Interpretation-periodic breathing and CA events

stevealive wrote:Last night I ran the machine at 8cm cpap, no ramp, no flex... The OA's did go up, but the centrals were greatly reduced. I'm glad to see the centrals respond.

I hope your sleep doctor suggests an ASV titration. If not, consider getting a different sleep doctor...

BTW, do you happen to have your titration table from your sleep study? That would be the table showing your obstructive and central events that were encountered at the various pressures during your CPAP titration in the lab.

Sleepsurfer- I have Encore Viewer 2.0, so I guess I'm out of luck on the waveform. Originally I was interested in Encore Pro and MyEncore, but I thought Viewer was now the way to go. I had heard there was breath-by breath data, and lately I was wondering where it was. Guess now I know. Are you using Myencore with it? Dare I say it, I have an installer file for Pro I got from a torrent. It seemed to install OK, but I couldn't get MyEncore to work with it, so I deleted it all when I bought Viewer. Now the installer doesn't seem to work, but I might try it on another computer.
-SWS- The only chart in my sleep study that relates to the titration is the one I posted already at the bottom of the sleep study, with the titration written in by hand by the tech. No one in the sleep center would return my calls today, so I hand carried the reports in to them. It is supposed to be on the doctors desk in the morning. I'll let you know....
Thanks everyone.

Last night I ran the machine at 8.5cm cpap, no ramp, no flex.

The OA's are down slightly form the night at 8cm cpap, and the CA's are up just that much. Is this showing a balancing point, where the pressure required to reduce the OA's increases the CA's? At least I had an interval of almost 2 1/2 hours of uninterrupted sleep, and I feel a bit better this morning. Even thought the leak rate is bit up and down, I don't see any correlation with the events. Can anyone comment on that? I just haven't had time to work with taping or a chinstrap.
Hoping to hear from my sleep doctor today. I'll keep you posted.

stevealive wrote: At least I had an interval of almost 2 1/2 hours of uninterrupted sleep, and I feel a bit better this morning. Even thought the leak rate is bit up and down, I don't see any correlation with the events. Can anyone comment on that?

Well, your salient issue does not seem to be a leak-rate or UARS problem IMHO. Your observable pattern strongly hints at CompSAS.

stevealive wrote:Last night I ran the machine at 8.5cm cpap, no ramp, no flex.... The OA's are down slightly form the night at 8cm cpap, and the CA's are up just that much. Is this showing a balancing point, where the pressure required to reduce the OA's increases the CA's?

Yes. That's essentially the crux of the dilemma for CompSAS patients using CPAP or ordinary BiLevel instead of ASV treatment: 1) pressure high enough to adequately address upper airway obstruction induces central dysregulation, while 2) pressure low enough to avoid central dysregulation allows some obstruction. To understand that CPAP balancing-point strategy a little better, you might want to research the CompSAS/CSDB treatment strategy termed "permissive flow limitation" both HERE and on the Internet.

An alternate CPAP treatment strategy for CompSAS---one that has recently emerged in sleep medicine---would be to stay with your most tolerable fixed pressure that favors obstructive treatment versus central. You would experimentally stay with that fixed pressure for a couple months, hoping physiologic adaptation itself gradually diminishes central dysregulation. However, I believe ASV is the currently favored treatment method according to most of the recent CompSAS medical literature I have read to date. Good luck.

you really need to either get another sleep study, or get the software that will show your waveform results. until then we are all just speculating.

your leak rates are highish. at a ppressure of 10, my leak rate is about 24. i use a chin strap and tape. i recommend you do the same. or at least give it a try.

REMEMBER: these machines are not capable of really determining whether you are having a central apnea.

strive for maximum info
good luck

sleepsurfer wrote:REMEMBER: these machines are not capable of really determining whether you are having a central apnea.

Well, recall these machines rely on open-airway detection. Open airway detection methods tend to allow for great central-apnea detection specificity but not-so-good central-apnea detection sensitivity.

sleepsurfer wrote:on my pr system 1 reports my hypopneas tend to turn to centrals as i raise the pressure, however they are not really centrals. the machine just recognizes them as such.

