Replaced my ASV, not happy, need help

[Sleeprider]

The mask pressure graph suggests that pressure support is happening, even where the pressure graph shows only EPAP pressure (green line). Pressure supported breaths of about 7 or 8 cm are shown at your normal rate (bpm) at 04:53 through 04:57. At no time is this a flat PS. This chart is not organized or sized in a way we can judge the synchronization of the flow rate with mask pressure, but it looks like there might be a problem with pressure support being triggered too soon (during expiration).

[bemused]

This is fascinating -- and begins to make sense. I thought it must have something to do with the algorithms. But I agree it's not leak related--because there were minimal leaks when the whole "flat spin" took off:
   

And a closeup of the flat spin:

   

It does look to me like the mask pressure matches the pressure drops, which fits your explanation. It also shows the drops in respiratory rate, down as low as 4.2, compared to my normal of 12-13.

So this all  begs the question -- if not leaks, what does set it off, and how can I keep from doing it? Whatever it is I wasn't doing it before I changed machines, and I'm mystified what started it.Either way, I will try making the PS range smaller tonight (with "old" machine) and see what happens.

So I probably didn't need to change machines -- but in a moment of weakness I gave the serial number to my respiratory therapist so she could link it to their system, and I realized later (especially after watching the Frontline show on AI) that wasn't such a good idea, so maybe just as well. . .

[WillSleep]

This is fascinating -- and begins to make sense. I thought it must have something to do with the algorithms. But I agree it's not leak related--because there were minimal leaks when the whole "flat spin" took off:

" not from leaks, ...  something to do with the algorithms."

Yes, ASV Algorithms plus a EPAP Min too low at 4.0.

First cycle ( (from you flow limitation/resistance) + (EPAP Min too Low at 4.0 )  + (ASV using all available of PS Max, far beyond what it could recover from gracefully)  + (hypopneas from your recovery to such massive pressure swings and the ASV algorithm gaps at that point))   

Second and remaining cycles ( (everything above) + (now in addition to providing Flow Limit/Resistance you are also quite understandably, normally a little off after such large sudden pressure swings) .. and so the cycle continues. 

How much impact did raising EPAP Min have on abrupting this pattern?  We have not seen many recent charts.  Did this pattern from the 30th continue with a higher EPAP Min or become less of an issue?     

WillSleep

[WillSleep]

"But I discovered something weird, which is that the machine keeps dropping the PS below the set minimum, sometimes down to zero." - bemused

this was jaswilliams' response when I asked about this:

"The pressure support line dropping to 0 Is a data issue coming from the Resmed.

If you look at the mask pressure line you will see the pressure support is still at or above the minimum values. This issue has been observed elsewhere nothing you can do about it"

If you want, as is the norm for folks that move pretty to find an answer.   We could help more & better if you post more recent daily charts and a few 2 min charts from last night or the next night, etc.  

Up to you.

WillSleep

[sheepless]

I don't have the knowledge to reply to your questions bemused.  for the good of the order, I've tried to reorder graphs and add minute ventilation and at a closer scale.  pretty squashed but maybe useful to the experienced types.  if not, let me know and I'll reorder / size again to some other spec.  probably not important but note that these shots are in SH 1.0.0 beta 2 and that for some reason time is off by 1 hour.

[sheepless]

" Did this pattern from the 30th continue with a higher EPAP Min or become less of an issue? "

I haven't spent much time looking at this but it's sporadic and so far doesn't seem to present a pattern. I haven't associated it with pressure or leaks or anything else for that matter (yet).

I want to add to this thread if useful but do not want to sidetrack / hijack it so I'll leave it to bemused. IDK if her charts look same or different.

[WillSleep]

I've tried to reorder graphs and add minute ventilation and at a closer scale.  

Thanks Sheepless!

Through that time your Min Vent was pretty stable but without the Green line cant tell what the value of Min Vent was at that time.  

If you don't mind, in the chart you just posted generally what value was Minute Vent for that time period?

Thanks
WillSleep

[sheepless]

really really hard to see but the minute ventilation line runs along the median dotted line. med is 7.75. I can post a different pic if you tell me what to show.

[WillSleep]

Thanks.  You fully answered the question.  
 
Minute Vent of 7.75 at the low Respiration Rate of 7.  
 
Tidal Volumes up near 1000mL at that time.
 
Nice!  
 
You look like a good candidate to apply to join Sleepriders "Whale Lungs Club".
 
 
WillSleep

[bemused]

This is fascinating -- and begins to make sense. I thought it must have something to do with the algorithms. But I agree it's not leak related--because there were minimal leaks when the whole "flat spin" took off:

" not from leaks, ...  something to do with the algorithms."

Yes, ASV Algorithms plus a EPAP Min too low at 4.0.

First cycle ( (from you flow limitation/resistance) + (EPAP Min too Low at 4.0 )  + (ASV using all available of PS Max, far beyond what it could recover from gracefully)  + (hypopneas from your recovery to such massive pressure swings and the ASV algorithm gaps at that point))   

Second and remaining cycles ( (everything above) + (now in addition to providing Flow Limit/Resistance you are also quite understandably, normally a little off after such large sudden pressure swings) .. and so the cycle continues. 

How much impact did raising EPAP Min have on abrupting this pattern?  We have not seen many recent charts.  Did this pattern from the 30th continue with a higher EPAP Min or become less of an issue?     

WillSleep

Actually the min EPAP was 5 pretty much the whole time, including the good nights -- except the night of the tail spin -- sorry, at this point no idea why I lowered it that time. But that was the worst night, so what you are saying is making more and more sense. Must confess that the reason I haven't posted last few charts is because I got so frustrated I turned the machine off Sunday and Monday nights, and didn't use it last night. But I will tonight, with these settings, and post the results tomorrow:
EPAP min 5 max 8
PS min 4 max 9