New on Bipap ASV, have a few questions

[Sleeprider]

Your rights under HIPAA, or how to scare the sh*t out of medical practices withholding your records: https://www.hhs.gov/hipaa/for-profession...index.html

[tcolar]

Hi, last night I tried something a  little different, I set my epap very low, but my PS high (hoping it would have a stronger reaction to events)
epap : 4-7 , ps: 6-24, BPM of 10

The results, while still not great, looked better, AHI closer to 5 if removing the early swj.

   

One thing I'm curious about is, it seems from 23:40 to 00:12 I was 100% on machine triggered breath with a very constant 4-14 mask pressure cycle and no events.
Then around 00:13, the machine did not trigger a breath and mask pressure became 407 and that triggered some events.

Any idea what happened there ? does that mean i initiated some breath faster than 10bpm so the machine stopped doing it ? but why dd the pressure drop ?

   

Let me know if you make anything out of that, thank you.

[Gideon]

Note that your EPAP stayed at 4 with very little variance for the entire night. When your breathing was faster than 10 you didn't need as much PS. Your "pressure" is almost all PS. In the close up you were breathing "on your own" when the pressure dropped with EPAP = 4 and IPAP = EPAP (4) + Min PS (6) = 10

[Sleeprider]

This looks better, and since you don't have OA, keeping EPAP low is the correct approach. You may ultimately be able to slowly increase PS max which should clean up the hypopnea. Note at 00:11:00 you are exhaling around the mask (no expiration wave).

[tcolar]

@bonjour, I'm not completely sure where that leaves me. should I set the bpm back to 12 and let the machine do all the breathing, it seems to work better when I'm not the one breathing .... that sounds ridiculous

@sleeprider did you mean increase the PS *min* ? The PS max is already at 24, it does not go much higher than that ?

The machine just seems to be really slow to respond to events, I tried it yesterday by manually closing off the tube ... it takes about six seconds between each increase of pressure and at most goes up by 5 each time.

so for example it will do   4 -7 -4 - 12 -4 - 17 .... say it clears at 17, that would have taken 18 seconds ....., could not find any way to change that

   

[Gideon]

Actually I was thinking of trying a lower Backup rate, you said your natural breathing rate was  9-12, so 9 or 9.5.  I'll say 9 because you are supposed to be returning the machine correct?

[tcolar]

I had been using 9 some of the previous night, that reduced machine triggered count for sure, but ahi was I  worst, that was different settings though, I can try tonight, same settings but with bpm at 9.

I have this machine until Thursday 10/3. let me know if there are other specific things to try while I have it.

[Sleeprider]

@bonjour, I'm not completely sure where that leaves me. should I set the bpm back to 12 and let the machine do all the breathing, it seems to work better when I'm not the one breathing .... that sounds ridiculous

@sleeprider did you mean increase the PS *min* ? The PS max is already at 24, it does not go much higher than that ?

The machine just seems to be really slow to respond to events, I tried it yesterday by manually closing off the tube ... it takes about six seconds between each increase of pressure and at most goes up by 5 each time.

so for example it will do   4 -7 -4 - 12 -4 - 17 .... say it clears at 17, that would have taken 18 seconds ....., could not find any way to change that

If the Auto BPM is what feels best I would stick with that. 

I was mistaken about PS max and didn't realize you had it that high.  The median pressure support now seems to be 6.5 (10.5/4.0) and it ranges up to about 13.0 (18/5).  It looks like you are spontaneously triggering about 70% of breaths, and I don't see a problem with your current backup rate.  At this point, most respiratory statistics look very good, and the hypopnea are the remaining challenge, and I have seen this fairly often with the Philips machines.

[tcolar]

Now I have the Bipap ST, not getting any better results so far (as expected)
Also Oscar seems a bit confused about the pressure and minimum values, OTH this shows way more RERA's, the ASV didn't.

   

One thing I'm a bit confused about, is when I was on the plain abap machine (prior to September), my hypopneas scores were reasonable (~2), but withe ASV and ST they have shot up big time, is it possible that it's caused by the backup rate ??

   

[WillSleep]

Hi tcolar,

I am new here and have ZERO formal training on these topics so in every possible way please accept that what I post in this thread here should be COMPLETELY ignored without follow-up from others.  


TLDR:  Your last OSCAR report says you are using a DreamStation AVAPS.  Have you tried AVAPS? 


I was studying a few of the screen shots where you had zoomed into 3-5 minutes of the Flow Rate.  

I noticed in in a few of your screenshots:

- On the whole it seemed like your Tidal Volume and Minute Volume were to my untrained eye "OK", within reasonable bounds.

- However, I also noticed:

1. What appeared to be a sizable percentage of time at a low Respiratory Rate (7-10).

2. Sometimes in the Flow Rate charts the Volume of your Expiratory Flow (Ve) looks low, like the 90 seconds from 10:00 to 11:30 in this image http://www.apneaboard.com/forums/attachm...?aid=15812  and also from 1:34:30 to 1:35:50 where IPAP and Mask Pressures are not high enough to explain the low Ve in this image http://www.apneaboard.com/forums/attachm...?aid=15758 .   

