Patient information on Obstructive Sleep Apnoea (OSA) – Part I
Who is this information for?
This information is for patients, families and carers of patients with Obstructive Sleep Apnoea.
What is OSA?
- Normally during sleep, air moves through the throat and in and out of the lungs at a regular
- In a person with sleep apnea, air movement is periodically diminished or stopped.
- There are two types of sleep apnea:
- obstructive sleep apnea: breathing is abnormal because of narrowing or closure of the
- central sleep apnea: breathing is abnormal because of a change in the breathing
control and rhythm.
- Sleep apnea is a serious condition that can affect a person’s ability to safely perform normal
daily activities and can affect long-term health.
- Approximately 25 percent of adults are at risk for sleep apnea of some degree.
- Men are more commonly affected than women.
- Other risk factors include:
What causes OSA?
- The throat is surrounded by muscles that
control the airway for speaking, swallowing,
- During sleep, these muscles are less active,
and this causes the throat to narrow, SEE
- In most people, this narrowing does not
affect breathing. In others, it can cause
snoring, sometimes with reduced or
completely blocked airflow, SEE FIG.
- A completely blocked airway without
airflow is called an obstructive apnea.
- Partial obstruction with diminished airflowis called a hypopnea.
- A person may have apnea and hypopnea during sleep.
- Insufficient breathing due to apnea or hypopnea causes oxygen levels to fall and carbon dioxide
- Typically, the obstruction requires the person to awaken to activate the upper airway muscles.
- Once the airway is opened, the person then takes several deep breaths to catch up on
- As the person awakens, he or she may move briefly, snort or snore, and take a deep breath.
- Less frequently, a person may awaken completely with a sensation of gasping, smothering, or
- If the person falls back to sleep quickly, he or she will not remember the event.
- Many people with sleep apnea are unaware of their abnormal breathing in sleep, and all
patients underestimate how often their sleep is interrupted.
- Awakening from sleep causes sleep to be un-refreshing and causes fatigue and daytime
Specific Causes of obstructive sleep apnea
- Most patients have OSA because of a small upper airway.
- As the bones of the face and skull develop, some people develop a small lower face, a
small mouth, and a tongue that seems too large for the mouth. These features are
genetically determined, which explains why OSA tends to cluster in families.
- Obesity is another major factor.
- Tonsil & Adenoid enlargement can be an important cause, especially in children.
Symptoms of OSA
- The main symptoms of OSA are loud snoring, fatigue, & daytime sleepiness.
- However, some people have no symptoms. For example, if the person does not have a
bed partner, he or she may not be aware of the snoring. Fatigue and sleepiness have
many causes and are often attributed to overwork and increasing age. As a result, a
person may be slow to recognize that they have a problem. A bed partner or spouse
often prompts the patient to seek medical care.
- Other symptoms may include one or more of the following:
- Restless sleep
- Awakening with choking, gasping, or smothering
- Morning headaches, dry mouth, or sore throat
- Waking frequently to urinate
- Awakening unrested, groggy
- Low energy, difficulty concentrating, memory impairment
Risk factors for OSA
- Certain factors increase the risk of sleep apnea.
- Increasing age: OSA occurs at all ages, but it is more common in middle and older age adults.
- Male gender: OSA is two times more common in men, especially in middle age.
- Obesity. The more obese a person is, the more likely they are to have OSA
- Sedation from medication or alcohol interferes with the ability to awaken from sleep and can
lengthen periods of apnea (no breathing), with potentially dangerous consequences.
- Abnormality of the airway.
Complications of OSA
- Complications of sleep apnea can include daytime sleepiness and difficulty concentrating.
- The consequence of this is an increased risk of accidents and errors in daily activities.
- Studies have shown that people with severe OSA are more than twice as likely to be
involved in a motor vehicle accident as people without these conditions.
- People with OSA are encouraged to discuss options for driving, working, and
performing other high-risk tasks with a healthcare provider.
- People with untreated OSA may have an increased risk of cardiovascular problems such as
high blood pressure, heart attack, abnormal heart rhythms, or stroke.
- This risk may be due to changes in the heart rate and blood pressure that occur during
How is OSA diagnosed?
- The diagnosis is usually based upon the person’s medical history, physical examination, and
- Testing is usually performed in a sleep laboratory.
- A full sleep study is called a polysomnogram (PSG).
- The PSG measures the breathing effort and airflow, blood oxygen level, heart rate and
rhythm, duration of the various stages of sleep, body position, and movement of the
- Home monitoring devices are available that can perform a modified sleep study.
- This is a reasonable alternative to conventional testing in a sleep laboratory if the
clinician strongly suspects moderate or severe sleep apnea and the patient does not
have other illnesses or sleep disorders that may interfere with the results.