Sleep Doctor Visit: Aerophagia and Changing Our Pressures...

[LoQ]

These days few doctors theoretically equate CPAP-induced central apneas with the Herring Breur Reflex, however. Most doctors now equate CPAP-induced central apneas with CompSA and resulting CO2 imbalance.

Can you explain what that means? That CO2 imbalance is caused by CompSA, or caused by CPAP therapy? What what is the imbalance? Too high? Too low? I have not heard this before and am curious about it.

[-SWS]

These days few doctors theoretically equate CPAP-induced central apneas with the Herring Breur Reflex, however. Most doctors now equate CPAP-induced central apneas with CompSA and resulting CO2 imbalance.

Can you explain what that means? That CO2 imbalance is caused by CompSA, or caused by CPAP therapy? What what is the imbalance? Too high? Too low? I have not heard this before and am curious about it.

Hello, LoQ... CompSA is a hypocapnic disorder once CPAP is applied. So CO2 levels drop too low relative to an apneic threshold.

CPAP treatment unmasks/increases that CO2-based sensitivity---resulting in treatment-emergent central apneas. Here are some interesting articles:
http://www.rtmagazine.com/issues/articl ... -11_03.asp
http://www.chestnet.org/accp/pccsu/comp ... a?page=0,3
http://www.sleepreviewmag.com/issues/ar ... -06_03.asp

Fortunately many CompSA patients gradually adapt to ordinary CPAP after a couple/few months. However, others require the kinds of specialized treatments mentioned in those articles.

[M.D.Hosehead]

CPAP treatment unmasks/increases that CO2-based sensitivity---resulting in treatment-emergent central apneas. Here are some interesting articles:

-SWS,

Thanks for these links.

Like many here, I have some CA's (about 1.9 to 2.3 per hour), caused/unmasked by xPAP. The PSG reports from my diagnostic and titration studies don't say how many of the apneas I had were obstructive or central. My titration study does say that centrals were observed during the titration.

From my understanding of the articles you linked, as well as Wikipedia, it seems that, even if there are CA's, if AHI remains below 5 and there are no desats, there would be no cause to intervene. Is that correct?

[jnk]

The PSG reports from my diagnostic and titration studies don't say how many of the apneas I had were obstructive or central. My titration study does say that centrals were observed during the titration.

Any chance you can get the full PSG reports, not just the summaries?

[klgm326]

CPAP treatment unmasks/increases that CO2-based sensitivity---resulting in treatment-emergent central apneas. Here are some interesting articles:

-SWS,

Thanks for these links.

Like many here, I have some CA's (about 1.9 to 2.3 per hour), caused/unmasked by xPAP. The PSG reports from my diagnostic and titration studies don't say how many of the apneas I had were obstructive or central. My titration study does say that centrals were observed during the titration.

From my understanding of the articles you linked, as well as Wikipedia, it seems that, even if there are CA's, if AHI remains below 5 and there are no desats, there would be no cause to intervene. Is that correct?

According to my doc, that is correct!

But now I'm bummed! I did as he requested and changed back to 11. Last night my AHI was 5.8!! I know that's not terrible, but is it possible that my body had "gotten used to" 11.6 "ish" that I had it on for about a week? (I guess I'll find out, right?) ...and it will come back under 5?

On the positive, I did up the EPR to 3 as he suggested, used the Saline spray and voila...no aerophagia!! So, 1/2 my problem was resolved...


I guess we can't have everything all at one time!

[SleepingUgly]

I have never seen any research that indicates there is a clinically meaningful difference between an AHI of 2 and one of 5, or 1 and 4. I bet it's not out there.

And I still can't find the article that would indicate that an artificial cut-off of 5 was empirically-derived, although I've been variously told that it was and that it was not. I bet there is no data-driven reason to be upset about an AHI of 5.8 and happy about a 4.2.

[klgm326]

Well, that's essentially what the doc said -- if on average I'm under 5, we're good. I was just hovering around 1-2 with higher pressure and then, bam, up to almost 6 (just looks so icky on the graph with all the little signs popping up...lol). He equated this with a diabetic taking his blood sugar every hour and stressing every time it went up or down. Yes, I do tend to overthink EVERYTHING!!!
Thanks for your reply! (I suppose I should rejoice in NO GAS!! )

[-SWS]

Like many here, I have some CA's (about 1.9 to 2.3 per hour), caused/unmasked by xPAP. The PSG reports from my diagnostic and titration studies don't say how many of the apneas I had were obstructive or central. My titration study does say that centrals were observed during the titration.

My understanding is that some centrals during the titration are not at all uncommon. And a low residual central AI around 1.9 or 2.3 is not uncommon. At that subclinical rate the etiology might have more to do with sensory-based stimulus/response (thus post-arousal CA's) than an inherently sensitive CO2-based apneic threshold. CPAP introduces significant sensory input during sleep IMO.

From my understanding of the articles you linked, as well as Wikipedia, it seems that, even if there are CA's, if AHI remains below 5 and there are no desats, there would be no cause to intervene. Is that correct?

And that's my understanding as well.

Thanks for these links.

