Understanding AHI

Posted by theamericanbrit @theamericanbrit, Apr 2 8:00am

I use an AirSense 11. I don't quite undestand "Events". my readings have gone for .08 to 3 but the seal is good. Is a lower number good or the higher number bad - I am confused 🙁

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John, Volunteer Mentor | @johnbishop | Apr 2 8:23am

Hi @theamericanbrit, I think your AHI numbers are great. When I had an overnight sleep study at Mayo Clinic, I had over 55 events (AHI) and was diagnosed with severe obstructive sleep apnea. My sleep medicine doctor prescribed a CPAP and gave me a target to try and keep my AHI under 4. I still have some days over 4 but I keep working on it. I do notice that when my AHI is under 4 I seem to feel more rested when I wake up. Here's some information that may help you understand it a little better.

"How many AHI events per hour is normal?
Apneas are periods when a person stops breathing and hypopneas are instances where airflow is blocked, causing shallow breathing. Normal AHI is less than 5 events per hour, while severe AHI is more than 30 events per hour."
--- Understanding the Apnea-Hypopnea Index (AHI): https://www.sleepfoundation.org/sleep-apnea/ahi

theamericanbrit | @theamericanbrit | Apr 2 9:05am

In reply to @johnbishop "Hi @theamericanbrit, I think your AHI numbers are great. When I had an overnight sleep study..." + (show)

Thank you, yes your answer was very helpful. I also feel much better if my numbers are low but I think that maybe having a cold, elevated my number last night 😢
I also have COPD so I guess I can’t complain 🤣

Sent from Yahoo Mail for iPhone

gloaming | @gloaming | Apr 4 4:45pm

The medical community and the insurers rate any AHI less than 5.0 as treated. I don't know the history behind this figure, but it seems high to me. I personally run, month-to-month, with an AHI near 0.6, meaning I get one event every two hours approximately. Untreated, I am closer to 30 events per hour. The events measured and used in the calculation are three: obstructive events, open airway events, and hypopneas. The RESMED machines simply record an 'open airway' event if it's a central apnea where you fail to breath regularly. The machines can pulse air and wait to sense a blockage if you stop breathing. If it senses no return pulse from a close-by obstruction, it feels that your airway is open, but you're not breathing. That is central apnea.
The AHI calculation is simply this: events recorded divided by hours slept. 25 events and seven hours of machine use = 3.6 events/hour. This is much better than three times that many, but with some fine tuning, often the number can be halved. This puts less of a strain on your heart and means fewer sleep interruptions.