3. Sometimes in the Flow Rate charts the shape of your Expiratory Flow looks to this extremely novice eye as having:

3a.) A "fast expiratory fall time" (your flow looks to often have is more of a vertical line on exhale rather than the more common line moving up and the right at 30-60 degrees we see in 'normal flow'). 

3b.) The shape of your Expiratory Flow appears to my untrained eye as Concave (rather than the more common line moving "up and to the right at 30-60 degrees" we see in 'normal flow')  

3c.)   Both the 'fast fall' and 'concave' shape can be seen on the same breaths in this screenshot at the probably mis-tagged Hypo flag at 1:36:20 and from 1:37:25 to 1:37:50 in this screenshot http://www.apneaboard.com/forums/attachm...?aid=15758  and also from 11:35 to 12:45 in this screenshot.      


Resulting Conclusion & Hypothesis:  

I have no direct hands on experience from which to draw so I am just working from the available reading.   My untrained take on the reading suggests that:

- Low Volume, Fast Fall, Concave shape in Expiratory Flow points to lung obstruction that comes from things like allergies, lung congestion from the flu, CPOD or other form of emphysema. 

- Philips Respironics and a reasonably broad base of independent researchers, MDs, emergency room ventilation Standard Operating Procedure (SoP) docs and ICU ventilation SoP docs state the treatment protocol of choice would be AVAPS or AVAPS-AE.    

- The ASV algorithm is struggling for you.  Your last OSCAR report says you are using a DreamStation AVAPS.  Have you tried AVAPS?


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I no hands experience with AVAPS but I would love to try one .  

From the marketing AVAPS looks like an orchestration controlling function added on top of one of the more traditional Bi-PAP modes S, A/T, PC and T.   Looks like in theory you get a lot of the same desirable results we like about the ASV just from possibly a little more proactive (hopefully not obnoxious) of doing whatever it takes to ensure that your average 60 second Tidal Volume meets the configured lower limit.  

The slower AVAPS algorithm might be OK when the algorithm is doing more of the driving, in some cases taking proactive action a little earlier than the ResMed ASV would, and maybe sometimes far earlier or more effectively than the PR AutoSV.  However, with AVAPS limited to 2.5 cmH20 of change per minute ... Ya, you sometimes you might miss that ASV responsiveness.   





WillSleep    


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Looks like raisedfist knows something about AVAPS.  He posted this in thread t173964 at [[ Auto Word Filter: links to DME-owned sites not allowed ]] .  I have not checked but he might be a good source for additional comparison information.   

"AVAPS is designed to target an average tidal volume that is programmed by the clinician that supposedly matches the patients ventilation needs. AVAPS stands for average volume assured pressure support. It's designed specifically to treat hypoventilation. What AVAPS does is you set a min and max IPAP, and the machine auto adjusts the IPAP as needed (aka the pressure support since EPAP stays the same as programmed) to maintain the average target tidal volume.

The ResMed iVAPS machine is somewhat similar but its' VAPS algorithm targets alveolar ventilation, taking into account the amount of deadspace (estimated by the patients height) that does NOT contribute to gas exchange. The algorithm in conjunction with a dynamic backup respiratory rate helps maintain a consistent target minute ventilation, even when the respiratory rate changes. Minute volume is the product of RR and Vt, so technically targeting a Vt is only half of the equation.

The ResMed machine is superior in terms of customization settings and build quality, plus the algorithm is much more responsive. However, IMO iVAPS therapy is harder to set up than AVAPS."



Good AVAPS intro video from Phillips (demoing a V60).  https://www.youtube.com/watch?v=49hZ8G_r0IM&t=1s   
AVAPS videos within the last year  https://www.youtube.com/results?search_q...%253D%253D


A few example GoogleQueries:   
[/url][url=https://www.google.com/search?hl=en&q=%22avaps%22+dreamstation+spontaneous+backup+rate]https://www.google.com/search?hl=en&q="avaps"+dreamstation+spontaneous+backup+rate
https://www.google.com/search?hl=en&q="avaps"+dreamstation+titration
https://www.google.com/search?hl=en&q="avaps-ae"+dreamstation+titration  


AVAPS (Average Volume Assured Pressure Support) Notes from the Phillips V60 manual

1. AVAPS mode delivers time-cycled mandatory breaths and pressure.
   
2. Mandatory and spontaneous breaths are delivered at a pressure that is continually adjusted over a period of time to achieve the volume target, VT.
   
3. AVAPS supports use of backup rates.
   
4. AVAPS mode delivers a target tidal volume. It achieves the target volume by regulating the pressure applied. 
   
5. The AVAPS mode delivers time-cycled mandatory breaths and pressure supported spontaneous breaths.  If the patient fails to trigger a breath within the interval determined by the rate control, the ventilator triggers a mandatory breath with the set I-Time.
   
6. Optional AVAPS-AE allows itself to be interrupted by spontaneous breaths.