Patient information on Obstructive Sleep Apnea (OSA) – Part I
Who is this information for?
This information is for patients, families and carers of patients with Obstructive Sleep Apnea.
What is OSA?
- Normally during sleep, air moves through the throat and in and out of the lungs at a regular rhythm.
- 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 throat.
- 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:
- middle and older age,
- being overweight or obese,
- having a small mouth and throat.
What causes OSA?
- The throat is surrounded by muscles that control the airway for speaking, swallowing,and breathing.
- During sleep, these muscles are less active,and this causes the throat to narrow, SEE FIG.
- 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 air flow is 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 to rise.
- 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 breathing.
- 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 choking.
- 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 sleepiness.
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 which can warrant Adenotonsillectomy.
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 abed 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 sleep.
How is OSA diagnosed?
- The diagnosis is usually based upon the person’s medical history, physical examination, and testing.
- Testing is usually performed in a sleep laboratory by a doctor or an ENT specialist.
- 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 arms/legs.
- 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.