The math of calculating AHI

[jjtisch3]

Thank you
John

[midwestguy]

Really, does it matter to be that freakin' exact? Anything over 30 is considered severe (I keep saying they need to revise that) so, does it matter to make a difference 

[...]

And, in spite of knowing that the AHIs reported by my machine may not be perfectly accurate, I still strive for the elusive zero AHI night. I came the closest ever last night when SleepyHead told me I had 0.09. I was thrilled, in spite of the fact that I felt terrible because I had a miserable night's sleep due to missing my bedtime. (Went to a Wagner opera and didn't get home until 1 am.)

[...]

Consider this: Your CPAP runs for 6 hours, mask on to mask off. Total events is 30. So AHI would be 30/6, or 5.0. However, your bedside clock showed that it took you one hour to fall asleep. So your actual therapy time is 5 hours, and your AHI is 30/5 or 6.0.

So the longer it takes you to fall asleep, the more inaccurate your AHI is.