why am i prescribed at this level? Does apap help w/ rera?

[neillebo]

Here is my problem, as I just got back a more detailed sleep study, things just dont make sense.

They prescribed a pressure of 9 . At 9, i showed a higher AHI of 7.6/ Vs an AHI of 1.7 at a lower pressure of 8!!!!!! The reason, i am guessing, is that at 8, even though a much lower AHI, i had 19 Rera/hr! At my prescribed level of 9, even though the AHI jumps up to 7.6, i had only 13 rera events/hour. Both had 92% oxygen saturation.

Why would they want me to have a higher AHI at 9 vs 8 pressure. Seems to me, unless i am missing something, that at 8 i have total resp events (ah plus rera) of 21 and at MY PRESCRIBED PRessure, i have 23 total events (and with markedly more apneas to boot) ???? they are trading off more apenas/hypop for fewer rereas, but i still total more of both.. surely the apnea/hypo are worse for me than the reras.. even so, if i was reading this i would prescribe 8. My doct only tells me that "we know what we're doing and will talke about it in a few weeks when she can make money off of an office visit with me live. can anyone make sense of this...

any my other main question is:

Does APAP react at all to rera? they are still respiratory arousals, just not complete cessation of breathing nor the 50% hypopnea level decrease.. but is it that scientific? ... Looking at my results, the machine would clearly titrate me at 8.. Had 9 shown far fewer reras and total resp events, i am sure i would have preferred to go to that.. but i dont get it..

anyone able to shed any light on the crazy results and what the apap machine does with reras?

[rested gal]

Sleep stage and position can have a bearing on what pressure a person needs.

The "regular" events (apneas, hypopneas) hit hardest for most people when they are on their back and/or are in REM sleep.

Maybe either/both of those things (supine position, REM) were the case when you were finally at a pressure of 9 but not the case at pressure of 8?

At any rate, hopefully you'll have an autopap soon and can let the machine handle what pressure you actually do need, when you need it.

[neillebo]

Thanks. Here is what might interest you. I slept roughly 1/3 1/3 1/3 supine/right/left during original test.. ALL of my apnea/hypop were while supine.. i had ZERO on left and right so although my sleep study ahi was 40.8, it was really 112.4 supine/0 left/0 right (all the more reason to prescribe apap ).. HOWEVER, for my titration study i was on my back 100% of the time.. so, yes, the cpap has had a major impact when looking at it that way. of course, i normally dont sleep all night on my back (1/3 1/3 1/3 sounds right) so the 9 level already seems like overkill...

ps i did get no rem during study, but did get 33 minutes of rem during titration. i do know that i was titrated at 9 when i was in Rem and, of course in my case, supine.

that said, can you see why 9 would have been prescribed over 8, given the first post and also, since i have alot of reras, does the machine notice/take care of those?

_________________

CPAPopedia Keywords Contained In This Post (Click For Definition): Titration, CPAP, AHI, APAP

[rested gal]

i do know that i was titrated at 9 when i was in Rem and, of course in my case, supine.

that said, can you see why 9 would have been prescribed over 8, given the first post

Yes, I can see why 9 would have been prescribed over 8. You said you were on your back (supine) throughout the entire titration. If you were not in REM during the pressure of 8, but WERE in REM (as you said you were) during the pressure of 9, I can see where there could have been more events (apneas/hypopneas) popping up suddenly during pressure of 9. For most people the events do hit hardest and heaviest during REM.

Actually, I'm surprised they didn't prescribe 10 for you even though that pressure may not have been tried during the titration. Pressure of 9 didn't knock all the apneas/hypopneas out apparently -- at least not while you were in REM. I suppose they ran out of time to try any further?

and also, since i have alot of reras, does the machine notice/take care of those?

RERA = Respiratory Effort Related Arousal. A lessened airflow, but not "bad enough" to fit the definition of an hypopnea which requires a certain percentage (4%?) drop in SpO2 along with a certain percentage reduction in airflow.

The machines can't identify arousals -- gotta have those PSG wires attached to the head monitoring brain waves to see arousals. And have to have the belts around chest and abdomen to see respiratory effort. But, the autopaps do take preemptive action if they see reduction in airflow ("flow limitation.") So that should help. You won't see anything about arousals or respiratory effort on the cpap software, though.

The closest you'll get even a rough glimpse of that will be if "flow limitations" sneak through and are marked on the cpap's data results. But not all flow limitations cause "arousals." The ones that don't cause an arousal are nothing to worry about. The autopap and software just can't tell you if each flow limitation it marks actually "did" or "didn't" cause an arousal.

