Why do numbers go up when pressure does?

[rested gal]

Does anyone even know where the AHI of 5 or less being "normal" comes from? Were there large scale controlled studies done that came up with that number, or was that just something arbitrary?

Good question. I'd be interested to know where that figure came from, too, just out of curiosity.

[That Sleep Tech]

I'm still looking. I have yet to find a place that implicitly states this however, after reading 10+ scientific journals on OSA I have come to the conclusion that an AHI of <5 has no statistical significance on the increase of health problems or sleep architecture. In other words and AHI of <5 is statistically the same as an AHI of 0. Most of the journals had a 95% confidence interval with some at a 99% confidence interval. 95% is the standard.

[rested gal]

Thanks for looking, TST. I did some Googling and couldn't find any place that said, "This is why an AHI less than 5 is considered normal." Kept seeing that number used, but no "this is where it started."

You're probably right... that the early researchers concluded that "AHI of <5 has no statistical significance on the increase of health problems or sleep architecture. In other words and AHI of <5 is statistically the same as an AHI of 0." They probably could have pulled another close number out of the air just as easily -- 4 or 6. But "five" is a nice round number.

A little off that subject, but related, was this interesting old article with Dr. Colin Sullivan and Dr. David Rapoport discussing:
THE APNEA-HYPOPNEA INDEX: USEFUL OR USELESS?
http://www.pulmonaryreviews.com/sep02/p ... Index.html

I agree for the most part with Sullivan.
Perhaps I'm biased because this is the way I went about diagnosing and treating myself...LOL!
Probably the best indicator of SDB, however, is simply the response to continuous positive airway pressure (CPAP) treatment. “It really is a no-brainer,” Dr. Sullivan remarked, pointing out that CPAP administration is especially easy with the newer devices that automatically set the appropriate amount of positive pressure.

I do agree with this, "The AHI may not be perfect, but it is useful, argued Dr. Rapoport."
I'm just not crazy about where Rapoport draws lines in the sand -- especially the "gray zone" sand.

SDB can probably be ruled out at an AHI of about 10 per hour.

Dr. Rapoport cautioned against over-interpreting the “gray zone” between AHIs of 10 and 20 per hour. “I do not quite know what that means,” he acknowledged.

I'm glad Dr. Rapoport was not diagnosing me or deciding whether CPAP might do me good. When I finally (two years after starting my own treatment) got a full PSG sleep study, my untreated AHI was more than 5, but below the 10 that would "probably rule out" Sleep Disordered Breathing in Rapoport's view.

I like the way I've felt like a morning person since "trying" CPAP five years ago and continuing it ever since. I also like being a wide awake driver. I think Dr. Sullivan would approve.

[elader]

getting back to the original topic, after several months of data with the APAP, I definitely have a sweet spot of about 10cM in terms of AHI. I am virtually always at 2.5-4.0 AHI at 10cM. If I use the APAP as an APAP and set a range of 9-12, my AHI at 11 -12 are always (ALWAYS) higher than at 10.0 - usually 6-7.

No idea why, but it's good enough data for me to stick with 10cM.

[SheZAAM!]

Thanks Elader. I think I'll stick with my 9cm.

[track]

If someone woke you up 14 times per night, how would you feel the next day? Why don't you try it and let us know how rested you feel after a couple weeks of that.

Who says a person is awakened every time they have a HI. I don't recall ever reading that every HI awakens a person..let alone to the same degree as having someone come in and shake you until you are awake and cognizant of being awake. The whole notion or suggestion seems pretty absurd to me.

[Hawthorne]

You are not awakened,with an H or an OA for that matter, especially when you are on xpap. You are "roused" from a sleep level to a "less deep" sleep level but don't actually wake up.

Without cpap, you may not be fully awakened either (you may become fully awakened though to begin breathing again) but, again,just move to a less deep level of sleep so you can overcome the event.

The more this happens during the night, the more tired a person will be during the day.


I don't think I'm explaining that very well but I tried to say how I understand it!!

[track]

I think you have made it clear that having an HI event is not the same as having a person come in the room and wake you up...and I agree.

[DoriC]

Hawthorne, you described exactly how my husband slept before xpap, take it from someone who watched him sleep that way for a long time. First, heavy snoring, then an event, semi-arousal maybe but still asleep, tossing and turning, leg movements, more snoring, another event, etc. I was sure he had to be awake but when I would call him, he was asleep and didn't respond. He did awaken 3-4x a night to use the bathroom. All that has disappeared.