No Answers Yet For Problems With ASV

[Mr Bill]

Hmmm, those timed breaths (TB). I wonder what internal backup number is controlling that in the ASV. I could easily imagine that the regular intervention of those timed breaths might disturb your sleep on some unconscious level. The width of the bar seems to be larger for smaller breaths. Looking at 12:18am it looks like the TB blocks tried to intervene when your breathing slowed down for just a bit. It appears we can only see that slowing down when the intervention is ignored. But there are whole long blocks where TB is initiating breaths and you are taking them. If the block thickness corresponds to the degree of intervention, it seems like the TB block wax in thickness and then wane. But the waxing and waning of the timing seems to be independent of the height of the pressure pulse.

Between 3:30-4:00am you have quite a bit of variability in timing of breaths but very few TB interventions. That makes me think that when TB and PP are intervening at the same time, its for variability outside of that "normal" range. If I were a programmer coding this I would examine the previous pulse train and determine an interval that I would be looking for before I decided a breath was about to be missed. Knowing that interval, I would then put in a threshold value to allow for some variation in the interval. I actually did something like this when I wrote some code to examine d-spacings to identify minerals from a X-ray diffraction database knowing that the database came from a wide variety of machines and conditions and that the actual X-ray diffraction pattern taken in our lab was for a specific mineral plus some slop due to impurities, lattice imperfections, and variability in sample preparation.

So I get the intuition that the threshold for allowing some variation in the train of breaths in the ASV is the possibly functionally named Inspiration Time. Maybe your respiratory therapist can determine if that needs to be adjusted so that interventions are appropriate. But maybe its perfect just as it is. The pressure EPAP does not seem to climb much so it would appear that it does not take much to fix you right up. Its just that the patient initiated graph looks awful. But as I have noted before, it may not be awful if you are doing most of the breathing work.

From 4:24-4:54am its both TB and pressure pulses like clockwork. I have no idea how much of the breathing work you are doing there because I do not know how much pressure differential it takes to inflate our lungs. They look like pretty dramatic pulses telling you to breath. But the overall pressure does not seem to be large. Maybe NotMuffy can enlighten us as to whether those pulses are more like triggers for breathing or more like giving you a breath.

As to cause, maybe its a stage of sleep or maybe you have turned on you side.

My own central apnea is very well controlled by my ASV with my settings if I am sleeping on my back. Since my CSA started, I can't fall asleep at all except on my back. If I want to roll over to either side I have to be already asleep and still sleepy to keep sleeping because my hyponeas go up dramatically and my patient initiated breaths drop and my breath pauses and the ASV's interventions start waking me up. I'm unfortunately a light sleeper and I make a note of the time just before I roll over to the side on the rare occasions that I try it. So, I know those sleep disturbances are from trying to sleep on my side. Let m just say; It rather freaks me out that I can no longer sleep on my side.

I wonder if I can talk my DME into getting me a System 1. I love this extra data.

[NotMuffy]

That makes me think that when TB and PP are intervening at the same time, its for variability outside of that "normal" range.

I do not believe that is possible in this configuration, and that the EPAP Algorithm resorts to the classic Popt - Pcrit - Pther approach for obstructive event identifiaction and treatment.

From 4:24-4:54am its both TB and pressure pulses like clockwork.

I think one needs to pay careful to the nomenclature. There are no "Pressure Pulses" per se.

[NotMuffy]

there is also the preaforementioned issue of the breathing irregularity of phasic REM. And I think that as the REM-suppressant medication effect wears off in the latter part of the night, you have a pile of it (that might be an interesting thing to look for in your raw NPSG data).

When I call the sleep lab to ask for the raw NPSG data, what exactly do I ask for?

Have them print up some representative 30 second epochs and then take a bird's eye view from some 300 second epochs. Better yet, see if their software package can calculate "REM Density".

An example of this phenomenon can be seen from this poster:

viewtopic/p401070/viewtopic.php?f=1&t=4 ... m+#p401070

[robysue]

That makes me think that when TB and PP are intervening at the same time, its for variability outside of that "normal" range.

I do not believe that is possible in this configuration, and that the EPAP Algorithm resorts to the classic Popt - Pcrit - Pther approach for obstructive event identifiaction and treatment.

NM, could we trouble you giving us a primer on that classic Popt - Pcrit - Pther approach for obstructive event identifiaction and treatment the Resprionics machines use? Thanks.

[ozij]

That makes me think that when TB and PP are intervening at the same time, its for variability outside of that "normal" range.

I do not believe that is possible in this configuration, and that the EPAP Algorithm resorts to the classic Popt - Pcrit - Pther approach for obstructive event identifiaction and treatment.

NM, could we trouble you giving us a primer on that classic Popt - Pcrit - Pther approach for obstructive event identifiaction and treatment the Resprionics machines use? Thanks.

http://sleepapnea.respironics.com/techn ... rithm.aspx

Proactive Performance
As the chart shows, the REMstar Auto algorithm can determine the optimal therapy level by proactively performing two types of tests (Pcrit and Popt). These tests not only help maintain pressure at a level in which obstruction is unlikely to occur, they also ensure that the pressure never becomes unnecessarily high.

[Paper_Nanny]

Last night, I set Max and Min PS at 0. Max Pressure, EPAP max and min to 8. BPM off. Near as I could figure, this functionally turned my ASV into a CPAP. Please let me know if I am not correct in this figuring.

Here are the results.



And the waves: https://docs.google.com/viewer?a=v&pid= ... z&hl=en_US

edit #1 to change mistyped "EPE" to "EPAP" in first line.
edit #2 to remove broken link to the waves.
eit #3 to insert functional link to the waves.

