Actual hours of sleep

And wouldn't an hour and a half put you in REM sleep on many occasions??? 90 minute segments could be one sleep cycle each??

So if I understand correctly what everyone is saying, AHI readings are completely unreliable since one doesn't know how long one has slept. The AHI is calculated by the number of events divided by the hours of therapy which can be completely different from the hours of sleep. For the AHI to be acurate, one would have to know the exact number of hours slept.

pine3874 wrote:So if I understand correctly what everyone is saying, AHI readings are completely unreliable since one doesn't know how long one has slept. The AHI is calculated by the number of events divided by the hours of therapy which can be completely diverent from the hours of sleep. For the AHI to be acurate, one would have to know the exact number of hours slept.

This is one reason why a PSG is superior to the data from your machine, but the problem isn't really what to divide by. Even if you knew how many hours you slept, some of the events will be scored while you are awake. You can even score OAs while awake. Swallowing repeatedly will do that. And if you're stuffed up enough and hold your breath, the machine might decide you were trying to breathe and couldn't. It has no way to monitor your diaphragm, so it can't tell for sure.

One thing you can do is look at your data carefully, and eliminate centrals that happen when you were probably awake. But this is tricky, and it's often hard to tell when you were awake and when you weren't.

When your sleep is badly fragmented, your AHI will be less accurate. But as you start going to sleep faster and sleeping longer, your AHI will become more meaningful. For now you might just look at your data breath by breath and make sure that obstructive events aren't waking you up. If that's not it, try to figure out what is waking you up. Hopefully as you get used to wearing the mask and fine tune your therapy, your sleep will become less fragmented, and you'll start feeling better. Along in there somewhere, your AHI will start to make more sense.

pine3874 wrote:So if I understand correctly what everyone is saying, AHI readings are completely unreliable since one doesn't know how long one has slept. The AHI is calculated by the number of events divided by the hours of therapy which can be completely different from the hours of sleep. For the AHI to be acurate, one would have to know the exact number of hours slept

No, I don't think that the AHI readings are unreliable.
If my AHI is less than 2 (or the generally accepted standard of 5) it doesn't really matter if I happened to be awake with a toss or turn for a couple of minutes or more or even half the night. There is nothing to dissect.

Now if there is an usually high cluster of events at sleep onset or during a known break during the night, then yes something to dissect and try to figure out what might be going on.

If you are only satisfied with "exact" and "perfect" then you are going to have a tough time because there are very rare absolute values in sleep apnea treatment. There is almost always some sort of variable mixed in.

pine3874 wrote:So if I understand correctly what everyone is saying, AHI readings are completely unreliable since one doesn't know how long one has slept. The AHI is calculated by the number of events divided by the hours of therapy which can be completely different from the hours of sleep. For the AHI to be acurate, one would have to know the exact number of hours slept.

Well, if the AHI is low, you know things are good.

If AHI is high, you can't really be sure and need to investigate. If AHI is high, you may need to make a note of when you're asleep and look at the data. If you are recording "events" when you're awake, I think you will almost never have "severe" events when you look at them on the flow waveforms.

Even if you have a "high" AHI number while asleep, I think you need to look at the waveforms and look at how severe they are. Lots of things that meet the theoretical definition of "apnea" according to the machine don't worry me unless they're too numerous.

I also think that AHI numbers will not tend to be very high even if you are awake.

AHI also has a lot to do with qualifying for insurance. If you get false high readings, you may qualify for something you theoretically shouldn't. That's better than not qualifying for something you should qualify for.