Your Sleep Apnea Type and AHI
We are going to explore the 3 commons types of sleep apnea and the clinical definitions of each. We will also show you how your apnea hypopnea index (AHI) is calculated.
What are OSA, COMPSA, and CSA?
Obstructive Sleep Apnea (OSA) means that something is blocking your air passage while you are sleeping. When this occurs, your brain is signaled to wake up and breath. You might gasp for air or have deep breathing just long enough for the obstruction to pass without ever really waking up. OSA diagnosis ranges from mild to severe. It depends on the number of times in an hour that your breathing stops (apnea) or becomes very shallow (hypopnea). Apnea episodes may occur from 5 to 100 times an hour. More than five apneas per hour is abnormal. More than 30-40 per hour is considered severe sleep apnea.
Central Sleep Apnea (CSA) occurs because your brain doesn’t send proper signals to the muscles that control your breathing. Your breathing is not controlled and has repeated stops and starts during sleep. The condition is often caused by another comorbidity.
Complex Sleep Apnea (COMPSA) is diagnosed when the user is developing either or both central apneas and central hypopneas while using their CPAP.
These diagnoses affect the type of CPAP machine that you buy. The CPAP machine is still one of the best recommended machines for each initial diagnosis.
What is an Apnea-Hypopnea Index (AHI)?
Apnea-Hypopnea Index, also referred to as AHI, is a numerical measure that accounts for the number of pauses in your breathing per hour of sleep. It is what your treating Doctor uses to determine the severity of your diagnosis.
To calculate your AHI, add the total number of apnea events, plus hypopnea events and divide by the total number of minutes of actual sleep time, then multiply by 60 (100 apneas + 60 hypopneas = 160 divided by 240 minutes = .66 x 60 = 40 AHI).
|None/Minimal||AHI < 5 per hour|
|Mild||AHI ≥ 5, but < 15 per hour|
|Moderate||AHI ≥ 15, but < 30 per hour|
|Severe||AHI ≥ 30 per hour|
Successful CPAP therapy is determined by your compliance reporting and continued visits with your sleep treating Doctor. Your CPAP machine uses web based software or an SD data card to record this information. Users who can see their mask leakage rates may be encouraged to try a new mask that works better. And, being able to see the CPAP compliance numbers (AHI) can influence the user to make changes for the better.
If you want to know if you have sleep apnea, you can take our quiz on Find Out If You Have Sleep Apnea Quiz.