CDHB
Obstructive Sleep Apnoea (OSA) is a common medical problem occurring in at least (but not confined to) 4% of the middle-aged population. OSA is part of a spectrum of sleep-disordered breathing characterized by disturbed sleep arising from increased upper airway resistance. Risk factors for OSA include obesity, increased neck circumference, craniofacial abnormalities, hypothyroidism and type 2 diabetes. OSA is associated with excessive daytime sleepiness and sufferers are at increased risk of motor vehicle accidents. OSA is also becoming increasingly recognized as an important risk factor for cardiovascular disease.
Patients who present with a history of loud snoring and excessive daytime sleepiness should be considered for investigation of OSA. Snoring and excessive daytime sleepiness are both markers of adverse outcome, but are very prevalent (approximately 40% of the adult population report snoring and/or excessive daytime sleepiness) and are non-specific. Other clinical features which may suggest OSA include a history of disturbed or unrefreshing sleep, sleepiness-related accidents, resistant hypertension, and nocturnal cardiac arrhythmias.
For patients with suspected OSA, two initial screening tests are recommended to facilitate timely and appropriate management:
An ESS of >10 is considered abnormal, with a score of >16 indicative of pathological daytime sleepiness. An elevated DI (≥10) is relatively specific for OSA. However it should be noted that oximetry is insufficiently sensitive to exclude OSA, and may miss up to 30% of patients with significant disease. If there is a high level of clinical concern regarding OSA but normal oximetry, further assessment (which may include more detailed testing such as a Level 3 or Level 1 Sleep Study - full overnight polysomnography) should be considered.
In general, if the ESS and DI are elevated, or if there is a high degree of concern regarding OSA even if the DI is <10, then patients should be referred to the Sleep Disorders Unit for clinical evaluation. Referrals can be made on either a standard inpatient consultation form or using a Sleep Studies Request Form.
Epworth Sleepiness Score
Epworth Sleepiness Score |
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How likely are you to doze off or fall asleep in the following situations, in contrast to feeling just tired? This refers to your usual way of life in recent times. Even if you have not done some of these things recently, try to work out how they would have affected you. Use the following scale to choose the most appropriate number for each situation: |
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0 = would never doze 1 = slight chance of dozing |
2 = moderate chance of dozing 3 = high chance of dozing |
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Chance of Dozing |
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Sitting and reading |
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Watching television |
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Sitting inactive in a public place (e.g., theatre, meeting) |
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As a passenger in a car for an hour without a break |
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Lying down to rest in the afternoon when circumstances permit |
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Sitting and talking to someone |
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Sitting quietly after lunch without alcohol |
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In a car, while stopped for a few minutes in the traffic |
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Obesity is the most important risk factor for OSA, and weight loss strategies should be explored for all overweight OSA patients. Other lifestyle measures which may be of benefit include minimizing supine sleep, and avoiding precipitants of upper airway obstruction such as alcohol and nocturnal benzodiazepines.
The most common initial treatment for OSA is CPAP (Continuous Positive Airway Pressure). A CPAP unit generates air pressure which provides a pneumatic splint to the upper airway which is delivered via a nasal or full-face mask during sleep. CPAP has been shown to effectively normalize the breathing disturbance in OSA and significantly reduce the driving and cardiovascular risk. All requests for CPAP must be made through the Sleep Disorders Unit and be approved by a Sleep Physician. It should be noted, however, that not all patients referred may qualify for hospital funded CPAP therapy.
Another option for treatment of OSA is a MAS (Mandibular Advancement Splint). This may be the preferred treatment for patients with mild OSA or those who are intolerant of CPAP. Upper airway surgery also has an important role in the treatment of OSA, particularly for those patients where there is a clearly defined anatomical abnormality such as enlarged tonsils or retrognathia (small lower jaw). Referral for these treatment options should be undertaken in conjunction with a Sleep Physician.
Topic Code: 1629