That's my question in the subject line.  

Upon finally viewing my results, it appears that at the high pressure they gave me - 15, that I start having more 'events'.  What does this mean?

hi linnea,

i'm no expert, but i think i've read somewhere that too high a pressure can trigger "central" apneas, i'm not sure though!

Hi Linnea,

Papster was right, pressures which are too high can trigger central apneas.  However, you need to go back and ask your doctor specifically what "events" in your case refers to.  Central apneas are not caused by a physical blockage, but by your brain not sending the impulse to breath.

Vicki


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Being defeated is often a temporary condition. Giving up is what makes it permanent.
Marilyn Von Savant

That which does not kill you makes you stronger-Friedrich Nietzsche
Friedrich must of had apnea.

And like magic the results appear!



The respiratory event type is not identified in the graph.  Of course, what is odd is that the events were well controlled at the lower pressures, and since the entire time was spent supine and there is REM, there doesn't appear to be any good reason to increase the pressure after the first REM period.  Knowing the event type will be helpful, of course, if they are all central then it could be an overtitration, if they are something else, actually I would look for artifact/CPAP intolerance.

There's some significant desaturation associated with it.  However, the desaturations appear poorly defined, almost as if it were artifact.  You've got desats with no events.  But if it isn't, you have to able to explain them somehow.

There's a few PLMs, not a particularly great deal of them tho.  And in stage 4?  Not usually.  While awake?  Not possible.  Isolated PLMs?  Can't be, you need at least a group of 4 within a couple minutes to be counted.

Note that there are no arousals associated with the events.  Odd.  As a matter of fact, there's no arousals at all, during the whole night.  Real odd.

The pattern of Stage 4 sleep is out of place, there's way too much.

The CPAP pressure seen at about 150 minutes should have been fine, looks to be about 8 cmH2O.  Unfortunately, as Linnea had mentioned before, there was (a, some) desaturation down to 48% in the diagnostic study, which of course would be quite worrisome.

Yet, a review of that study:



Shows the entire oxygen saturation graph gone.  And a ton of Stage 4 again.  Almost unheard of.  And all the arousals and respiratory events are exactly the same duration.  Hmm, maybe somebody's just running the computer analysis and not double-checking the validity.

If the oxygen desaturation indeed went down to 48%, I don't think you can confidently change pressures safely without monitoring.  Yet, the reliability of everything in these studies comes into great question.  Linnea has great patience and understanding.  Me, right about now my head would explode.

This whole situation needs a re-do.
sleepydave

How does over titration trigger central events? As I understand it, they result when the brain fails to signal the breathing muscles to breathe, or when the signal from the brain to the muscles is impeded. But how does over titration cause interference with the signal?

There are several components that go into generating central apneas, and this is a great segue for

The Mother of All Threads

sleepydave

Just  a note to say that I was not sleeping on my back during the 2nd study.  I cannot fall asleep on my back and I know that I woke up and changed masks and positons in the middle of the night.  I fell asleep and woke up both times on my side. That straight line is very curious for positon.

OK, here's a follow-up overnight oximetry that was done, and thanks for sharing this Linnea, cause this is a great example of total disaster, but obviously, if you don't know what you're looking for, you can't find it:



See that line that says "% Artifact"?  That means invalid signal, or no signal, whatever, it's junk.  89.4%!!  And almost all of the valid signal is at the beginning, so that was probably wake anyway!  So this is a report of nothing!!

The Sword of the Angel of Truth will continue to cut through all these lies!!

(What?  OK, I'll tell 'em.)

Ahem, since it's Christmas, the Angel of Truth is helping with the presents, shoveling after the reindeer, etc.  We're on our own.

No problem, we'll get it done.

Sounds like the herd upstairs is about to come stampeding down.

Merry Christmas.
sleepydave

Oh my.  So does this mean that the few blips on there are the 11% of non-artifact?  They don't look too good.  And the rest is a mystery.
This is turning out to be yet another - trust your gut - validation moments.  I was suspicious of them from day one and it just keeps getting worse.

sleepydave wrote:

There are several components that go into generating central apneas, and this is a great segue for

The Mother of All Threads

sleepydave

You're right, Dave. That *is* the mother of all threads.     Some pretty wacky stuff mixed in with some very interesting and informative posts.

Still don't know if I fit the CSDB profile exactly, but I plan to ask my sleep doc about it in January. The last couple of weeks I've been having trouble breathing while awake. No wheezing or anything, just SOB. Could be from anything but can't wait for that next appointment.

Right, Snooze, your titration was kinda looking that way.
I think from that thread you can see there's a lot more to centrals that meets the eye.  I know, everybody says, "Look, centrals, you've overtitrated".  In the case of an uncomplicated CPAP titration, tho, they're probably more from intolerance rather than something physiological.
In plain old OSA, you could probably run the CPAP off the chart and you wouldn't generate a central apnea.
If, as a consequence of overtitration, the patient was having arousals, and having brief periods of hyperventilation following the arousal, and that resulted in a cental apnea, then the cause is indirect.  These centrals are quite sporadic, you'll just see a few at "overtitration", not like an AHI of 30, more like 3.0, if that.
Even if you overtitrate with BiPAP, you probably won't see centrals.  The breathing rate simply slows down, your pCO2 stays the same, and centrals are not generated.
Now, if you have chemical control instability, and/or cardiac flow problems, then ventilatory problems can be generated by any kind of pressure, and they will come in bunches.  Like AHI 40-60 as they become cyclical.
The source of the centrals can be determined on the PSG, if they are post-arousal or truly centrals.
sleepydave

Linnea wrote:

That's my question in the subject line.  

Upon finally viewing my results, it appears that at the high pressure they gave me - 15, that I start having more 'events'.  What does this mean?

Is there also an increase in stomach bloating?  I found that when they lowered my pressure, I had less bloating.


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No, no real stomach bloating.