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correlation between apnea and sleep cycle?
#1
I have noticed that my AHI varies considerably during the night. Sometimes it is over 40 and sometimes it quiets down to nearly 0. To remove the effects of APAP pressure variation, I set my machine to CPAP mode and put it on the lowest setting (4.0) for one night.

If there is any larger pattern it seems that I have fewer events towards morning.

Is this common? What might cause this kind of variation? I'm thinking of some possibilities: Sleep Position, Sleep Cycle, others?

When I am on APAP, I don't see much relationship between pressure and AHI - the events seem to continue relatively constantly for some period even though the pressure has, say doubled, tripled, or more.

Any thoughts would be appreciated.

thanks.
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#2
(01-03-2016, 11:10 AM)myapneas Wrote: I have noticed that my AHI varies considerably during the night. Sometimes it is over 40 and sometimes it quiets down to nearly 0. To remove the effects of APAP pressure variation, I set my machine to CPAP mode and put it on the lowest setting (4.0) for one night.

If there is any larger pattern it seems that I have fewer events towards morning.

Is this common? What might cause this kind of variation? I'm thinking of some possibilities: Sleep Position, Sleep Cycle, others?

When I am on APAP, I don't see much relationship between pressure and AHI - the events seem to continue relatively constantly for some period even though the pressure has, say doubled, tripled, or more.

Any thoughts would be appreciated.

thanks.

Your experiment resulted in you not having therapy for that night.
When going from APAP to CPAP, the pressure is generally set at what the APAP has established as the 90th percentile pressure.


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#3
"Your experiment resulted in you not having therapy for that night."

Yes, I'm aware of that. I wanted to see what the system reported without therapy. I failed two on-site sleep studies because I couldn't sleep. Because there was no titration results, my MD set the pressure range wide open (4.0 to 20.0), but there was very little information to see if it was helping, or how much.

My diagnosis was based on an at-home study where I only slept for about an hour, and which reported an AHI of 40, but I've noticed that my numbers jump all over for very short sleep periods when I'm using the APAP, so I didn't particularly trust the original at-home study numbers.

If it wasn't clear in the original post, I'm now trying to find out (1) why the AHI varies so much over time without therapy, and (2) why I don't typically see a reduction in events as pressure increases during therapy. Taken together, the "AHI varies a great deal without therapy" and "AHI doesn't respond much in the short term to pressure changes" make me wonder if the treatment is having any effect at all.
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#4
Your event density varies through the night (untreated) due to the things that you mentioned. Position and Sleep Stage.

A better test to determine if higher pressure might reduce events would be to select a pressure 1 or 2 centimeters higher than your average 95% pressure and use that as a constant pressure all night long. Compare results to non-treated and APAP. Your lack of apparent benefit from APAP might be from a range setting that is not optimum.

Best Regards,

PaytonA

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PaytonA passed away in September 2017
Click HERE to read his Memorial Thread

~ Rest in Peace ~
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#5
OK let's dig into what's going on. To begin, exactly which ResMed APAP do you have?
Then, using software, what types of apnea are you recording.
If pressure does not reduce apnea, then they may be central apneas. And if central, you may not have the proper machine to deal with them.
You can post a screenshot from SleepyHead by attachment if you get the size under 300KB.


Admin Note:
JustMongo passed away in August 2017
Click HERE to read his Memorial Thread

~ Rest in Peace ~
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#6
(01-03-2016, 12:53 PM)PaytonA Wrote: A better test to determine if higher pressure might reduce events would be to select a pressure 1 or 2 centimeters higher than your average 95% pressure and use that as a constant pressure all night long. Compare results to non-treated and APAP. Your lack of apparent benefit from APAP might be from a range setting that is not optimum.

Thanks for the reply! My 90% pressure is 15.70. I suspect my 95% pressure would be around 18, but Sleepyhead doesn't seem to provide that number for more than a single night.

I don't believe I could fall asleep after setting the pressure at a constant 18 or 19.

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#7
(01-03-2016, 01:23 PM)justMongo Wrote: OK let's dig into what's going on. To begin, exactly which ResMed APAP do you have?
Then, using software, what types of apnea are you recording.

First, thanks very much for the reply.

I have a ResMed AirSense 10 AutoSet.
I get mostly hypopnias. With the "no therapy" test, I got only one CA, but sometimes I get more at higher pressures. Still, the larger problem is the hypopnea, which I assume are obstructive, but I'm unsure. I also sometimes get a lot of RERA.

I'm attempting to post two attachments, one (#2017) from the 'no therapy' night (4 CPAP), the other (#2018) from a prescribed 4-20 pressure autoset night. Both are short, because that's how my sleeping is. On the no-therapy night, there are many RERA. The other night was a relatively 'uneventful' session overall. It also is more suggestive of positive results at the highest level (20) than most of my graphs.

       
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#8
I have been trying to acclimate to my to the treatment for sleep apnea for more than 6 months. With the help of all the people from this board, I am doing much better! There are still good nights and bad nights, but my AHI on good nights range from 8-11 down from 40. I have noticed a consistent pattern between 4 and 5 am,my numbers always go up with AHI;s in the 40's and increase in hypoxia events. Leaks are at a minimum. I have a Phillips respironics auto set at 10.5 to 20 with a 5 min ramp at 8.5. I use a nasal mask. The settings have been working for me unless allergies hit. I have wondered about what happens between 4 and 5, REM??? I don't remember if I dream and thought about trying a split session, but I am doing so much better, I hate to wake up and try to go back to sleep. Perhaps the occurrences are idiosyncratic?
Calliopy
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#9
"I have a ResMed AirSense 10 AutoSet." Please edit your profile; that's where people will look to see what machine you have.

Hypos are generally obstructive in nature; but can be central. One would have to zero in on the flow rate data around a hypo to figure out what's going on. Your scored CAs may be pressure induced; and might abate with time. Interesting is the "run-away" pressure at just after 04:30. You had a CA to which the machine should not raise pressure, then two hypos. Earlier you had more hypos; but machine pressure ran around ~13 cm-H2O.

What's the history of this machine: New? Used? How long have you had it; and how long have you been using it?
I am concerned that the machine may be either defective; or you may suffer from mixed apnea which is not well treated by either a CPAP or Autoset.

Was the machine dispensed after a sleep study evaluated your apnea?
Did you have a sleep study?
What does the summary of the sleep study say about type of apnea, suggested therapy mode, pressure...

Can you revisit this with a sleep physician?


Admin Note:
JustMongo passed away in August 2017
Click HERE to read his Memorial Thread

~ Rest in Peace ~
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#10
Quote:"I have a ResMed AirSense 10 AutoSet." Please edit your profile; that's where people will look to see what machine you have.
Done. thanks.

Quote:Interesting is the "run-away" pressure at just after 04:30. You had a CA to which the machine should not raise pressure, then two hypos. Earlier you had more hypos; but machine pressure ran around ~13 cm-H2O.

What's the history of this machine: New? Used? How long have you had it; and how long have you been using it?

I wondered about this myself. The machine was issued by a service contracted by my sleep specialist. I've been using it less than a month, but it could be used.

Quote:Did you have a sleep study?

I had an at-home study. I couldn't sleep enough in the on-site study to get any results.

Quote:What does the summary of the sleep study say about type of apnea, suggested therapy mode, pressure...

I never got the summary Sad. I'll have to ask for it.

Quote:Can you revisit this with a sleep physician?

Yes. I plan to call one tomorrow. I hadn't realized until this week that the person I've been working with at my hospital sleep center is an NP and not an MD.

Thank you again for your time and assistance.
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