[CPAP] Beyond ASV with Overlap Syndrome!

[WillSleep]

Dave, your tidal volume looks fine at about 600, the problem is your minute vent being only 6.25 due to a fairly slow respiration rate. The slow respiration rate appears to be due to inspiration time of 3-seconds.  So your sense of difficulty in breathing is not in your imagination.  

 
Hi Dave.
 
I agree with what Sleeprider wrote above. 
 

"the ASV fighting me ..." 

Good news. I believe you might be happier with the ASV with these two changes.  
1) Lower PS Max by 2 cmH20  
2) Lower EPAP Min. 

1) Lower PS Max by 2 cmH20  
The times when the ASV could fight you the most is when PS is at it's Max.  Extensive analysis of my ASV's behaviors showed that the ASV often pushed pressure fast far higher than was needed.  When I significantly lowered PS Max on my ASV to where you could see "Tree-Tops" in the Pressure Chart showing ASV really wanted to keep loading on more pressure found only a kinder and more compliant ASV and saw Zero / no negative impacts to my therapy.
 
 
2) Lower EPAP Min. 
 
High overall Pressure levels are lowering your average Respiration Rate and may cause another time the ASV could be fighting you. 
 
"the ASV fighting me ..."   If these three screenshots include times when the ASV is fighting you then a contributor could be that is that when your Minute Vent drops below your Target Vent and the ASV tries to push your Respiration Rate to 15 bpm the overall pressure IPAP is too high and is holding your Respiration Rate down.
 
Good news. I think you have an opportunity to improve Respiration Rate on the ASV.   Lower your EPAP Min. 
  
I think... 

Your ASV chart images look really nice, low AHI and really smooth but at a cost.  Your overall pressure IPAP is too high and it is holding down your respiration rate.  
 
I reviewed a number of my historic ASV charts and see a pretty dramatic impact to Respiration Rate as overall pressure rises and falls. 
 
In this screenshot your Respiration Rate also looks responsive to total IPAP pressure.  above http://www.apneaboard.com/forums/attachm...?aid=17341
 
In this snip from that screenshot notice how:
- Green bars show your Respiration Rate increases as Pressure falls 
- Red bars show your Respiration Rate decreases as Pressure Increases 
   

I think your current setting of EPAP Min at 8 cmH2O is too high to allow the ASV algorithms operate in their most natural forms. 
 
Recommendation - Try this configuration:    
EPAP 5.5-13
PS 3.5-11 
IPAP 9-24 
 
And then lets look at your charts again.  I expect your AHI to increase and your charts to be less pristine, but who cares if you are getting a better night sleep.  
  
 
Ideally to for the ASV to fight you the least something like the following configuration would be the goal, if this configuration it still provides well the therapy you need. 
EPAP 5-13
PS 3.5-9   (keep dropping PS Max until you see a good number of "Tree Tops" in the pressure chart without felt therapy loss)
IPAP 8.5-22 
 
My original post on how to Tree Top   Tree Topping your ASV's Pressure Support   For sure Tree Topping your ASV without reducing the FELT value of the ASV will help reduce the negative aspects of using the ASV and I think this practice will help more new ASV users find success with the ASV.    

WillSleep

[SarcasticDave94]

Thanks for the input WillSleep, with no sarcasm intended or otherwise. My learning phase of self titration/setting adjustments has expired more or less 1 3/4 years ago. My current settings, excepting the recent setting edits of an addition of 1 to my PS Min now at 4 and the lowering of EPAP Min of 1 now at 8, represent all the more setting adjustments I'm up for on this machine. I'll address getting my pulmonary doc to support me and provide medical necessity to get a ResMed AirCurve 10 ST-A and run it in iVAPS mode. I do appreciate the comment on assist, but I feel the ASV has run it's course for usefulness as my sleep tool.

for reference my settings are as showing in left panel:
EPAP 8-13
PS 4-13
gives IPAP of 12-26

[WillSleep]

I understand.

[SarcasticDave94]

Note I'm not certain I switch to the ResMed ST/A with iVAPS, but if I do, there's settings enough to address my uniqueness...on sleep therapy needs that is.

Note also this is a machine that can EPAP down to 3 but that's a wee lil piddly puff. In the other end Max pressure is 30, a balloon inflation attempt and fail but OK there it is.

[WillSleep]

The ST-A is an impressive machine.  

After seeing how smooth your AVS charts are I would expect you would be able to find a configuration that works well for you with the ST-A.


WillSleep

[SarcasticDave94]

Thanks. I'm determined to go at it.

[SarcasticDave94]

I'll be seeing pulmonary office about this as soon as I can get an appointment.

I will be addressing:

1. Inverse I:E Ratio

2. Lack of setting control for timing on the ASV but available and needed to address I:E issue

3. Questionable minute vent numbers.

4. Included will be complaint that ASV and I are no longer on same page, machine and I are in a combat and I cannot use any more than under 2 hrs.

I'm basing my points to address on discussion this thread already contains. Thanks to all again for input. If something is missing that helps, let me know. If you do, thanks in advance. If nothing else to be added that's fine too. I'm sure this Overlap Syndrome (the ResMed AirCurve 10 ST-A iVAPS machine seems sorta rare too) is pretty much uncharted territory for Apnea Board.

Have a wonderful day normal people.

[Sleeprider]

So far, I have not seen the inverse I:E ratio in the actual flow charts. To find examples of it, you should zoom in to graphs of flow rate, inspiratory time and expiratory time and see where you see crossovers. Confirm that time above zero are actually shorter than times below zero flow. The I:E times on these machines is notoriously unreliable and varies by model.

I have to run and will consider your other issues when I get a chance. The Resmed ASV is extremely limiting in settings, and I think your most compelling argument is within the intended use for each machine. With COPD, the ability to improve and shorten inspiratory time by using iVAPS mode for alveolar vent rate, and use shorter rise time, enables you to protect expiratory time.

[SarcasticDave94]

Start Date 11251.9:
Stated that ball rolling, appointment tomorrow to address and begin THE PROCESS. The ASV to Dave interaction is extreme poor as of now. Very similar dysfunction, in that we're not on the same page, as when I was on BPAP w/o those events though.

[WillSleep]

1. Inverse I:E Ratio

 
Hi Dave, 
 
Just an FYI.    
 
I think the inverse I:E Ratio is pretty common on the ASV.  I see it in charts across a number of users.  Inverse I:E is also not a surprise as the ASV tries to at least somewhat model the "Low Tidal Volume Lung Protective Protocol" and a reduction of CAs.     
 
Reducing the Expiration Time makes total sense as one tool in the toolkit when the goal is to reduce CO2 washout >> reduce CSR and reduce CAs.  

So personally I would not worry too much about the Inverse I:E 
 
WillSleep