Apnea-Hypopnea Index (AHI) measures sleep apnea severity. The AHI is the sum of the number of apneas (pauses in breathing) plus the number of hypopneas (periods of shallow breathing) that occur, on average, each hour.
To count in the index apneas and hypopneas, collectively called events, must have a duration of at least 10 seconds.
The AHI, as with the separate Apnea Index and Hypopnea Index, is calculated by dividing the number of events by the number of hours of sleep.
From the AHI rating chart here, we see that an index less that 5 is considered normal. For an Apnea-Hypopnea Index (or AHI) from 5 to 15 denotes mild sleep apnea. Fifteen to 30 is moderate, while a greater than 30 AHI is considered severe.
- AHI = sum of the number of apneas (pauses in breathing) plus the number of hypopneas (periods of shallow breathing) occurring, on average, each hour.
- Apneas and hypopneas, collectively called events, must last at least 10 seconds to count as events.
- The AHI is calculated by dividing the number of events by the number of hours of sleep.
What does a Central Apnea Chart look like since that number is not included in the AHI number?
Central apneas are indeed calculated in the AHI. Central apneas are still apneas
i started on a bi-pap machine 30 days ago. i had a terrible time for nearly the whole month in tryat ing to make the full mask work. I started calling to complain. I even went back in to the provider to see if the mask fit. finally, the manager, a respiratory therapist heard my pleas and called. she was at my house within the hour and gave me a different mask which has worked 100%. In the last 10 days, i have had 100% mask fit. The AHI is up and down and i dont know what makes the difference in higher or lower, but i think i am sleeping better and will hopefully improve as time goes by. i no longer dread putting on the machine and i no longer have red marks and pain from the ill-fitting mask. do not settle for an inferior fitting when you can get relief if the techs will only take the time that this manager did with me
Paula, it will take time for your apneas to start to decline. Your brain is still getting used to having air at night. I started my bipap last April, and after about a month, I was still getting 13 apneas an hour, but more alert and awake during the day. After a couple more months it dropped to 10, and after 8 months, I now average around 6.5 per hour. Still having good nights and bad, but that is part of the process. Hang in there.
What is the difference between AHI and RDI (respiratory disturbance index). I did some basic research and it seems like RDI is considered “more accurate” but the clear differences are not elucidated very clearly. Any small clarifications would be greatly appreciated.
Is .5 and 5 the same measure? What does it mean when your number increases from .5 to 1.0? The decimal point is confusing. Where do these numbers fall on the chart from normal to severe?