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Obstructive sleep apnoea (OSA)

Sleep apnoea is a common and potentially serious condition in which a person stops breathing during sleep. Typical symptoms include snoring, not feeling refreshed on waking, day-time sleepiness, altered mood, and morning headaches.  

There are two types of sleep apnoea: obstructive sleep apnoea (the more common type) and central sleep apnoea (which is rare). This article discusses obstructive sleep apnoea (OSA). OSA can occur at any age (including infancy) but is most common in middle-aged males.

In New Zealand, OSA is estimated to affect at least 4% of men and at least 2% of women.

Causes

In deep sleep, the muscles of the throat relax. This does not normally cause any problems with breathing. However, if you have OSA, the muscles at the back of the throat become so relaxed during sleep that part of the airway is closed off. 

You keep trying to breathe but no air enters the lungs and the level of oxygen in the blood drops (hypoxia). This eventually leads to semi-wakening and breathing resumes, usually accompanied by a loud snort or gasp. 

A person affected by OSA is often unaware that they have woken and immediately returns to sleep. Once asleep, the muscles relax again and the whole cycle recurs. This can happen many times each night which, as with insomnia, reduces the quality and benefits of a good night’s sleep. Loud, bothersome snoring is also a feature of OSA.

The risk of OSA is higher if:

  • A person is overweight. Excess weight on the outside of the throat increases pressure on the inside of the throat, which narrows the airway.
  • Alcohol, sedatives, or sleeping tablets are used prior to going to sleep. These can further relax the muscles around the throat making people more susceptible to OSA.
  • A condition that leads to excess tissue in the airway is present, eg: enlarged tonsils or jaw deformities.
  • Nasal obstruction is present.
  • A person has asthma.
  • A person is a smoker.

Symptoms

There are a number of signs and symptoms that may indicate that OSA is occurring. Often, the first indication is reports from others in the household about noisy snoring while asleep. OSA can lead to:

  • Waking up feeling as if you have not had enough sleep
  • Morning headache
  • Dry or sore throat
  • Feeling sleepy throughout the day
  • Difficulty concentrating
  • Loss of interest in sex and impotence in males
  • Memory loss
  • Personality change
  • Grumpiness and bad temper. 

OSA and other health problems

In addition to its possible impact on quality of life, some studies have shown that people with OSA are at greater risk of developing the following health conditions:

Due to feeling sleepy throughout the day there can be a propensity to fall asleep while driving, which is obviously very dangerous. 

Diagnosis

As there can be many reasons for disturbed sleep or daytime sleepiness (including rare conditions such as narcolepsy) diagnosing OSA can be difficult. If OSA is suspected, referral to a respiratory physician and/or an ear, nose, and throat specialist may be required. 

A doctor will take a detailed history of the problem and will examine the throat for signs of narrowing. It may often be helpful for the person's spouse/partner to be present, as they may be better able to explain what happens to the person during sleep. 

Tests may be used to confirm the diagnosis. Polysomnography (a type of sleep study) is the most comprehensive test undertaken to confirm OSA. This involves an overnight stay in a specially equipped sleep clinic where blood oxygen levels, brain activity, eye movement, and other indicators can be monitored.

Treatment

OSA needs to be managed firstly through lifestyle changes, often in combination with other treatments.

Lifestyle and behavioural changes

In cases of mild OSA, lifestyle changes may lead to improvement in the condition:

  • Weight loss. Even a small loss in weight can improve symptoms
  • Avoiding alcohol for at least a few hours prior to going to sleep
  • Avoiding sleeping tablets or sedatives
  • Taking measures to assist sleeping on one's side rather than on one's back, as OSA can often be worse when sleeping on the back
  • Quit smoking
  • Regular exercise.

Positive airways pressure therapy

Continuous positive airways pressure (CPAP) is the most common treatment for OSA. It involves the use of a pump that delivers continuous low pressure air into the airways during sleep via tubing and a mask fitted to the nose. 

If the results of the sleep study clearly indicate OSA, a CPAP machine is often fitted and adjusted to the appropriate settings while the study is in progress. Many people find they feel much better within a few days of commencing CPAP as they get the benefit of deep restorative sleep that they previously lacked.

Variations of air pressure machines adjust pressure if the device senses increased airway resistance, or deliver a pre-set level of pressure when you breathe in and a different level of pressure when you breathe out.

Dental appliances

 A number of dental appliances or devices can help to hold the jaw and tongue in a particular position to help keep airways open. These need to be fitted by a dentist or orthodontist and can have side effects such as damage to teeth and soft tissues. They are most effective in cases of mild OSA.

Surgery 

Surgery may be an option to address specific abnormalities that contribute to the obstruction of airways, including procedures to remove the tonsils and adenoids, correct deformities in the nasal passages, and remove excess tissue from the back of the throat or tongue. 

If other treatments have failed, jaw surgery may be considered. It involves moving the upper and lower parts of the jaw forward, which enlarges the space behind the tongue and soft palate and reduces the potential for obstruction. Surgery can also improve tolerance of nasal CPAP and improve effectiveness of dental devices. 

An individual should discuss with their doctor what surgical options might be relevant to their specific situation. 

Further support

The Sleep Apnoea Association of New Zealand is a support group that provides information and support to people with sleep apnoea and their families.

Sleep Apnoea Association of NZ Inc.
Phone: 021 344 253 
Website: www.sleepapnoeanz.org.nz 

References

Asthma and Respiratory Foundation NZ (date not stated). Obstructive sleep apnoea (Web Page). Wellington: Asthma and Respiratory Foundation New Zealand. https://www.asthmafoundation.org.nz/your-health/obstructive-sleep-apnoea [Accessed: 15/06/20] 
Wickramasinghe, H. (2019). Obstructive sleep apnea (Web page). Medscape Drugs and Diseases. New York, NY: WebMD LLC. https://emedicine.medscape.com/article/295807-overview [Accessed: 15/06/20] 
Mayo Clinic (2019). Obstructive sleep apnea (Web Page). Rochester, MN: Mayo Foundation for Medical Education and Research. https://www.mayoclinic.org/diseases-conditions/obstructive-sleep-apnea/symptoms-causes/syc-20352090 [Accessed: 15/06/20] 
O’Toole, M.T. (Ed.) (2017). Obstructive sleep apnea. Mosby’s Dictionary of Medicine, Nursing & Health Professions (10th ed.). St Louis, MI: Elsevier. 

 

Reviewed – June 2020

 
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