Dr.ª Inês Belchior

Pulmonologist 

Diagnosing sleep apnoea can save your life

HPA Magazine 7

In recent years we have heard more and more about Obstructive Sleep Apnoea and the risks to the life of sufferers, yet very few people know much about it.
Sleep Apnoea is an ancient disorder but it was only recently identified. We are speaking of a period of about 40 years in which more and more has been discovered about the disorder, its consequences and its treatment.

It is estimated that it affects around half a million people in Portugal but we know that it is very underdiagnosed. 
What happens in this condition is that during sleep, the person’s stops breathing for a few seconds (apnoea) and only manages to breathe normally after an interruption of sleep (which may have consequences) and, is generally followed by a loud snort. This stoppage can be merely partial, in this case called hypopnoea. Both types of breathing pauses (total or partial) cause a significant reduction of oxygen in the blood, which is prejudicial for the sufferer. The severity of the disorder increases with the number of apnoeas/hypopnoeas, which in some cases can be extreme, numbering 500 pauses per night and apnoeas of 1 minute in duration! These events are often noted only by a partner or spouse and are the reason that brings them to consult a doctor, because the sufferers do not realise what is happening, and can even believe they have slept well all night. Other frequent complaints are getting up several times a night to urinate, waking up tired, and having morning headaches.
Naturally this has implications in the quality of sleep of the sufferer, and consequent somnolence during the day, but it is quite variable. There can be individuals with 5 events per hour during the night who are very tired during the day and others with more than 30 per hour who do not have complaints, which makes it so difficult to identify and treat. Nowadays, driving  car is so indispensable that people drive even when extremely sleepy, and this has grave consequences for road safety, for the driver as well as for others.
Unfortunately, somnolence is far from being the only consequence of sleep apnoea. Although we do not say that someone died of apnoea, just as we do not say that someone died of high cholesterol or high blood pressure, all of these conditions greatly contribute towards the mortality of heart disease. We know that sleep apnoea is an important risk factor for heart attacks and arrhythmia, and that those who suffer from sleep apnoea, if treated, will have a lower risk of death and improve their heart health. The same is true for incidences of strokes, which are the cause of severe disability. We know that sleep apnoea is related to strokes, especially those that happen upon wakening. The treatment is also worthwhile because it has shown that patients who survive a first stroke are at a reduced risk for having another, if treated for that condition.

The lack of oxygen reaching our cells during the night, caused by sleep apnoea, affects all of the organs of the body, and the brain is no exception. In these patients, an accelerated degeneration of cerebral capacity is noted, with “memory loss” being one of the many complaints they might make.
Currently the treatment for sleep apnoea does exist, although with variable success, depending on the method chosen and the severity of the disorder. The use of a nasal CPAP (Continuous Positive Airway Pressure) is very efficient and always used in severe cases. Other treatments, such as surgery or a mouth apparatus can be used for less severe cases and adequately selected.
As this is a treatable condition, with obvious benefits for the sufferers, a diagnosis and proper course of action are essential. For this, an exam that registers breathing pauses, heartbeat and oxygen level, among other indicators, must be made during sleep. This exam can be made with a device that the patient takes home and sleeps with, or in special cases, must be done in a Sleep Laboratory. If you think you might have sleep apnoea, talk it over with your doctor or seek help from your pulmonologist.

POLYGRAPH SLEEP STUDY OR POLYSOMNOGRAPHY
This exam captures the physiological indicators (respiratory, neurological, cardiac) and the movements of the individual during sleep, by means of sensors. It can be done at home or in a Sleep Laboratory. When done at home, the indicators gathered are the following:
> Oxygen saturation and heartbeat;
> Snoring;
> Breathing patterns and respiratory events;
> Body positions.

When the exam is done in a hospital, the assessment is more far-reaching, consisting of the previous indicators plus the following:
> Electroencephalogram (brain waves and phases of sleep);
> Electrooculogram (eye movements);
> Electrocardiogram (cardiac rhythm and pulse);
> Electromyogram (leg movements).