Did you validate that, or is that just an assumption based on this discussion:
viewtopic.php?t=48877#p446779

I read through that thread and saw metaphors and reasoning leading to a consensus opinion vaguely dismissing central apnea detection. But I saw no discussion about WHICH PR1 measurement details TECHNICALLY fall short and specifically WHY they fall short. An open-airway central-apnea detection method that's older (employing cardiac oscillations) entails near 100% specificity but around 60% sensitivity. That means when that open-airway detection method happens to detect a central apnea, that it's almost certainly a central apnea; but that 40% of the central apneas across the patient population will go undetected (thus unidentified or misidentified as obstructive apneas).

Anytime a patient sees PROLIFIC central apneas on their home machine, they should assume they are probably experiencing central apneas IMHO. I definitely agree with the comment that followup with the sleep doctor is required here.

sws,

here is a description i posted a while back of my clear airway apneas (not centrals).

i think what you are experiencing with your central apneas is something i have also encountered. central apneas often occur after an EEG arousal for someone with UARS. that is because when we are unconscious, our breathing is controlled by an involuntary response to carbon dioxide levels in our blood. when you have a smooth even breathing pattern with a sudden arousal which increases your respiration but does not actually awaken you then your brain will sense that carbon dioxide levels are low and will cause a cessation in breathing until the carbon dioxide levels rise again. sometimes this can take many seconds depending on how oxygenated your blood became during the arousal.

so, your apap, which is designed to treat someone with OSA will lower the pressure when it sees a central apnea, when in our case, raising the pressure would be a correct adjustment.

---this is why the gentleman we are trying to help needs more info

Thank you both for the discussion, and the interest to help. I had a big day today, and I'm a bit brain dead now. I'll be better in the morning. I've been studying the topics -SWS recommended. I had hoped to hear from my sleep doctor today, but he didn't call. I'm going to pursue him tomorrow, and follow up more on what you both are saying. Thanks again.

Sleepsurfer, thanks for that followup.

BTW, you described a post-arousal central apnea... UARS patients don't typically present those as prolifically as stevealive presents his central apneas that are associated with high pressure (documented in his PSG). Also, the UARS condition is not associated with that prolific periodic breathing we see above.

Following your discussion and reading the associated posts shows me how experienced you folks are in these matters. Thanks for helping me out. I understand the need for better data-I'll see what I can do about Encore pro. And I'll try to address the leak issues. For now, can I ask a few questions? Here are my charts from last night

This is a slight bit better than the night before, but the pattern is the same. The first four hours had very few events, but corresponded to higher leak rates. My mask indicates a rate about 30 for this pressure. Could the leak rate be affecting the event detection?
-SWS, I read about Permissive Flow Limitation, and the strategy you mentioned to go with a rate that favored the OA, and see if the centrals resolve by adaptation. I wonder if that is what happened before I started with the Auto machine. Initially I ran 8cm cpap for about a month on a compliant-only data machine. After three weeks of feeling I was getting only marginal results, the sleep doc agreed to my request to go to 9cm. (My one recent night at 9cm on the Auto showed reduction in OA, and elevated CA). I did that for about 6 weeks, and eventually I reached a point of feeling better enough to try resuming my typical daily exercise. That felt marvelous, and I accepted an invitation to guide two friends on an 8 day backpacking trip in some remote desert canyon country I've been exploring for years. I had no machine at all, and did marvelously. Despite 100 degree heat, needing to sometimes carry one of their packs up steep inclines, and additional hiking to verify routes in advance, I felt tremendous, like my old self. Could this have been the result of the kind of adaptation you were talking about? Three days after the trip ended I started with the Auto machine, and the first data reports. I felt OK for a few days, but it has been downhill ever since. Now my energies are sagging, and it takes discipline to keep exercising, but I am loathe to give it up. Could this experience indicate a responsiveness to the kind of therapy you were mentioning?
If we are talking about adaptation, I am mindful that for the first week on the Auto I was using 8-12 auto, and was typically about 40+%PB, and my AHI was about 30. Then I had three days where my AHI went down to about 20, one day in the midst of that as low as 15. After that, because of our discussion, I went back to straight cpap. Could that have been initial adaptation, that might have continued?
From all I've read, ASV would still be the favored approach.
Your comments would be much appreciated. I'm going to pursue my sleep doc as well. Thanks again.

