What is Sleep Apnea and How Does CPAP help?

Posted on 06 Mar 13:23

What is sleep apnea?

Sleep apnea is a disorder that causes you to stop breathing while you are sleeping. Sleep apnea can be potentially fatal with harmful short term and long term complications that affects 1 in 3 men and 1 in 6 women. A sleep study is the best way to diagnose and order treatment pressure for sleep apnea patients. During the sleep study the AHI(Apnea Hypopnea Index) is measured by monitoring how many times per hour the patient stops breathing during sleep.

What is my AHI?


The average number of apneas plus hypopneas per hour of sleep:
Normal: 0-5
Mild: 6-15
Moderate: 16-30
Severe: greater than 30

The apnea-hypopnea index (AHI) is an index of severity that combines apneas and hypopneas. Combining them both gives an overall severity of sleep apnea including sleep disruptions and desaturations (a low level of oxygen in the blood). The apnea-hypopnea index, like the apnea index and hypopnea index, is calculated by dividing the number of apneas and hypopneas by the number of hours of sleep.

Hypoxia is defined as a reduction in airflow of 30% or more for at least 10 seconds and a reduction in oxygen saturation of 3% or greater coupled with an arousal from sleep to restart breathing.

Apnea is the complete stoppage of the airflow that occurs when the upper airway resistance in the nose and throat causes enough of a force to close the airway or the tongue falls back and blocks the airway and completely stops the flow of air for a period of at least 10 seconds, causing a reduction of oxygen saturation of 3% or more and an arousal from sleep to resume breathing. .

RDI  - R E S P I R AT O R Y  D I S T U R B A N C E I N D E X
The average number of apneas plus hypopneas plus arousals (not meeting the apnea hypopnea definitions) per hour of sleep
When either hypoxia or apnea occurs, they are scored as a respiratory disturbance event. The number of events per hour is referred to as the RDI-Respiratory Disturbance Index.  

What causes sleep apnea?

There are three main types of sleep apnea:

Obstructive sleep apnea (OSA), which 84% of sleep apnea patients have, occurs when enlarged and/or relaxed throat muscles obstructing your upper airway which are blocking air from entering and leaving your lungs.

Central sleep apnea (CSA), Central apneas are named for relation to the central nervous system and occurs when the brain stops signalling for the body to breathe until it detects a lack of oxygen or heightened level of carbon dioxide that needs to be exhaled.

Complex sleep apnea (CompSA) is a combination of OSA and CSA.

Eventually your brain senses that you’ve stopped breathing and causes you to wake up just enough to gasp and start breathing again. Then you fall back to sleep and the cycle begins again. This can happen more than 120 times every hour, even though you may not remember waking up.

Sleep apnea can put stress on the body causing other health issue to develop.

Short-term effects of sleep apnea

Sleep apnea can cause immediate life threatening danger of not inhaling enough oxygen (or exhaling enough poisonous carbon dioxide) and the body’s constant waking due to these apneas can also cause sleep deprivation. Untreated sleep apnea lowers  energy and attentiveness. In addition sleep apnea raises the risk of memory loss and can lead to cognitive impairment and injury.

Long-term effects of sleep apnea

Sleep apnea has been linked to cause increased risk for chronic and life-threatening conditions such as hypertension (high blood pressure) and heart failure, as well as poorer glucose control in patients with type 2 diabetes.

The first step toward treating sleep apnea and living healthier is recognizing the signs and symptoms of sleep apnea and asking your doctor to get screened and tested. Roughly 80% of people with sleep apnea don’t know they are experiencing sleep apnea.

Sleep Apnea Symptoms

Common sleep apnea symptoms include:

  • Waking up with a very sore or dry throat
  • Loud snoring
  • Occasionally waking up with a choking or gasping sensation
  • Sleepiness or lack of energy during the day
  • Sleepiness while driving
  • Morning headaches
  • Restless sleep
  • Forgetfulness, mood changes, and a decreased interest in sex
  • Recurrent awakenings or insomnia


Why use CPAP Therapy?

CPAP, Continuous Positive Airway Pressure, therapy uses a CPAP machine to help a person who has obstructive sleep apnea (OSA) breathe more easily during sleep. CPAP machines increases air pressure within the patients airway in order to keep the airway open during sleep.  

An important part of using CPAP is the mask used.  Depending on individual needs, a patient may use a nasal mask, a nasal pillow type mask, or a full face mask. 

Nasal Pillow Masks use a lightweight, soft cushion nasal mask to apply the pressure coming from the CPAP or BiPap machine.  People who do well with this type of mask are typically those who are prescribed a lower amount of pressure such as 4-13cm and who also breath through their nose and don't breath through their mouth as they sleep.  Although this type of mask can still work well with "mouth breathers" if a chin strap is also used.

Nasal Masks are designed to cover the nose and are held in place with a headgear. Several new nasal masks have come out lately from manufacturers such as ResMed and Fisher Paykel.  The new masks are designed to be more comfortable, lightweight, and seal well.  People do great on CPAP and BiPap therapy with a nasal mask when they breath through their nose and not their mouth as they sleep.  Although some "mouth breather" patients do well with nasal masks when used with a chin strap.

Full Face CPAP Masks cover both the nose and the mouth.  Full face masks are held in place with a headgear.  Patients who are "mouth breathers" do very well with full face masks.