I was just researching something for a new member and came across an overly complicated way to calculate AHI:
Quote:To determine 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.
Apnea + Hypopnea divided by actual sleep time, then multiply by 60
200 apneas, 200 Hypopneas (400 Total Events)
420 Minutes Actual Sleep Time (7 hours x 60)
Divide 400 by 420 = .95 x 60 = 57 AHI (Severe OSA)
At first it made no sense. The info was on the website of a sleep lab. Going on the assumption that they track minutes, not hours, it makes slightly more sense, but only a little. They reach the number of minutes by taking the hours and multiplying by 60. Then putting that 60 right back in again. I can see the usefulness if, say, someone slept 6 hrs and 43 minutes. It would indeed help with that.
So I tried it out.
Let's say I had 200 apneas, 200 hypopneas for a total of 400 events.
I slept for 6hrs and 43 minutes. That would be 6x60=360+43=403.
400 events divided by 403 minutes = .992 then x 60 = AHI of 59.55
Now, let's round up. 400 / 7 = 57.14
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 2.41?
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