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Clear Airway Clusters
#21
Hi Mondo, thanks for that informative post. I wondering how it diagnosed a CA event. I'm going to try turning down my IPAP to 16 tonight and see what happens. I'm thinking about turning down the PS to 4 too. I get a little aerophagia sometimes and I just read that a high PS can contribute to that.

(03-25-2015, 07:14 PM)trish6hundred Wrote: Hi CPApnea,
WELCOME! to the forum.!

Good luck to you at your next apointment with the new sleep doc.
Much success to you as you continue and fine tune your CPAP therapy.
Thanks!

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#22
(03-26-2015, 01:17 PM)CPApnea Wrote: Hi Mongo, thanks for that informative post. I wondering how it diagnosed a CA event. I'm going to try turning down my IPAP to 16 tonight and see what happens. I'm thinking about turning down the PS to 4 too. I get a little aerophagia sometimes and I just read that a high PS can contribute to that.

(03-25-2015, 07:14 PM)trish6hundred Wrote: Hi CPApnea,
WELCOME! to the forum.!

Good luck to you at your next appointment with the new sleep doc.
Much success to you as you continue and fine tune your CPAP therapy.
Thanks!

I suggest one thing at a time.
Try IPAP max to 16 first and wait a few days. Then try lowing the allowed variable PS (Pressure Support.) Reduce PS range 1 cm-H2O at a time waiting a couple of days between. A likely range may be in the 4 to 5 range.

If OA and CA cannot be brought to a reasonable balance, then a more complex machine known as an ASV may be required. But, I think you can tune to a reasonable level with the machine you have.

Remember, I am not in the healthcare field, I'm a retired US Airman and an engineer.
INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
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#23
Noted. I'll still take the doctor's advice when I see him next week. I like tinkering and trial and error though, and this will give me more data to bring.
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#24
(03-26-2015, 02:54 PM)justMongo Wrote: Remember, I am not in the healthcare field, I'm a retired US Airman and an engineer.


.....but he thinks cars don't have carburetors in them. Humphhh. How could they possibly buret if they didn't?

I'm looking forward to hearing how you come out after lowering the pressure a bit.

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#25
(03-26-2015, 09:36 AM)Terry Wrote: ...

My expectation is based on physics and math.

Terry

Well, that certainly clears that up.

I base my opinion on physics also. But mine is only an opinion, not an expectation of surety. And math? There is no math that can explain this, and to think so would indicate a pretty fuzzy idea of what math even is, unless you would care to enlighten us.

Oh, and this is also supported by tons of anecdotal evidence on this forum and others, and various other sources.

I also don't think a machine that flags an event when I simply hold my breath while awake while changing sleeping positions (something most of us do unconsciously) or if I purposely breathe shallowly and calls that a sleep apnea event can be very good at all in being accurate about what it is reporting.

My PSG split sleep study with xPAP showed no CAs. My home sleep study with no xPAP also showed no CAs. Yet every night with xPAP my CAs are twice what my other events are, or at least as reported. And they flag at low pressure levels. Explain that with physics and math, both of which I hold degrees in.

I'll explain part of it for you.

The xPAP alone doesn't have a good ability to distinguish an actual CA, especially when you are awake, so many are false positives, and here is exactly why: the algorithm for CAs is to sense a halt in respiration, FOT the airway to determine if it is open, then wait and see if respiration returns within a prescribed time. If not, a flag is thrown. It really doesn't get much more sophisticated than that, because there is no magic bullet that will tell the xPAP more about what is going on from simply relying on sensing respirational feedback in the pressure system.

That is not an indication of a CA event, that is an indication that respiration paused for longer than normal without the airway being restricted, which is not the definition of a central nervous system-caused apnea event, only an indication that there was halted respiration.

That is all it can detect. It can't detect an actual CA, because there is no way to do that. It can only detect conditions that indicate that there MAY have been clues that MAY be describing a CA event, with no proof positive either way. So it is more akin to a wild-assed guess based on limited information. Which leaves the door wide open for false positives, meaning the xPAP does NOT have a "pretty good idea" whether there was an actual CA event or not. It's plenty smart, just not smart enough to do that.

xPAP in a PSG study probably also throws false positives, but those are thrown out because the other, better PSG data collected at the same time recognizes them as false positives, something the xPAP can't seem to do on its own.

