Sleep Study #4 (Now I'm REALLY puzzled...)

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Darth Lady
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Sleep Study #4 (Now I'm REALLY puzzled...)

Post by Darth Lady » Sun May 03, 2015 4:24 pm

I decided to make a new thread of this because it raises a different question. Anyone dedicated (or crazy?) enough to want the background can find it here: viewtopic.php?f=1&t=105003&st=0&sk=t&sd=a.

Sleep Study No. 4 was a retitration study. Coming out of it, the only changes were to decrease the minimum EPAP from 10 to 6 (does this even make sense?) and to increase max PS from 15 to 19.
Max EPAP remain at 15; Min IPAP at 10, Max IPAP at 25.

This PS change really has me puzzled (not that I have that great an understanding of PS anyway). At home, PS is never over 5 normally.

Which brings me to my next question. When I first got Dartha, for the first few nights (three to be exact), my graphs looked like this (all that "fur" at the top is machine-timed breaths) :
Image

The night after that shot, it looked like this (mostly doing my own breathing now):
Image

It's pretty much looked like this ever since. Pressures overall (and especially PS) became way, way lower way, way suddenly. I'm puzzled because the latest sleep study says I need access to this very high PS of up to 19, when, as I noted, lately it's never over 5 at home (although theoretically it's allowed to go to 15).

What could cause this? Machine malfunction? My AHI doesn't seem to be suffering, although overall my sleep is crap (I've given up trying to figure that out for now; probably "just" menopause). Could Dartha (or, hey, my body?) have learned, overnight, that I didn't need pressures that high, and if so, why would a sleep study say that I do?

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Re: Sleep Study #4 (Now I'm REALLY puzzled...)

Post by JDS74 » Sun May 03, 2015 4:55 pm

Why the change of EPAP min from 10 to 6 - who knows.
The change from PS max from 15 to 19 is to preserve the pressure range in case the machine needs to breathe for you.
That setting allows the machine to drop to EPAP min of 6 cm H2O and switch to IPAP of 25 in case you need it.

so, 10 + 15 = 25 and 6 + 19 = 25 = max IPAP.

That's the way my machine is set up. Although I have noticed that my PTB% is in the high 90's with a EPAP of 14.5 (EPAP min + PS min) and in the low 70's with an EPAP of 10.

Wish my numbers looked like yours. My AHI hovers in the 5 to 10 ranges always with lots and lots of hypopneas.

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Re: Sleep Study #4 (Now I'm REALLY puzzled...)

Post by Darth Lady » Sun May 03, 2015 5:10 pm

Wow. I'm sorry to hear that about your AHI.

Thanks for explaining the ASV arithmetic. This whole mess came out of a WatchPAT study that happened because I felt like crap even with treatment. Said study said that my AHI was still over 12. Dartha begged to differ (all in the thread in my first post). Seems Dartha was right - all this legerdemain and they aren't really changing much of anything!

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Re: Sleep Study #4 (Now I'm REALLY puzzled...)

Post by robysue » Sun May 03, 2015 5:24 pm

Darth Lady,

Please correct me if I'm wrong, but your original diagnosis involves central apnea of some sort, doesn't it?
Darth Lady wrote: Sleep Study No. 4 was a retitration study. Coming out of it, the only changes were to decrease the minimum EPAP from 10 to 6 (does this even make sense?) and to increase max PS from 15 to 19.
Max EPAP remain at 15; Min IPAP at 10, Max IPAP at 25.
By decreasing the min EPAP, they may be trying to make sure that you are less likely to blow off too much CO2. The trigger for inhalations is the CO2 level in your blood, and when too much CO2 is exhaled, that can cause problems with getting the normal sleep breathing pattern established. Even when we don't have a mask on our face, there's a certain amount of "dead space" in our respiratory system that allows us to rebreathe a tiny bit of the CO2 we normally exhale. When a vented CPAP mask is doing too good of a job at venting the CO2 out of the mask, it can under some circumstances, lead to the person blowing off too much CO2. Lowering the EPAP pressure lowers the flow rate of air through the mask and reduces the expected exhaust flow rate. And that may be what your sleep doc is wanting to do.

The max PS was increased to 19 so that your IPAP can theoretically go all the way to 15 even if the EPAP remains at 6. In other words, right now the doc doesn't want to put a very tight upper restriction on the max IPAP. For whatever reason, he wants the machine to be allowed to get to IPAP = 25 if it wants to go there, and he wants that to be able to happen even if the EPAP is still sitting at it's minimum setting of 6cm. 25 = 6 + 19, so if min EPAP = 6 and the doc wants to allow the machine to get to IPAP = 25 if it wants to, then max PS has to be set to 19.
This PS change really has me puzzled (not that I have that great an understanding of PS anyway). At home, PS is never over 5 normally.
For reasons that I don't know or understand, your doc wants to allow the machine to reach an IPAP = 25 if the machine thinks you need that much IPAP even when the EPAP is at the minimum setting. And the max PS has to be set so that: Max IPAP = Min EPAP + Max PS.

