Obstructive Sleep Apnoea for clinicians

Obstructive Sleep Apnoea (OSA) is a characterised by repeated collapse of the pharynx during sleep causing upper airway obstruction leading to recurrent oxygen desaturation and hypoxemia, hypercapnia, arousals from sleep and sleep fragmentation. These contribute to the adverse consequences of OSA, including cardio-metabolic and neurocognitive effects.

Moderate to severe OSA

Significant (moderate-to-severe) obstructive sleep apnoea affects 50% of adult men and 25% of adult women (see Heinzer R, Vat S, Marques-Vidal P, et al. Prevalence of sleep-disordered breathing in the general population: the HypnoLaus study. The Lancet Respiratory medicine. 2015;3(4):310-318. doi:10.1016/S2213-2600(15)00043-0).

Symptoms of OSA

People with obstructive sleep apnoea report:

  • snoring
  • witnessed apnoeas
  • waking up with a choking sensation
  • excessive daytime sleepiness.

Other common symptoms are:

  • non-restorative sleep
  • insomnia (difficulty initiating or maintaining sleep)
  • fatigue or tiredness
  • nocturia
  • morning headache

Daytime symptoms can include irritability and mood changes.

Physiological factors

Although obesity is a common risk factor, many people with OSA are not obese. Other physiological factors that influence OSA risk in individuals include:

  • the activity of the upper airway dilator muscles
  • instability of the respiratory control system (high loop gain)
  • propensity to arouse from sleep (arousal threshold).

Fluid retention and fluid shifts overnight may also play a role. Craniofacial anatomy can be important in some people.

Consequences of OSA

Consequences of OSA include excessive daytime sleepiness and fatigue, and reduced quality of life, particularly in younger and middle-age individuals. A large body of evidence has shown OSA leads to hypertension. These problems have been shown in randomised clinical trials to improve with treatment. OSA has also been linked in a large number of studies to increased:

  • mortality risk
  • cardiovascular disease (including stroke, myocardial infarction and heart failure)
  • diabetes
  • nocturia
  • erectile dysfunction
  • renal impairment
  • depression
  • cognitive impairment
  • risk of accidents.

Referrals and treatments for OSA

Referral for investigation should be considered in any person with any symptoms (see above). There are a number of treatment options for OSA. All people with OSA can benefit from weight loss, and in mild OSA this may be all that is needed. For others, commonly used treatments include Continuous Positive Airflow Pressure (CPAP) or oral devices (mandibular advancement device). Studies show adherence to CPAP is 60–70%, much the same as adherence to asthma inhalers, oral anticonvulsants and maintenance of good glycemic control in diabetes. Newer therapies include hypoglossal nerve stimulation.

Fitness to drive is an important consideration in assessing people with OSA. Guidelines require practitioners to consider excessive daytime sleepiness, drowsiness while driving, history of accidents as well as adherence to treatment when making an assessment of fitness to drive. Commercial licence standards are more stringent.

Further information

  • Jordan AS, McSharry DG, Malhotra A. Adult obstructive sleep apnoea. Lancet. 2014;383(9918):736-747. doi:10.1016/S0140-6736(13)60734-5
  • Assessing fitness to drive

This information has been developed by SA Health and The University of Adelaide