And that probably explains completely why a patient presenting with no CA events without therapy, also presenting with no CA events in the PSG study with xPAP, might present with reported CA events when the therapy is in place and is only reported by the xPAP itself. Some of those are very likely false positives, and that is supported by reports from experts in numerous articles, not to mention in person directly to me by a practicing neurologist with a fellowship in sleep medicine. I've already googled and read the articles, so if you want to google them and read them too, be my guest. Be sure to include all of the experts that say this is not what is happening, too, because that will not take very long at all, since it appears that none have.

Don't get me wrong, I am totally on board with xPAP, I think it is a godsend. It is rare for any medical condition to have a therapy with virtually 100% effectiveness, virtually no side-effects, and is very minimally invasive. Its a miracle. It changed my life.

And the technology is amazing and well-advanced. But that does not mean it is perfect, or that there is a good way for an xPAP to accurately flag CA events. Everything has limitations. The $10,000 Apple Watch will still need to be charged every night. Not every problem has a perfect solution.
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#26
(03-27-2015, 01:19 AM)TyroneShoes Wrote:
(03-26-2015, 09:36 AM)Terry Wrote: ...

My expectation is based on physics and math.

Terry

Well, that certainly clears that up.

I base my opinion on physics also. But mine is only an opinion, not an expectation of surety. And math? There is no math that can explain this, and to think so would indicate a pretty fuzzy idea of what math even is, unless you would care to enlighten us.

It's possible to tell whether your airway is open by sending down a pressure pulse and measuring the returned waveform shape and timing.

The waveform and timing is different depending on whether your airway is open or not.


(03-27-2015, 01:19 AM)TyroneShoes Wrote: I also don't think a machine that flags an event when I simply hold my breath while awake while changing sleeping positions (something most of us do unconsciously)

It's irrelevant if you decide to stop breathing while awake; that's your decision. If you stop breathing while asleep for more than 10 seconds, with an open airway, it's a CA.

(03-27-2015, 01:19 AM)TyroneShoes Wrote: I purposely breathe shallowly and calls that a sleep apnea event can be very good at all in being accurate about what it is reporting.

The machine can't measure human deception or intent. If you conciously decide to breathe shallowly, that's your issue and not a shortcoming of the machine, which treats Sleep Apnea, not people intentionally screwing with it.

Terry

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#27
I think that we are having some word usage problems here. Most of us are aware that the machine can only flag clear airway apneas. In common usage people (myself included) tend to call them centrals although that is not technically correct. So technically your calling the CA flagged events central apneas is incorrect.

There is another way of looking at this. If you go to bed in the evening with no snow on the ground and then get up in the morning with snow all over, it is a reasonable assumption that it snowed during the night. Of course, someone could have trucked in snow and dumped it all over everyone's yard and roof but that is not as probable.

Your claiming to have read numerous articles supporting your opinion but not naming even one of them is not convincing at all. It just makes it sound like there are no such articles

Apnea is defined as a cessation of breathing. So if you intentionally stop breathing while awake with the machine operating and it scores it as a clear airway apnea, the machine is correct.

Best Regards,

PaytonA
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#28

(03-27-2015, 11:29 AM)PaytonA Wrote: ......... If you go to bed in the evening with no snow on the ground and then get up in the morning with snow all over, it is a reasonable assumption that it snowed during the night. Of course, someone could have trucked in snow and dumped it all over everyone's yard and roof but that is not as probable.

..and yet, the trucking thing would be the only possible explanation for us here in the Pacific NW Coast Sun Belt.

Poor CPapnea. All he really wanted was to understand his reports and to have a nice nights sleep.

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#29
Hey don't mind me, I'm glad my thread is generating discussion. The CA events were kind of mystical in previous threads I read and I suspect they will continue to be after, but I'm getting a better idea of why that is now.

As for me, last night I turned the max IPAP down to 16 and my AHI was 2.50: CA Index 2.02, Hypopnea Index .48. Those and the other events were all in line with previous results I've seen, so it did not seem to be any less effective. Still room for improvement of course, but I'll stick with these settings for a few nights.
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