Sleep apnea is a relatively common disorder where a person stops breathing periodically during the night. This stoppage of breath usually lasts around 10 seconds or longer. This can occur only a couple of times a night but in some severe cases, apnea can take place hundreds of times a night.
Sleep apnea can be a vicious cycle as it causes people to wake up. As soon as you stop breathing during sleep, the brain is alerted and makes you wake up to start breathing again. However, most of the time, people don’t realize that they have woken up.
Therefore, they will feel lethargic and tired the following day, even if they think they had a full night’s sleep. If untreated, this can lead to a variety of health problems and even depression.
Although sleep apnea can differ from person to person, a rate of 0 to 5 sleep apnea events per hour is thought to be normal. 5 to 14 sleep apnea events can be classified as mild sleep apnea while 14 to 29 apnea events per hour is considered moderate sleep apnea.
Those who suffer severe sleep apnea are thought to suffer from 30 or more events per hour and these patients can even experience hundreds of events every night.
If you believe you may have sleep apnea, you should consult your doctor immediately. They will make an evaluation of your symptoms and signs. If required, they will then refer you to a sleep disorder clinic for further treatment and care.
How many apneas per hour is severe?
As we mentioned, there are different levels of sleep apnea. A lot of the time, the number of apnea events someone experiences during the night depends on the form of sleep apnea they have. Overall, there are 3 forms:
Central sleep apnea is less common than obstructive sleep apnea (OSA). This occurs when the brain fails to send a signal to the breathing muscles. Most of the time, conditions that influence the brain stem are found to be the leading cause of central sleep apnea.
Obstructive sleep apnea is when an airway becomes completely or partially blocked. The fatty tissue in the neck or the tongue will fall into the back of the mouth as the throat muscles relax during sleep. This leads to the airflow becoming blocked.
Mixed sleep apnea is a combination of central sleep apnea and obstructive sleep apnea and can cause many apnea events per night.
When it comes to the severity of this condition, it is generally found with how many sleep apnea events and hypopnea events take place during sleep. This classification takes place through the Apnea-Hypopnea Index.
Once the apnea events are counted, they are then divided by the hours of sleep the patient had. The higher the Apnea-Hypopnea Index result is, the more severe the sleep apnea is.
If somebody has 30 or more sleep apnea events per hour, then it is regarded as severe. Most people who have severe sleep apnea suffer from obstructive sleep apnea and may have to wake up hundreds of times every night. This will then leave them exhausted and irritable during the following day which, over time, can lead to depression.
Severe sleep apnea can also pose serious health risks such as heart disease and diabetes. Recent studies also found that those who suffer from severe sleep apnea have a higher risk of suffering very serious and fatal conditions such as cancer.
What are events with a CPAP?
CPAP, or Continuous Positive Airway Pressure, therapy is a common treatment for obstructive sleep apnea. When a patient uses a CPAP machine, a hose and mask, or nosepiece, is used to deliver constant, steady air pressure.
However, these machines can run into problems with leaky masks, the patient finding it hard to fall asleep, and the onset of a stuffy nose or dry mouth.
CPAP machines are the most prescribed devices for treating sleep apnea disorders. They measure how you sleep and how many interruptions or pauses in your breathing take place during this time. This is often because the throat or airways briefly collapse or something blocks them temporarily.
While these machines are regularly used by sleep apnea patients, many wonder what an event is with the CPAP. These events are sometimes referred to as an Apneic Event or episode. This is a pause in the breathing that lasts for 10 seconds or more. The stoppage of breath has to last at least 10 seconds to be classified as an event.
Obstructive apnea events can last as long as two minutes but this is usually in severe cases. Such long breaks in breathing are generally associated with a reduction in the oxygen levels in the blood.
Over time, this can cause potentially serious health problems as your organs are left without sufficient oxygen supplies and blood flows for some time.
Furthermore, many sleep apnea sufferers may not even know that this is happening to them and these stoppages could occur many times throughout the night. This is why CPAP machines are used so doctors can discover how severe a patient’s sleep apnea may be.
What does AHI mean on a sleep apnea machine?
Sleep apnea machines have one main goal and that is to improve breathing. To diagnose the severity of the sleep apnea with a patient, the apnea-hypopnea index (AHI) is used. This measures the severity of the condition at baseline and helps track the effectiveness of any treatment.
The AHI measurement is usually presented in a sleep study report. It is the number of times per hour of sleep that the upper airway (soft palate of throat or tongue) completely or partially collapses. This leads to a brief awakening or a drop in blood oxygen levels.
The AHI can classify the severity of the sleep apnea and assess how well treatment is going with machines such as the CPAP. To count in the AHI, the breathing pauses must last for at least 10 seconds or be associated with the decrease of oxygen levels in the blood.
Damon Wiseley is a Registered Respiratory Therapist and Certified Pulmonary Function Technologist.