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Apex CPAP  machines

What is Obstructive Sleep Apnoea? Is it related to snoring?

Obstructive Sleep Apnoea (UK and Australian spelling, or “Apnea” American spelling) can be viewed as an extreme version of snoring. In snoring, the soft palate (the soft piece of flesh forming the back roof of the mouth) vibrates during inhalation, producing the sound of snoring. The reason for the soft palate vibration is complex but it relates to the high speed of air passing through a narrow airway at the site of the soft palate. The narrowness is due, among many reasons, to either excessive relaxation during sleep of the muscles making the soft palate, or the subject is born with a narrow airway or has a long palate.

In obstructive sleep apnoea sufferers, the airway is even narrower than that of snorers for a variety of reasons. When sleep relaxes the muscles that make the upper airway, the airway narrows further and the air delivered to the lung is decreased. This results in a fall in oxygen (O₂) and rise in carbon dioxide (CO₂) in the blood. These serious changes alarm the brain during sleep, stimulating the brain to order the muscles of breathing (the diaphragm) to contract harder to get more air into the lungs. However, because the muscles of the upper airway tube are relaxed and the airway is narrow, this contraction of the diaphragm sucks in the walls of this tube (the soft palate and tongue), closing it completely. Under such circumstances, no air is delivered to the lungs, which leads to further falls in O₂ and a build up of CO₂ in the blood. Any further contraction of the diaphragm is useless in terms of getting air into the lungs because the airway is closed. The cessation of air (called apnoea) could last from 5 seconds up to 2 minutes, which leads to very serious life-threatening situation. Under such condition, the brain areas responsible for correcting the O₂ and CO₂ in the blood, having sensed the seriousness of the condition, order other parts of the brain to wake up (arousal) so as to activate the muscles of the upper airway and open the airway passage. This results in correction of blood O₂ and CO₂ to normal levels. However, the urge to sleep is very strong and the sufferer drifts back to sleep, repeating the cycle of airway closure during the rest of sleep.

What are the factors that worsen sleep apnoea?

Alcohol, especially when consumed in the evening/night-time results in excessive relaxation of the muscles and depresses arousal. Obesity also worsens sleep apnoea because it makes the upper airway easier to close during sleep as fat is deposited in between the muscles. All medications that weaken the muscles and depress arousal (for example, sleeping tables) also worsen sleep apnoea. The presence of large tonsils and deviated nasal septum could also worsen the condition. Finally, the mechanical problem of repeated forceful airway opening and airway closure associated with obstructive sleep apnoea itself traumatises the upper airway structures, leading to their swelling and further narrowing of the upper airway.

Is Sleep Apnoea a serious disorder?

Medical research in the last 40 years has shown that the combination of low O₂, high CO₂ in the blood during the apnoeas, and the sleep disruption (also called sleep fragmentation) affects many organs especially the heart, brain and kidneys. The combination also leads to a rise in blood pressure, irritability, headache, depression and mood changes, excessive daytime sleepiness, increase in body weight, forgetfulness, and sexual dysfunction, among other things. These changes could enhance the development of serious complications such as hypertension, stroke, and heart attacks.

Therefore, treatment of sleep apnoea is important in order to prevent the above abnormalities. CPAP is the safest/best treatment available at present especially for patients with moderate-to-severe sleep apnoea. See What is CPAP?