Stevealive, regarding your specific questions about CompSAS physiologic adaptation: contemporary sleep science doesn't YET have those particular answers for you IMHO. My understanding is that very little epidemiology or longitudinal studies have been performed to date regarding physiologic pressure-adaptation in CompSAS patients...

BTW, I see you live in Durango, Colorado, where the elevation is significant. Was your PSG performed at considerably lower elevation? If so, your SDB severity might have been initially under assessed/diagnosed in a lower-altitude sleep lab: http://chestjournal.chestpubs.org/conte ... /1744.full.

David Patz, MD, FCCP, et al wrote:Central apneas may be a manifestation of instability in ventilatory control.4 Wellman et al5 found that the OSA patients with the most instability in their ventilatory feedback loop, measured with the proportional assist ventilation technique, had the greatest decrease in their AHI in response to oxygen.

That seems to imply your extended adventure in any lower-altitude desert canyons just might have afforded you less-severe sleep disordered breathing as well.

-SWS, my sleep study was done here in Durango. I hadn't thought about the lower elevation of the desert trip, because my period of feeling better began here in Durango, and lasted through a week of daily exercise preparing for the trip, and a few days after my return. The elevation change was about 3,000 feet, so that might have been a factor for the time I was there.
I have not been able to get a response from my sleep doctor yet. Until I do, I don't know what my options are, other than to continue with the cpap setting, maybe raised from 8.5 to 9 to favor the OA's. There's only one sleep center here in town, and so far my doctor and the nurse practitioner I've seen there are the only names I've heard associated with it. While I'd prefer to give things locally a chance to work out, if need be I'll go out of town to get a better doctor to work with. I've been told there is a sleep center in Denver that is highly regarded. Albuquerque is half the distance and an easier drive. Any notion of what might be available there?

Unfortunately I don't have first-hand knowledge of sleep centers in your neck of the woods, Stevealive. However, this AASM referral page just might help in your search---should you actually require a new-doctor search:
http://www.sleepcenters.org/

I managed to get a reply from my sleep center today. Bless their hearts for their efforts, but I think they are up against their limits. I had to hand carry in my report for the second time, because the doctor had locked it in his office yesterday, and he was not scheduled to return until the 23rd. Turns out they have two doctors (one left recently for health reasons), each scheduled for 5 days a month in the sleep center after their main duties in the ICU, and a nurse practitioner 2 days a week. When the secretary saw my reports from the PR1 Auto she said they never look at anything like this. I received a call from the nurse, who also said she had never read anything like it either, and she had gotten help from their RT to read it. The sleep center is a new innovation in a state-of-the-art hospital that is only a few years old. These people have been good to me so far. I don't think the sleep center operates on the level that one in a major city would. I may be looking for something in Albuquerque after all.
The nurse's recommendation was to go back to the 9cm cpap that I was on in the past, and follow up with overnight oximetry after a few days. We talked about the rising CA's as the pressure rose enough to deal with the OA's, but she didn't think that qualified me for CompSAS. Her next recourse would be supplemental oxygen, which I expressed a desire to avoid. When I asked about ASV, she didn't think it would be the thing for me, but it could be a possibility after we tried other options. Perhaps I'll still get a call from the doctor regarding the copy of my report that he has, and if not, I can approach him after I have a few more days of data to show on the 9cm cpap.
So I don't have a direct route into an ASV titration. For now I think I have to go along with what is here locally, and be hopeful that I can achieve the energy level that I did before on the 9cm cpap. In the meantime I'll check what Albuquerque has, and try to initiate contact with them. I'll also look a bit more into the Encore Pro software, if that might help with the discussion here, and the mask leaks. Any other suggestions?

stevealive wrote:... Any other suggestions? ...

Well, I can not offer a lot more than what SWS has been able to offer. However, since you are starting to look into working with another doctor / sleep center, you might want to be certain you locate a doctor, who is board certified is sleep medicine. For example, the American Board of Sleep Medicine:

http://www.absm.org/

Or as an example from my doctor, he is a "Diplomate, American Board of Psychiatry and Neurology with Subspecialty Certification in Sleep Medicine and Vascular Neurology".

You need someone who knows more than just a middling amount about sleep medicine.