CPAPtalk.com

carbonman wrote: I think that SWS' real job is spinning for the current presidential administration....
doesn't matter who is actually in office. Words mean what he says they mean.

He just posts here to unwind and a few laughs.

You're so funny, CM!! But I still want so much to understand what SWS means. Seriously!! And I'm not sure I follow the last paragraph.....

plr66 wrote:

-SWS wrote:I agree that only half-a-cm change seems extremely counterintuitive regarding substantial AHI spikes. However, sometimes dyscontrol in individual physiology (no longer talking about population-based epidemiology) is a matter of discrete or sudden thresholds of dyscontrol---rather than smooth gradations of increasing dyscontrol.

I'm behind Dori here, SWS, and would so appreciate your saying this in another language. Sorry. I followed you well until this paragraph.

SWS, I appreciated the link to the Hering-Breuer reflex as it offers a very feasible possibility why the brain might not send a signal to breathe under too much pressure (i.e. to protect the lungs from over-inflating, if I understood this correctly). I always like explanations that make some organic sense as opposed to "the brain just decides not to breathe". In my case I never tried a pressure over 10 cm, but if it seemed physically uncomfortable to me I can definitely believe protective mechanisms in my body might be triggered to try to protect my lungs.

I think I understood that last paragraph. Although most people might respond to certain treatments or situations in expected ways, individual mileage may vary. So, a particular person could have a threshold of CPAP pressure where breathing would go significantly out of control (a large increase in apneas after a small change). We laymen might intuitively expect something else, a smooth rise in the number of apneas at each increase in pressure once we've passed our personal ideal treatment range.

Although I do have to say this is the first time I've seen the word dyscontrol associated with an autonomic (non-voluntary) function like breathing.

Now I understand and can relate to that. My husband's titrated pressure was 13cms but when I tried it a few times he had very restless,leaky nights with higher AHIs and said he didn't "feel right". But he does fine with 1cm less at 12cms. Have I got it right? Scarlett, it sounds like you attend SWS University1

Dori, what you are describing matches my experience, so on that basis you "got it right". But remember, SWS hasn't confirmed my diploma.

My husband and I had a rousing discussion over dinner. If the good/bad threshold is so close I can see why the medical folks are leery of people randomly adjusting their settings. (Wait, wait, don't yell at me...) At the same time, I was pretty evidently undertitrated slightly, and your husband was apparently overtitrated. I'm firmly convinced that my well-meaning sleep lab is limited in the precision of their titration by just how well I slept under those conditions. And I don't begrudge them that 0.5 cm difference--except that I'd probably still be non-functional if I hadn't addressed a setting change myself. There was another thread about studies using auto-adjusting equipment at home to diagnose. I'm very hopeful about those, because I really think diagnosis in the home is the way to go.

I more and more like the explanations of OSA vs. CSA in this thread and really thank SWS for it. A lot to think about.

Scarlet834 wrote: I always like explanations that make some organic sense as opposed to "the brain just decides not to breathe"....

Although I do have to say this is the first time I've seen the word dyscontrol associated with an autonomic (non-voluntary) function like breathing.

Loop Gain Control Theory is one model commonly applied to autonomic respiration. And in any control theory there can also be dyscontrol. Blood-gas chemoreceptors are yet another control mechanism that can yield central apneas when in a state of dyscontrol.

Now these latest I'm going to have to go back to after a nice night of CPAP. Thanks for linking.

For my own curiosity, you were already very knowledgeable about all this in 2005 when you joined the forum (I'm looking at some of your older posts, just got through looking at Command on Apnea). Did you get into all of this by way of learning about your own treatment? Or, is this a related field for you in the first place? Seriously, you seem to have a pretty awesome body of clinical knowledge at your fingertips.

Scarlet834 wrote: Did you get into all of this by way of learning about your own treatment?

That's it exactly, Scarlet834. But I've been at it since 2003 or perhaps even 2002.

Scarlet834 wrote: Seriously, you seem to have a pretty awesome body of clinical knowledge at your fingertips.

