People with obstructive sleep apnoea (OSA) experience repetitive episodes of partial or complete closure of the upper-airway during sleep. Abnormal relaxation of respiratory muscles causes sufferers to snore, and to sometimes wake up gasping or choking.
While many people with OSA don’t realise their sleep has been disturbed, the condition causes excessive daytime fatigue and poor concentration.
As well as aviation, motor vehicle and industrial accidents, OSA increases the risk of:
- high blood pressure
- heart attack
- type 2 diabetes
- mood disorders.
When the respiratory muscles relax during sleep in OSA, soft tissues in the back of the throat collapse and block the upper airway. This leads to partial reductions (hypopneas) and complete pauses (apnoeas) in breathing lasting 10 seconds or more. Sleep clinicians measure the severity of OSA using the Apnoea Hypopnea Index (AHI) and oxygen desaturation levels. The AHI is the number of apnoeas or hypopnoeas recorded during the study per hour of sleep. It is generally expressed as the number of events per hour. Based on the AHI, the severity of OSA is classified as follows:
- none/minimal: less than 5 AHI per hour
- mild: more than 5 but less than 15 AHI per hour
- moderate: between 15 and 30 AHI per hour
- severe: more than 30 AHI per hour.
If you suspect that you have OSA or you have symptoms of OSA, you should see your general practitioner (GP). You may then be referred for a sleep study so that you can be investigated for OSA and other sleep disorders, to allow suitable treatment to be implemented if necessary.
The effect of aviation on the condition
OSA sufferers may find their condition worsens during aviation due to:
- irregular work and sleep hours
- difficulty carrying continuous positive airway pressure (CPAP) equipment when operating away from home
- lifestyle factors leading to increased BMI.
The effect of the condition on aviation
- increased risk of cardiovascular disease, cerebrovascular disease, insulin resistance, hypertension and congestive heart failure.
- reduced attention and concentration
- degraded cognition.
Implications for pilots and controllers
If you are diagnosed with OSA you must ground yourself and obtain a Designated Aviation Medical Examiner (DAME) review.
Moderate and severe sleep apnoea is associated with accidents and health problems. Fortunately modern CPAP machines are highly portable. If the CPAP machine you use does not have a data download function, you may need to provide CASA with additional annual specialist reports, sleep studies or other tests.
- You are not to fly if you experience any problems with your treatment or experience a recurrence of your symptoms.
- If you are using CPAP, you should use it for at least five hours per night and for six nights per week. It must be used during the sleep period just prior to flight.
- Effective control reduces the risk of cardiovascular disease, cerebrovascular disease, insulin resistance, hypertension and congestive heart failure.
- CASA may be able to issue Class 1, 2 and 3 certification if you can show evidence your condition is being satisfactory controlled.
- Once you can demonstrate effective OSA management and stability you may only need to show CASA your CPAP download to satisfy review requirements.
- In case of other treatment modalities, CASA will need you to provide other evidence of control of this condition.
- CASA requires annual review of Class 1 and 3 sufferers of OSA.
Approach to medical certification
More likely to be certified
You are more likely to be certified or re-certified if:
- you can show CASA objective measures which demonstrate your OSA is under control.
Less likely to be certified
You are less likely to be certified or re-certified if:
- you experience symptomatic OSA
- you show inadequate compliance with treatment regimes
- you have poor AHI control.
You are unique
Every case of OSA is different. How you are affected by OSA will depend on a range of circumstances. CASA makes aeromedical decisions on a case by case basis. A particular assessment decision is based on the individual circumstances of the applicant under consideration.