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Sleep apnoea

by Alexandra Middleton | 14 Oct 2013

Do you snore? Wake up a lot during the night? Five per cent of Australians experience sleep apnoea, including one in four men over the age of 30.

What is sleep apnoea?

Sleep apnoea is a disorder where the walls of an individual’s throat come together during sleep, disrupting their breathing. The disruption occurs repeatedly throughout a single night’s sleep and generally lasts from 10 seconds to one minute.

Each time breathing stops the brain registers the lack of oxygen and triggers the individual to wake up. The sleeper may only rouse slightly, generally snorting or gasping, however this is enough to open their upper airways and restore air flow to the brain.

Around five per cent of Australians experience the disorder, with one in four men over the age of 30 years affected.

Symptoms

Common symptoms of the disorder include:

  • Daytime sleepiness
  • Snoring
  • Loss of airflow or choking during sleep
  • Morning headache
  • Poor memory
  • Restless sleep
  • Breathlessness at night or day
  • Behavioural changes and irritability
  • Reduced sex drive
  • Heart burn at night
  • Needing to go to the toilet multiple times a night

Often the sleeper themselves will not be aware of their restless sleep patterns, but are alerted to their occurrence by a partner.

Diagnosing sleep apnoea

The severity of an individual’s sleep apnoea is measured using the Apnoea Hypopnoea Index (AHI) measured through an overnight sleep study.

To determine AHI, the number of apnoeas (complete loss of airflow) is added to hypopnoeas (50 per cent reduction in air flow) divided by the number of hours of recorded sleep.

An AHI of five or more indicates the presence of sleep apnoea, and a measurement above 30 indicates a severe level of the disorder.

There are four different methods or levels of sleep investigation that individual’s can undergo.

Level one: Polysomnography (sleep study) and overnight observation in a specialist unit. This investigation requires individuals be monitored by respiratory, limb and EEG leads.

Level two: Polysomnography in the comfort of your home. This requires individuals to be connected to the same monitors as level one.

Level three: Monitoring of respiratory parameters, and O2 saturation and pulse rate using a finger monitor. This study is undertaken in the home.

Level four: Measuring O2 saturation and pulse overnight in the home.

The Australasian Sleep Association says that level one testing is gold standard, but expensive. The majority of individuals showing symptoms of sleep apnoea will undertake a level three or four test and have their results analysed by a sleep specialist.

Causes of sleep apnoea

There are a number of causes of sleep apnoea, but by far the most common is obesity.

Individuals with excess weight around the neck or abdomen are particularly at risk, as are men and women with a large neck circumference (more than 43cm for men and more than 40cm for women.

Other contributing factors include:

  • Alcohol, particularly if consumed before bed
  • Illnesses such as low thyroid function
  • Large tonsils
  • Nasal congestion
  • Facial bone structure

Treatment of sleep apnoea

As well as losing weight and maintaining a healthy lifestyle, a fairly non-invasive and readily available treatment involves wearing a continuous positive airway pressure (CPAP) mask at night.

The mask works by forcing air through the nose preventing the throat from closing. While some consider the mask to be bulky, it is an extremely effective form of treatment and avoids undergoing a surgical procedure.

A mouthguard can also be worn that acts as a splint, holding an individuals jaw forward and their airways open while they sleep.

Lastly, individuals can undergo surgery to the palate of their mouth and tongue, however these procedures are not proven to be completely effective at curing the disorder.