[dsm]

This will make edit number seven on this post. For some reason, when I posted it before, I was getting a 500 Internal Server Error. It took me multiple posts to narrow down the source of the problem. Problem source was listing all the settings on my machine. I don't know why there was a problem with them, but ha! There you go! For some reason, it was a problem. Thus the writing out of things that would typically be abbreviated. Sheer insanity, in my opinion!!

<snip>

Deborah,
This I think is a known problem. Have certainly had it happen a lot until someone else (Wulfman ?) highlighted that any character sequence that resembles the database code called SQL, can be incorrectly interpreted by the server as database instructions which it tries to run & crashes the session.

Am sure one of the regulars can recall this problem.

DSM

[Mr Bill]

From 4:24-4:54am its both TB and pressure pulses like clockwork.

I think one needs to pay careful to the nomenclature. There are no "Pressure Pulses" per se.

Oh, I think I see. You are saying that pressure is ramped up and down in deliberate increments determined by the algorithm and timing and the flow detected. Its not an uncontrolled pulse. Is that the right way to think about it?

[StillAnotherGuess]

Please let me know if I am not correct in this figuring.

Your figuring is correct.
Your machine was properly configured for CPAP (only) mode, last night.
How do you feel today?

[Paper_Nanny]

This I think is a known problem. Have certainly had it happen a lot until someone else (Wulfman ?) highlighted that any character sequence that resembles the database code called SQL, can be incorrectly interpreted by the server as database instructions which it tries to run & crashes the session.

I figured it was something like that. It is one of the eternal mysteries of the insect world why sometimes I have posted the whole sequence of settings with no problem and yesterday, I had to take out the vast majority of the setting before the post went through.

Deborah

[rested gal]

there is also the preaforementioned issue of the breathing irregularity of phasic REM. And I think that as the REM-suppressant medication effect wears off in the latter part of the night, you have a pile of it (that might be an interesting thing to look for in your raw NPSG data).

When I call the sleep lab to ask for the raw NPSG data, what exactly do I ask for?

Have them print up some representative 30 second epochs and then take a bird's eye view from some 300 second epochs. Better yet, see if their software package can calculate "REM Density".

An example of this phenomenon can be seen from this poster:

viewtopic/p401070/viewtopic.php?f=1&t=4 ... m+#p401070

And... maybe ask them to give you a DVD copy of your entire sleep study. If they tell you there's no point in doing that 'cause you won't be able to read it without the software that was used by them during your study, ask them kindly to please copy it to a DVD anyway, and send it to you. You like shiny souvenirs.

[dsm]

Deborah,

I am impressed with the waves pages - must admit that ability to display data to that level of granularity slipped under my radar. Is this built into the Respironics software or is this out of one of the software projects I have noticed being talked about on the forum ?

It sure helps with identifying turbulent periods of respiration.

Re your main chart, I notice again a lowish Av Tidal Volume. The CA's are obviously needing professional interpreting as they seem excessive. It seems to me your pressure setting was not so high as to be a suspect trigger for them.

But, the 64k$ Q is - how are you feeling (any trace of headaches ? ).

DSM

#2
See this link & look at the section on hypocapnia - http://www.buzzle.com/articles/carbon-d ... blood.html
- any match of symptoms there ? - the headaches are usually associated with hypercapnia (too much CO2) & I imagine if this were the main issue I'd expect to see a lot more hyper ventilation / fast breathing / higher av tidal volume or possibly high blood pressure. Your repeated tendency to CAs Hypops etc: leans me towards hypocapnia symptoms (too little CO2).

Do you experience cramps of any sort when you have sleep arousals ?.

D

[NotMuffy]

This I think is a known problem. Have certainly had it happen a lot until someone else (Wulfman ?) highlighted that any character sequence that resembles the database code called SQL, can be incorrectly interpreted by the server as database instructions which it tries to run & crashes the session.

I figured it was something like that. It is one of the eternal mysteries of the insect world why sometimes I have posted the whole sequence of settings with no problem and yesterday, I had to take out the vast majority of the setting before the post went through.

Deborah

I have trouble when I want to post U/L and D/L, but put an "s" after them to make them plural. It don't like that.

[NotMuffy]

BTW, I am not a big "Auto" breath rate fan. When it first came out, it defaulted to a rate of about 9. That didn't work out very well.

The new multi-layered algorithm relies heavily upon exhalation time. While it can work well in treating what it was designed to treat (chain centrals), once one starts using this thing for stuff other than it was designed for (especially relatively normal breathing), I believe short exhalation times will make the algorithm "pushy".

[rested gal]

Re your main chart, I notice again a lowish Av Tidal Volume.

If Deborah's is low (440 for that night), mine is too -- and I don't have any health problems (other than mild OSA and mild PLMD.)
For over a week on an S8 VPAP Auto 25, my 95th% tidal volume was: 400, 340, 340, 380, 340, 380, 340, 340, 360, etc. The mean was almost always 300, occasionally 320, and as low as 260 one night.

Of course, tidal volumes that seems to do ok for me aren't necessarily right for Deborah or someone else.
But anyway... "To each their own" -- tidal volume, among other things.

The CA's are obviously needing professional interpreting as they seem excessive.

Well, ummm, that is one of the many things NotMuffy is looking into ... and will be looking into further when Deborah is able to get the NPSG raw data he requested.

there is also the preaforementioned issue of the breathing irregularity of phasic REM. And I think that as the REM-suppressant medication effect wears off in the latter part of the night, you have a pile of it (that might be an interesting thing to look for in your raw NPSG data).

You probably want to leave the variability of phasic REM alone (including centrals that are in there. They are generally considered to be normal phenomenon.)