Here's a much broader discussion of apnea pathogenesis that you might like as well:
http://ajrccm.atsjournals.org/cgi/conte ... 72/11/1363

I have never seen any research that indicates there is a clinically meaningful difference between an AHI of 2 and one of 5, or 1 and 4. I bet it's not out there.

I agree that the AHI=5 cutoff is probably arbitrary versus clinically meaningful. We have several patients on this board who claim to feel noticeably poorer when their residual AHI climbs above 3 (versus 5). Then there are some untreated patients with moderate or worse AHI scores who are essentially asymptomatic.

[elena88]

I agree that the AHI=5 cutoff is probably arbitrary versus clinically meaningful. We have several patients on this board who claim to feel noticeably poorer when their residual AHI climbs above 3 (versus 5). Then there are some untreated patients with moderate or worse AHI scores who are essentially asymptomatic.

I have often read here that people can feel the difference if they have a bad night, and strive to get under two ahi or one.. It would be
interesting to have a blind wine type tasting study.. where everyone got up, guessed their ahi by how they felt, wrote it down, THEN checked
the machine.. that would be facinating.. and I know I would be wrong every time!

A contest might be fun? who can get the closest guess to their ahi every day for a week..

For me, I cant tell the difference between a 6.0 night and a 0.1 night. I guess Im not very sensitive that way.. or just really used to apnea events!

[SleepingUgly]

Elena, you are funny! But seriously, I think that once people have established a consistently good AHI and are well treated and stable, daily AHI monitoring should be done only by those who are not phased by normal variance... Those that get anxious by clinically insignificant changes would probably do better to look at it less frequently and then rely on averages. (I think the same is true of the stock market!)

[klgm326]

Ok....maybe 5.8 wasn't statistically significant, but this morning it was AHI 11!!! AI 10.4, Obs: 7.4, Central 3, Hyp .3 ! Could all of this be from having my EPR set up to 3?? This is almost as high as my initial sleep study!!

Should I call the doc? By having set my pressure higher for the past week, did my body get used to that higher pressure?? Any ideas??

Thanks guys...now I am beginning to stress a little...oh, and my leak rate was great! (1.2 at 95th% on my new Liberty mask!)

[cflame1]

keep in mind that EPR 3 will lower your pressure 3 (at least that's what I've been told for how Resmed works).

There is a potential that EPR 3 may be lowering your pressure to the point that it isn't covering what you need.

[klgm326]

Really?? I think I may have to re-think that one!! (we did that for the aerophagia, but gas vs. apnea??...hmmm) I don't like these numbers!!
Thanks!

[ozij]

Hi all,
With regard to changing our own pressures...
1) He told me he preferred that I stay at 11, even though my "evidence showed" that my AHI went down with a 11.6 - 11. 8. He explained that there's a fine line here in that with too much pressure, the lung capacity grows, and this somehow tells the brain to breathe less, thereby causing more Central Apneas (now that's my paraphrasing of what he said). In other words, anything under 5 is good and stop sweating the small stuff... The goal is not perfection or 0, it's to be "normal" which is under 5. And there is often a fine balance. (So I will respect his wishes on this one, unless my data starts showing a problem...)

Something doesn't make sense here.
You machine records apneas. It records both central apneas and obstructive apneas. If your results at higher pressure are better, then you doctor's concerns about pressure induced apneas are unwarranted. You would see the central apnea in your data, as apneas, or as central apneas.

So: either you may have misunderstood your doc (did he use the term central apnea?) or your doc is a great scientist of the human body, but does not know enough about the basics of how Resmed machines identify, record and report breathing data. Your data is evidence that -whatever else may be going on - at 11.6 - 11.8 you do not have pressure induced apneas. Perhaps he has valid reasons to not want you at that pressure -- but pressure induced apnea cannot be a valid reason based on your data.
How do you feel?

[klgm326]

Something doesn't make sense here.
You machine records apneas. It records both central apneas and obstructive apneas. If your results at higher pressure are better, then you doctor's concerns about pressure induced apneas are unwarranted. You would see the central apnea in your data, as apneas, or as central apneas.

So: either you may have misunderstood your doc (did he use the term central apnea?) or your doc is a great scientist of the human body, but does not know enough about the basics of how Resmed machines identify, record and report breathing data. Your data is evidence that -whatever else may be going on - at 11.6 - 11.8 you do not have pressure induced apneas. Perhaps he has valid reasons to not want you at that pressure -- but pressure induced apnea cannot be a valid reason based on your data.
How do you feel?[/quote]

You know...after I considered what he said, you're right...The central apneas were listed there and yes, he did say "central apneas". I certainly could have misunderstood something, but the gist was definitely pressure-induced central apneas.

Honestly, I don't know how I feel. It's been a little under a full month. I'm on my 3rd mask and think I've finally found the right one. I was feeling some better (but was also on a prednisone taper for a bad reaction to chigger bites..yes, another story...but I always feel better on prednisone) and that has finished, so I feel tired again. But I was definitely disappointed when I saw the numbers this a.m. I haven't had these numbers since I started treatment...even when I was having terrible leaks! I just wonder if my body "liked" the higher pressure and isn't taking to lowering it??