If Max IPAP = 25 and Min EPAP = 6, then Max PS has to be set to 19 in order for the machine to theoretically use IPAP = 25 and EPAP = 6. The fact that your machine never reaches that theoretical limit is largely irrelevant.

The second night of posted data certainly looks good. And you say it's typical of what you usually see now. But as I recall your WatchPAT data did NOT look this good and the WatchPAT data is what lead to the 4th sleep study?
as I noted, lately it's [PS] never over 5 at home (although theoretically it's [PS] allowed to go to 15).
With your current settings, your IPAP never gets to be much more than 15 and your min EPAP = 10. Hence the largest difference between IPAP and EPAP is never much more than 5cm, and that's why your PS stays around or below 5. If your IPAP were getting higher with EPAP staying at 10, then the PS numbers would also get larger.
What could cause this? Machine malfunction? My AHI doesn't seem to be suffering, although overall my sleep is crap (I've given up trying to figure that out for now; probably "just" menopause). Could Dartha (or, hey, my body?) have learned, overnight, that I didn't need pressures that high, and if so, why would a sleep study say that I do?
The fact that the max IPAP pressure is SET to 25 and the max PS is SET to allow IPAP to go as high as 25 when the EPAP is at your minimum setting does NOT mean that your machine will ever see the need to make the IPAP go that high when the EPAP is at its minimum.

The question you may want to ask the doctor is: Why set the Max IPAP much higher than my machine is ever willing to go? If the machine never increases the IPAP much above 16 and why should we set the Max IPAP=25?

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Re: Sleep Study #4 (Now I'm REALLY puzzled...)

Post by Darth Lady » Sun May 03, 2015 5:59 pm

robysue wrote:Darth Lady,

Please correct me if I'm wrong, but your original diagnosis involves central apnea of some sort, doesn't it?
Darth Lady wrote: Sleep Study No. 4 was a retitration study. Coming out of it, the only changes were to decrease the minimum EPAP from 10 to 6 (does this even make sense?) and to increase max PS from 15 to 19.
Max EPAP remain at 15; Min IPAP at 10, Max IPAP at 25.
By decreasing the min EPAP, they may be trying to make sure that you are less likely to blow off too much CO2. The trigger for inhalations is the CO2 level in your blood, and when too much CO2 is exhaled, that can cause problems with getting the normal sleep breathing pattern established. Even when we don't have a mask on our face, there's a certain amount of "dead space" in our respiratory system that allows us to rebreathe a tiny bit of the CO2 we normally exhale. When a vented CPAP mask is doing too good of a job at venting the CO2 out of the mask, it can under some circumstances, lead to the person blowing off too much CO2. Lowering the EPAP pressure lowers the flow rate of air through the mask and reduces the expected exhaust flow rate. And that may be what your sleep doc is wanting to do.
I have complex sleep apnea. I failed CPAP and then failed BiPAP because of centrals.

It's just weird that for the first three days the ASV did practically all my breathing for me, and then since Day 4 I've had hardly any machine-triggered breaths at all. The change was sudden, extremely noticeable and not because of any changes to the settings. But since it hasn't made any difference to my AHI, I'll just shrug it off as one of those things. If your theory is correct, though, the doc is trying to correct something that isn't really an issue - I still have very few machine-triggered breaths.

BTW I have read your insomnia threads with interest as this is increasingly an issue for me. There appears to be no apnea-related reason for it, but my sleep has just gone to hell since I started treatment. I've started to dread the nighttime, because I know I'll be up by 2 a.m. with night sweat after night sweat, unable to find a comfortable position. But such is life.

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Re: Sleep Study #4 (Now I'm REALLY puzzled...)

Post by JDS74 » Sun May 03, 2015 6:52 pm

I've had a couple of days where my ASV kicked in and breathed for me for two hour stretches - just sitting there switching between 10 and 25 breath by breath for the whole two hours. Haven't had any of those recently .

Do you have any of the night sweat symptoms during the day? I do that about every hour all day and all night.. Still looking for a cause . Mine started eleven years ago and the docs all say the same thing - no clue as to cause.

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Re: Sleep Study #4 (Now I'm REALLY puzzled...)

Post by Darth Lady » Sun May 03, 2015 6:57 pm

I do get hot flashes during the day. Unfortunately, I seem to get more of them at night - although perhaps the misery is causing me to overestimate... And I wish I could tell whether the impending sweats wake me up, or whether I wake up and then have a sweat, which is how I perceive it as happening.

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Re: Sleep Study #4 (Now I'm REALLY puzzled...)

Post by Uncle Flapp » Sun May 03, 2015 7:53 pm

Darth Lady wrote: I have complex sleep apnea. I failed CPAP and then failed BiPAP because of centrals.

It's just weird that for the first three days the ASV did practically all my breathing for me, and then since Day 4 I've had hardly any machine-triggered breaths at all.
No advice to give but would like to mention that I had a very similar experience. I went the same route getting to ASV and for the first week or two, my patient triggered breaths were below 40%. Now they are usually in the 80's.
Darth Lady wrote:I do get hot flashes during the day.
Ok, well, I haven't had that experience.

