narrowed upper airway. This may be from enlarged tonsils
.
being male. Obstructive sleep apnoea is occurs 3 to 20 times more often in men than in women. The women who do get it are most often past menopause.
tobacco smoking.
other lung diseases, such as destruction of the air sacs in the lung, or emphysema.
What can be done to prevent the condition? Treatment and prevention are very similar. Steps include losing weight and avoiding sedatives. It may be helpful for people with narrow breathing passages to have their tonsils and adenoids removed.
How is the condition diagnosed? If a person exhibits symptoms of obstructive sleep apnoea, a sleep study, called a polysomnogram, may be recommended. This study measures muscle strength of the diaphragm, which is the breathing muscle between the chest and the belly, and straining of the thorax, the wall of the chest. It assesses the strength of the breathing attempt, the ability to absorb oxygen into the blood, called oxygenation, and oesophageal reflux, which is the pushing of the stomach contents back up in to the oesophagus. It also monitors seizure activity and the collapse of airways. Oxygen saturation is measured, as well. An arterial blood gas test may also be performed to check levels of carbon dioxide and oxygen.
What are the long-term effects of the condition? People with this problem are prone to developing serious health conditions. One of these is excessively high blood pressure in the vessels of the lungs, called pulmonary hypertension, which results from a chronic lack of oxygen in the blood. Another serious complication is the abnormal enlargement of the right pumping chamber of the heart, known as right ventricular hypertrophy. If the problem is not treated, the heart can become so weakened that it cannot pump blood through the lungs, a condition called cor pulmonale.
Rarely, death can occur from sleep apnoea. When this happens it most likely the result of irregular heart rhythm, or cardiac arrhythmia, stroke, or heart attack. The death rate is higher among people who do not get treatment for the condition. Lack of treatment also raises a person's risk of high blood pressure. Correcting the sleep apnoea may help a person keep blood pressure under control.
Sleep deprivation is also a long-term effect. This leads to poor productivity and the inability to concentrate. It also increases the tendency to have accidents.
What are the risks to others? People with this problem run the risk of harming themselves and others in car or workplace accidents.
What are the treatments for the condition? There are a number of treatments for obstructive sleep apnoea. These are aimed at reducing airway blockage and increasing the amount of oxygen that gets into the blood. The first step is often a serious attempt at losing weight. Weight loss can reduce the number of apnoeas and may resolve the problem completely. It is also crucial to avoid sedatives, such as alcohol and tranquilisers or benzodiazapines.
If these measures do not help, the person may try something called continuous positive airway pressure, or CPAP. This involves wearing a mask over the nostrils and/or mouth that pumps in pressurised air. This process increases the amount of oxygen entering the lungs and relieves the symptoms of obstruction. The technique can be used with or without supplemental oxygen.
Another treatment involves surgery to remove excess tissue in the airway. This may include trimming extra tissue from the uvula as well as removing the tonsils and adenoids. If all other methods fail, it may be necessary to cut a small hole in the neck through which the person can breathe, called a tracheotomy, or administer supplemental oxygen. The purpose of this surgery is to bypass blockages in the upper airways.
What are the side effects of the treatments? If the person responds well to treatment, there are no side effects. The individual will sleep better and symptoms of daytime drowsiness and poor concentration disappear. However, if a person is not careful with diet and exercise, he or she may regain excess weight and symptoms will return once again.
What happens after treatment for the condition? Repeat sleep studies are often performed after surgery or treatment with CPAP.
How is the condition monitored? People will check in with their doctor periodically to report on the progress of their symptoms. For patients using CPAP and oxygen therapy, the doctor will stress the importance of sticking with the treatment.
Author: Jorge Allende, MD Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
