What is OSA?

Normally when we sleep, muscles hold our airway open. If these muscles relax, the airway can become narrowed or even completely closed (obstructed), preventing normal breathing.

The closure of the airway, called obstructive apnoea causes the affected person to wake up. Once awake their airway opens and normal breathing resumes allowing the person to quickly go back to sleep only to have the airways relax, initiating the next apnoea. This sequence of events may be repeated over and over again - up to hundreds of times a night! This condition is known as Obstructive Sleep Apnoea (OSA).

As a result of the continual awakenings caused by OSA, those affected suffer from severe sleep deprivation and fatigue. Unfortunately, people with this condition are often completely unaware that they have been woken up throughout the night and are oblivious to the reason for their tiredness.

Up to 9% of the middle-aged population has OSA. Loud snoring punctuated with pauses can be a sign that maybe someone is effected by this condition. Being overweight may also increase the likelihood of having OSA along with a family history of this condition, and structural abnormalities of the upper airways.

Untreated OSA may lead to serious health problems such as high blood pressure, heart attack and stroke. OSA also causes memory loss, poor concentration, morning headaches and sexual dysfunction.

Does CPAP therapy have side effects?

Continuous Positive Airway Pressure (CPAP) therapy is very safe and helps to improve the life of thousands of OSA sufferers every day. However, there are some side effects which can discourage the OSA sufferer from persisting with CPAP treatment.

A common side effect is a sore, dry nose and throat which is often caused by mouth leak. This occurs when the user opens their mouth while they are asleep. Because there is air that is under pressure in the airways, it will travel out the mouth - the path of least resistance.

Some of the air from the CPAP machine travels to the user's lungs, but a large portion of the air travels straight out the mouth. This is called unidirectional flow.

This unidirectional flow dries out the airways, causing a dry nose and throat, nasal irritation and sometimes even nose bleeds.

A clinical study was conducted by Dr Glenn Richards and a team of respiratory physicians at the David Read Laboratory in Sydney, Australia which investigated mouth leak in response to CPAP therapy.

Dr Richards and his team found that in every subject in the study, mouth leak increased the amount of nasal airway resistance (NAR). It is likely that an increase in NAR results in nasal iiritation and that this could be largely prevented by the use of heated humidification.