What is Central Sleep Apnoea?
While asleep, there may be pauses in breathing, which are called apnoeas. Up to five brief apnoeas an hour may be seen in normal adults. For people with central sleep apnoea (CSA), the apnoeas last longer and occur more frequently. The body does not make an attempt to breathe during these pauses. This is different to the more common Obstructive Sleep Apnoea (OSA). Patients with OSA struggle to breathe against a blocked airway. For patients with CSA, the airway is not blocked, there is just a pause in breathing efforts.
About ten percent of people with breathing problems during sleep have CSA. This affects the quality of sleep and they feel sleepy during the day. The person might also complain of Insomnia or other sleep problems. Loud snoring is not as common in CSA as it is in OSA.
What causes Central Sleep Apnoea?
The brain may be slow to respond to changes in oxygen and carbon dioxide levels in the blood when breathing slows down. This may occur in people who have had sleep apnoea for a long time. This is due to blunting of the breathing reflex. CSA may also be due to a slow circulation from heart failure having an effect on the normal breathing reflex pathway. This causes a pattern of over-breathing and then under-breathing (periodic breathing) or stopping breathing. Other causes of this pattern of CSA include some drugs (e.g. narcotics such as morphine) or having cerebrovascular disease (e.g. a stroke). These affect the breathing control centres in the brain.
CSA can also be due to weakness of the muscles that make the lungs expand and contract, such as in neuromuscular disorders like polio. It can be also be caused by an abnormality in the shape of the chest wall or the lungs being too stiff. This can lead to under breathing, called hypoventilation.
CSA can disturb your sleep. It can also make your body retain carbon dioxide. This can lead to morning headaches or confusion.
Assessment of Central Sleep Apnoea
This requires a thorough evaluation of all the possible causes and also a Sleep Study. This is done by a Sleep Specialists
What can be done about Central Sleep Apnoea?
- Drugs (e.g. narcotics) which may cause CSA may need to be reduced or stopped if you can. There are some other drugs which stimulate breathing. You might be able to try these.
- Positive airway pressure therapies can help many forms of CSA. CPAP – Continuous Positive Airway Pressure (CPAP) may work. Adaptive servo ventilation is useful for periodic breathing. Sleep hypoventilation responds well to bilevel ventilatory assistance.
- Oxygen therapy at night may be beneficial.
- Where heart failure is a factor, treatment of this with medications is important.
- Rarely a diaphragm pacemaker is used. This has been used in spinal cord injury patients or in congenital hypoventilation syndrome.