OBSTRUCTIVE SLEEP APNEA

Obstructive sleep apnea (OSA) is a condition where the walls of the throat relax and narrow during sleep, interrupting normal breathing.

There are two types of breathing interruption characteristic of OSA:

  • apnea– where the muscles and soft tissues in the throat relax and collapse sufficiently to cause a total blockage of the airway; it is called an apnea when the airflow is blocked for 10 seconds or more
  • hypopnea– a partial blockage of the airway that results in an airflow reduction of greater than 50% for 10 seconds or more

The term “obstructive” distinguishes OSA from rarer forms of sleep apnea, such as central sleep apnea, which is caused by the brain not sending signals to the breathing muscles during sleep.

In people with OSA the airway has narrowed as the result of a number of factors, including:

  • being overweight or obese
  • having a large neck
  • taking medicines that have a sedative effect, such as sleeping tablets
  • narrow airway, large tonsils, adenoids or tongue, or a small lower jaw
  • smoking or drinking alcohol, particularly before going to sleep

If you have obstructive sleep apnea, you may not realise it yourself. The condition is often first spotted by a partner, friend or family member who notices problems while you sleep.

Signs of OSA in someone sleeping can include:

  • loud snoring
  • noisy and laboured breathing
  • repeated short periods where breathing is interrupted by gasping or snorting
  • waking up frequently

Signs of OSA while you are awake can include:

  • feeling of inadequate sleep
  • feeling very sleepy during the day
  • poor memory and concentration
  • headaches, particularly in the morning
  • irritability and mood swings
  • depression

DIAGNOSIS

  • History and Physical Examination
    • The partner or household member’s observation may be valuable for the diagnosis
    • Airway abnormalities will be checked
      • Enlarged tonsils, obstruction, etc.
    • Diagnosis Tests
      • Sleep Laboratory Exams(polysomnography)
        • the patient will be asked to stay in the hospital overnight. The patient’s sleep pattern and activity will be observed by trained staff specializing in sleep disorders.
      • Home Testing
        • the sleep centre will teach you how to use portable recording equipment while you sleep at home. The equipment you are given may include:
      • a breathing sensor
      • sensors to monitor your heart rate
      • bands that are placed around your chest
      • oxygen sensors that are put on your finger
  • Determining the severity of OSA
    • The severity of OSA is determined by how often your breathing is affected over the course of an hour. These episodes are measured using the apnea-hypopnea index (AHI).
      • Severity is measured using the following criteria:
    • mild– an AHI reading of 5 to 14 episodes an hour
    • moderate– an AHI reading of 15 to 30 episodes an hour
    • severe– an AHI reading of more than 30 episodes an hour

 

TREATMENT

  • Lifestyle modification
    • losing weight if you are overweight or obese
    • stopping smoking if you smoke
    • limiting your alcohol consumption, particularly before going to bed
    • avoiding sedative medications and sleeping tablets
    • Sleeping on your side, rather than on your back
  • Continuous positive airway pressure (CPAP)
    • This is a small pump that delivers a continuous supply of compressed air to you through a mask that either covers your nose or your nose and mouth. The compressed air prevents your throat closing.
  • Mandibular advancement device (MAD)
    • An MAD is worn over your teeth when you are asleep. It is designed to hold your jaw and tongue forward to increase the space at the back of your throat and reduce the narrowing of your airway that causes snoring.
  • Surgery
    • Surgery to treat OSA is not routinely recommended because evidence shows it is not as effective as CPAP in controlling the symptoms of the condition. It also carries the risk of more serious complications.
      • A range of surgical treatments have been used to treat OSA. These include:
    • tonsillectomy– where the tonsils are removed if they are enlarged and blocking your airway when you sleep
    • adenoidectomy– where the adenoids (small lumps of tissue at the back of the throat, above the tonsils) are removed if they are enlarged and are blocking the airway during sleep
    • tracheostomy– where a tube is inserted directly into your neck to allow you to breathe freely, even if the airways in your upper throat are blocked
    • weight loss (bariatric) surgery – where the size of the stomach is reduced if you are severely obese and this is making your sleep apnea worse

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