[Perchancetodream]

I would assume that APAP, being a form of CPAP, would effect reras as indicated in this article that I found on: http://www.springerlink.com/content/dmnndnfreldrwb2r/

Effect of CPAP treatment on inspiratory arousal threshold during NREM sleep in OSAS
Journal Sleep and Breathing
Publisher Springer Berlin / Heidelberg
ISSN 1520-9512 (Print) 1522-1709 (Online)
Issue Volume 9, Number 1 / March, 2005
Category Original Article
DOI 10.1007/s11325-005-0002-5
Pages 12-19

Original Article
Effect of CPAP treatment on inspiratory arousal threshold during NREM sleep in OSAS

José Haba-Rubio1, Emilia Sforza, Thomas Weiss1, Carmen Schröder1 and Jean Krieger1, 2 Contact Information
(1) Sleep Disorders Unit, University Hospital, 67091 Strasbourg, France
(2) Clinique Neurologique, CHU-Strasbourg, 67091 Strasbourg, France

Published online: 17 February 2005
Abstract The maximal inspiratory effort recorded at the end of apnea has been considered as an index of arousal threshold in obstructive sleep apnea syndrome (OSAS). Previous investigations have shown that the arousal threshold is higher in patients with OSAS than in normal subjects. The aim of the present study was to investigate the effect of continuous positive airway pressure (CPAP) treatment on the inspiratory-effort-related arousal threshold in patients with OSAS. In ten male patients, 40 episodes of apnea during stage 2 non-REM (NREM) sleep were analyzed. Apnea duration (t), esophageal pressure (Pes) at the first occluded breath (Pes1), the minimum of the three initial Pes swings (Pes min), the maximum of the three final Pes swings (Pes Max), DeltaPes (Pes Max–Pes min), RPes (rate of increase of intrathoracic pressure, DeltaPes/t), n (number of occluded breaths during apnea), DeltaPes/n, n/t, and SaO2 were determined before and after occlusion. These apneic episodes were compared to ten episodes of apnea provoked by a mask occlusion device after 1, 7, 30, and 90 days of CPAP treatment. The therapy resulted in a decrease in the inspiratory-effort-related arousal threshold, as measured by a reduction of Pes Max, without significant changes in apnea duration and apnea-related hypoxemia. Pes1 and DeltaPes/n, which are markers of respiratory drive, significantly decreased between observations. CPAP treatment decreases the inspiratory-effort-related arousal threshold and induces a decrease in ventilatory drive in response to upper airway occlusion.

Susan

[neillebo]

thanks for all of this. well, thank GOODNESS I am returning the cpap and ordered an apap. This way i dont have to obsess (well , not as much ) over the right pressure level. Yes, they did run out of time. It was a split study and they had to wake me at 6am per hospital rules. so, wont be shocked if 10 is the right number. if not, i still like 8 alot better on paper. it does appear i was in rem for all of the 9 titratin, so that is likely why they show 4 OAs instead of the 1 at 8. who knows.. but apap will tell me...

re the RERA, good point. just figured that out also. I just remain concerned that i have VERY Fragmented sleep. i got into almost NO stage III or iv sleep during either part of the split study and very little rem. I do know that i dont like being wired up and am told that the test/titration itself can cause many arousals that wont cause them at home once you get used to the machine. makes sense to me. I just hope that's the case. I did notice that my OAs were gone for all pressure levels starting at 6. .INterestingly enough, it was FOUR Central apneas at pressure of 9 vs 1 central apnea at 8.. Now, i have no clue what it could be.. can pressure affect Central apneas? sorry. I'm a fast learner and almost feel like an MD now (My doc, who is not good cant even answer any of my questions when i spoke with her)

[Perchancetodream]

.INterestingly enough, it was FOUR Central apneas at pressure of 9 vs 1 central apnea at 8.. Now, i have no clue what it could be.. can pressure affect Central apneas? sorry. I'm a fast learner and almost feel like an MD now (My doc, who is not good cant even answer any of my questions when i spoke with her)

Central apneas tend to appear with higher pressures. It is a balancing act to keep the pressure high enough to treat the obstructive apneas without causing CAs.

Susan

[neillebo]

Yes. so I've read.. and from what i understand, if one does get central apneas from presssure that is too high, then they know they are too high.. so if i had ony 1 per hour at 6; 0 at 7; less than 1 at 8 and 6 at 9 (it was 4 in 40 minutes), then why on earth put me at 9. shouldnt i avoid that on top of all else i told you and stick with 8... Will teh machines react to a CA like it is an OA?

[billbolton]

Will teh machines react to a CA like it is an OA?

No, they don't. Treatment of CAs requires a significantly different approach in terms of PAP.

An APAP will give you data but it sounds to me like you will need to be careful what you do with it, as from the information above it appears that you will have to trade off between various SDB issues in terms of selecting the most effective treatment approach, and that is not always a particularly intuitive process!

So, make changes slowly and persist with the effects of a change for a couple of weeks to see how the data plays out logitudinally over that time, rather than making changes over shorter periods.

Cheers,

Bill

[rested gal]

As I understand it, what I'd call "temporary" centrals can pop up in some people's titration when the pressure is changed upward. If that's what was happening, the centrals subside when the body gets used to the new pressure.

"Getting used to it (the new pressure)" can take awhile...could take 20 or 30 minutes. Maybe longer. If the titration was getting a bit rushed toward morning in order to get you up and out of there, that might not have given enough time at those last two pressures to let the centrals go away on their own.

Just one possibility. CSDB is another.

I know a lot of doctors order a "split" study when possible...getting it all over with in one night. I reallllly think it's better to have two-night studies. One whole night for gathering diagnostic data and a separate night for a good titration.

[Guest]

"we know what we're doing and will talke about it in a few weeks.....

I wouldnt be able to handle a doc talking to be like that. If he "knows what he is doing" then he shouldnt take any offense to your curiousity and should explain to you why.

Anyhow sorry that bugs me........Im not sure why but Im sure if there is a good reason many of this board will know, I havent read all the replies soexcuse me if they have already. I also know many people readjust their pressure slightly due to these kind of things. So you can always self compare and see how you feel.