Mr Google has the awesome body of clinical knowledge at our fingertips!

-SWS wrote: I would suggest experimentally mouth-taping while using your full-face mask. If the problem goes away, then you can assume that mouth-breathing even with a full-face mask is your culprit. Otherwise, I would suspect the greater volume dynamics of a full-face mask somehow might not sit well with your physiology.

I'm aware that one night does not an experiment make. Just for the first night with the shallow mask and mouth taped, there was a mild decrease in my AHI of about 1.0, which is much less than I sometimes fluctuate from night to night these days anyway. So I'm not yet able to jump to the conclusion that my mouth breathing in the mask has been responsible for the big increases in my AHI.

SWS, I appreciate your input with this puzzle. Perhaps the FFM does tend to move my lower jaw inward, which would likely tend to close off my airway a bit? I have had a lot of TMJ work done (with questionable long-term results), and currently wear a small, incredibly expensive appliance to keep from grinding my teeth--so will need to think about the idea of using an OTC mouth guard. But the idea of pulling that lower jaw outward makes sense, especially if the FFM is pushing it in.

In terms of volume dynamics, I guess I always assumed that the mask engineers would have worked out all that dead-space math to pretty much equalize the effectiveness from one mask shape/volume to another.

plr66 wrote: Perhaps the FFM does tend to move my lower jaw inward, which would likely tend to close off my airway a bit? I have had a lot of TMJ work done (with questionable long-term results), and currently wear a small, incredibly expensive appliance to keep from grinding my teeth--so will need to think about the idea of using an OTC mouth guard. But the idea of pulling that lower jaw outward makes sense, especially if the FFM is pushing it in.

That's a pretty darn good theory in my book. So if you decide to experiment with different chin strap designs, be careful of the designs even slightly more prone to pull the mandible back.

And speaking of puzzles, what has Muffy presented us with directly above? It looks like 6 nights of Puritan Bennett data at 10.5 cm and 5 nights of Puritan Bennett data at 10cm. Only half-a-cm difference between those two tables... But the "AH Index" and "utilization hours" are cryptically missing from that 10.5cm table.

Hmmmm.....

P.S. Not to miss the phpBB commentary!

Muffy wrote:

Okay, Muffy, there's no question that my memory function is impaired...but can you give a hint as to when/where these numbers were posted and how they relate to the discussion? I keep my sleep hygiene pretty well up to snuff, generally sleeping 7.5-8 hrs every night on weeknights, and maybe 8.5 hrs on weekends....have never in my memory posted sleep times, much less any which would look like what you have posted here. So....Huh???

Well, those are from viewtopic/p417709/viewtopic.php?f=1&t=4 ... 65#p403465 to try to make some sense of the data available so far.

Muffy

Muffy wrote:Well, those are from viewtopic/p417709/viewtopic.php?f=1&t=4 ... 65#p403465 to try to make some sense of the data available so far.

Muffy

Where did the utilization hours come from, Muffy? Not sure they are mine at all! (By the way, I don't know what phpBB stands for, but I sure like the table you made).

Ah... okay. Thanks, Muffy!

Plr66- you gave total apnea count and AH index for your 10cm data only. Utilization hours can be calculated from those two two data fields. Since you didn't present AH index for your 10.5cm nights, utilization hours are also unknown...

-SWS wrote:Ah... okay. Thanks, Muffy!

Plr66- you gave total apnea count and AH index for your 10cm data only. Utilization hours can be calculated from those two two data fields. Since you didn't present AH index for your 10.5cm nights, utilization hours are also unknown...

I'm baffled because unless I don't remember having been sick, I can't remember a time in my life when I could stay in bed that long! I also have never had a night without keeping my mask on for then entire 8 hour night. Ever. Nor have I had a night with only 3.5 hours...I just don't get it. Not to derail the issue here!

EDIT: Just scanned my software record since June, and not a single night varying from 7.5 up to a max of actually 9 hrs. I'm not sure which nights I tracked for the data in the September post, but fear that I may have thus copied it wrong. UGH! Perhaps more current data would help? Or not?