- Flappy

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Re: Sleep Study #4 (Now I'm REALLY puzzled...)

Post by Darth Lady » Sun May 03, 2015 8:20 pm

Uncle Flapp wrote:
Darth Lady wrote:I do get hot flashes during the day.
Ok, well, I haven't had that experience.

- Flappy
My husband theorizes it's called "menopause" because it causes us women to pause from men!
Bleagh.

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Re: Sleep Study #4 (Now I'm REALLY puzzled...)-Update

Post by Darth Lady » Wed May 06, 2015 9:17 am

So the DME got the new prescription from my doc and dutifully set min EPAP to 6, PS to 19.

And I HATED it!! . Felt like I got no air at all, a sensation I remember from the sleep study, waking up and gasping and then using the usual techniques I use to get an ASV to supply more pressure, like not breathing for a few seconds. Surprisingly, the tech didn't make anything of that. Just the usual "patient tolerated these settings well."

Gee, no one asked me how I felt about the whole thing.

So I did what any (or most) cpaptalk forum members would do - Sweetieboo and I promptly changed the settings back to min EPAP 10, PS 15 . Had a great night . AHI of 0 . Had to take a Vicodin because my minor surgical wound was acting up, but even so, much less waking than usual (I'm betting pain is a big part of my sleep problems, at this point).

Out of politeness, I'll write the doc and tell her what we did.

So, the upshot of "WatchPAT says your RDI is 22 and your AHI is 13 so we have to retitrate" was...a pressure drop . That I hated . Maybe therapeutically I could do just as well at 6 (I've lost at least 30 pounds since the diagnostic study, including a lot of fat from my neck area, for one thing), but my machine was right - I was doing pretty damn well with 10 as the base number .

Whatever my remaining issue(s) is/are, it seems to not be SDB (you're right, Morbius! ). So if it ain't broke, don't fix it...

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Re: Sleep Study #4 (Now I'm REALLY puzzled...)

Post by postitnote » Wed May 06, 2015 9:35 am

Darth Lady wrote:
Uncle Flapp wrote:
Darth Lady wrote:I do get hot flashes during the day.
Ok, well, I haven't had that experience.

- Flappy
My husband theorizes it's called "menopause" because it causes us women to pause from men!
Bleagh.
Our husbands could be related!
What does a hot flash feel like? I still don't think I've had any.
Morbius, are you bored?

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Re: Sleep Study #4 (Now I'm REALLY puzzled...)

Post by Darth Lady » Wed May 06, 2015 9:53 am

postitnote wrote:
Darth Lady wrote:
Uncle Flapp wrote:
Darth Lady wrote:I do get hot flashes during the day.
Ok, well, I haven't had that experience.

- Flappy
My husband theorizes it's called "menopause" because it causes us women to pause from men!
Bleagh.
Our husbands could be related!
What does a hot flash feel like? I still don't think I've had any.
Believe me, you'll know one when you feel it. You kind of go like this: . Sometimes there's a headache. Then you sweat. It's like Scotty (or maybe Morbius? ) beamed you into a sauna somewhere. I spend the night hogging the blankets, throwing off the blankets, hogging the blankets, throwing off the blankets, etc., etc.

Real fun with stuff all over your head, because inch for inch, you lose more heat from there than anywhere else.

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Re: Sleep Study #4 (Now I'm REALLY puzzled...)

Post by BlackSpinner » Wed May 06, 2015 10:35 am

Believe me, you'll know one when you feel it.
Mine always felt a bit like ants walking over my skin before the heat came on. The heat seems to be mainly external unlike a fever. I haven't worn a high necked garment since it started many years ago.

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Re: Sleep Study #4 (Now I'm REALLY puzzled...)

Post by postitnote » Wed May 06, 2015 12:42 pm

Darth Lady wrote:

Believe me, you'll know one when you feel it. You kind of go like this: . Sometimes there's a headache. Then you sweat. It's like Scotty (or maybe Morbius? ) beamed you into a sauna somewhere. I spend the night hogging the blankets, throwing off the blankets, hogging the blankets, throwing off the blankets, etc., etc.

Real fun with stuff all over your head, because inch for inch, you lose more heat from there than anywhere else.
Wow! I had a friend who was like that in her early 40's. She would drip from her head. I really thought that was an isolated incident as she was sick with so many things before she passed. Our waterbed is pretty warm so I'm not much for blankets even in winter. Geeze I hope I miss out on the flashes. I never got cramps so maybe.
BlackSpinner wrote:
Mine always felt a bit like ants walking over my skin before the heat came on. The heat seems to be mainly external unlike a fever. I haven't worn a high necked garment since it started many years ago.

Whoa, ants? Since it started many years ago? How long will it last?
Morbius, are you bored?

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Re: Sleep Study #4 (Now I'm REALLY puzzled...)

Post by Darth Lady » Wed May 06, 2015 2:00 pm

Yeah, I'd forgotten about the ants . For me, it's like little tiny stings as I start to sweat.

I read somewhere that it can last as much as twenty years . But when I mentioned that to my GYN, she snapped that it absolutely wasn't true. I guess it really varies from woman to woman. Here we go again!

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