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+--- Thread: AHI even when awake? (/Thread-AHI-even-when-awake)
AHI even when awake? - novatom - 01-06-2015
I'm entering into my second week of therapy but I'm a little confused about my results. The first couple days I got very little sleep and my AHI was low, but as I started getting more sleep and getting used to my mask, my AHI level went up.
That made sense but last night I was awake from about 3 AM until I got up about 5:45, and yet, according to Sleepyhead, I had a lot of AHI (incidents? what's the proper verbiage? I'm still learning the lingo). Last night was 17.10, not good.
Why would I have AHI while I'm awake?
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RE: AHI even when awake? - eseedhouse - 01-06-2015
(01-06-2015, 06:33 PM)novatom Wrote: Why would I have AHI while I'm awake?
Insomniacs often get periods of sleep even when they think they are awake. Your machine, of course, does not know anything about your state of consciousness beyond what it can infer from your breathing pattern.
My guess (and it's only that) is that you may have dozed off for a couple of minutes without realizing it and that's when your AHI happened. But if you just stop breathing for awhile even while awake your machine wouldn't know that you were actually awake, it would only know that you stopped breathing for awhile.
RE: AHI even when awake? - quiescence at last - 01-06-2015
ok. that's a bunch. AHI is not the amount, but a number expressing (total # events)/(total hours). So, you could have a very short sleep and get a high AHI.
So, you were awake, and your OA score during that period is extra low, that is expected. What the CA and H are during that time could be truly "slow or halted breathing" that the machine thinks looks a lot like same type of breathing it is supposed to track during your sleep. The machine does not have a "this guy's asleep" sensor.
Suggest you zoom the chart to include only the time you were asleep. Then, look at the heading of the plot, it will show the AHI calculated for the period that is visible. - it still looks like it will be high, though.
Did you have acid indigestion? Anyway I agree with seed you probably actually dozed off.
Good luck as you continue!
RE: AHI even when awake? - vsheline - 01-06-2015
(01-06-2015, 06:33 PM)novatom Wrote: I'm entering into my second week of therapy ... last night I was awake from about 3 AM until I got up about 5:45, and yet, according to Sleepyhead, I had a lot of AHI (incidents? what's the proper verbiage? I'm still learning the lingo). Last night was 17.10, not good.
Why would I have AHI while I'm awake?
Hi novatom,
It is not unusual for us to have some Periodic Breathing or Central (Clear Airway) Apneas and hypopneas when falling asleep or awakening. If our machine reports these "events" during periods when we know we were awake, we can ignore these events when calculating our adjusted AHI.
Also, a few people have these Central events while wide awake, especially when concentrating strongly on something they are doing or watching.
Also, it is not uncommon for us to get extra Central Apneas in the first few days or weeks of CPAP therapy, and these usually gradually decrease to an insignificant level within the first few months of therapy as our system gradually becomes accustomed to the therapy.
If after a couple months of therapy your Central Apnea Index (average number of Central Apneas per hour) is still not less than 5 per hour, you might do better with an upgraded "ASV" machine (Adaptive Servo Ventilator). If that turns out to be the case, your doctor may prescribe an overnight ASV titration and then prescribe an ASV machine.
Take care,
--- Vaughn
RE: AHI even when awake? - Sleeprider - 01-06-2015
You can zoom in on some of those events and try to get a handle on what's going on and the duration of the CA and OA events. It might be interesting. Your overall AHI is over 10, and that's not so good for treatment. If that continues another week, I strongly recommend increasing pressure and see if you can clear up some of that. Your image cuts off leak information which might be useful, and the pressure information is useless since it never changes. You can download a manual for your machine here Download Link.
RE: AHI even when awake? - vsheline - 01-07-2015
(01-06-2015, 11:13 PM)Sleeprider Wrote: Your overall AHI is over 10, and that's not so good for treatment. If that continues another week, I strongly recommend increasing pressure and see if you can clear up some of that.
Hi novatom,
Raising the pressure tends to lower the number of obstructive events we get, but also it may tend to increase the number of Central events we get.
For a few people, the Central Apnea Index may get quickly worse if the pressure settings are raised, so caution is always advisable when considering whether the pressure should be raised when the patient is already having an excessive number of CA events. (I think a CAI of 2.5 or less is not excessive.)
If after a few more weeks it still looks like the majority of your apneas are Central in type, then I would suggest caution when considering whether to raise the pressure settings, in order to reduce the number of obstructive events. I would suggest not raising the pressure faster than 0.5 cm H2O per couple weeks.
Take care,
--- Vaughn
RE: AHI even when awake? - novatom - 01-07-2015
Thanks everyone for your advice. I'm still trying to learn the proper lingo and descriptions so forgive me if I sound confused sometimes.
My machine was set by the clinic to 6 so I would have to get them to change it. I go in for follow up on Jan. 20 so I'll ask them then. Of course, they just gave me the machine along with instructions on how to set it up and maintain it. I think this therapy period (4 weeks) is just to see how I react to the machine. They gave me no instructions or suggestions whatsoever on how to analyze data.
Any suggestions on what I should ask them?
I should add that the leak rate has been very low. I don't have it in front of me now, but I have been pleased with that data since it shows that I can adapt to the nasal pillows and not have to go full mask.
Data or not, I am feeling better and I notice that I have more energy. Last night I probably slept off and on for more than 6 hours, which is higher than my usual average and, more importantly, I was able to go back to sleep after waking up. This was not the case when I was in the worst throes of my insomnia. I would wake up after 3-4 hours of sleep and never get back to sleep.
RE: AHI even when awake? - quiescence at last - 01-07-2015
good for you. glad you are feeling rested and alert.
you'll probably get blank starring if you ask them anything regarding waveform shapes and types of apnea, anything beyond AHI and # of Hrs Used (Compliance) doesn't usually interest them.