Auto SV User Needs Help

General Discussion on any topic relating to CPAP and/or Sleep Apnea.
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palerider
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Re: Auto SV User Needs Help

Post by palerider » Thu Feb 11, 2016 2:06 am

q49q49 wrote:Can you point me to any tutorials to help me understand how this all should work? I think I understand basic CPAP. I don't understand how "plain vanilla" BiPap works well enough to explain it to my husband. The Auto SV seems like fuzzy logic. I'm looking forward to getting Sleepyhead installed and to start looking at data. I'm an ex-engineer and my husband is a technical person too. If I can explain to him what the machine is trying to do, it will go a long way to help him adjust to it.
I'm not sure about any handy tutorials, and I'm also not sure which "this" you mean in the first sentence... however,

basic plain vanilla bilevel (bipap from respironics, vpap from resmed) is VERY simple... *ALL* that means is that there are different pressures for inhaling and exhaling, for instance a setting of 14/10 means 'when inhaling, the pressure goes to 14, when you exhale, the pressure drops to 10". that's all there is to it. it makes it easier to inhale and exhale, you've got a bit of a boost for the inhalation, and it's easier to exhale against the lower pressure.

I'm not sure if I'd call the autosv fuzzy logic or not, (I'd have to go remind myself exactly what that means) but what it does, essentially, is calculate what the average minute ventilation is for the user, and then if it sees that starting to drop, it increases the inhale pressure, sometimes by a lot, to basically force air into the lungs.

lots of newbies get all hyperbolic about their cpaps "forcing air into them"... something cpaps NEVER do... AutoSV machines, however, actually DO do that, which is how they treat central apneas.

I thought I'd seen a video on youtube about what ASV (what respironics calls autosv) and how they work, but I can't find it... I did find this info that may be helpful
https://www.resmed.com/assets/documents ... ow_eng.pdf

also, while it may be overly technical (y'all will have to judge) I found these, about ASV in general:
https://www.youtube.com/watch?v=P1lrr0BrE94
https://www.youtube.com/watch?v=d35qx0A3PAg
the guy has a fairly heavy accent, but there are english subtitles.

also, here's a video I saw that I'd watched sometime back when I was educating myself on bilevel theory: (also rather technical)
https://www.youtube.com/watch?v=A-SlO2dU8Og
as well as this one: https://www.youtube.com/watch?v=BdeOiDJmbrk

let me know what other questions you have

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JDS74
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Re: Auto SV User Needs Help

Post by JDS74 » Thu Feb 11, 2016 6:33 pm

q49q49 wrote:The study report does include a spreadsheet that shows the response to various combinations of EPAP level, IPAP level, and Pressure Support level. Response recorded appears to be Periods (# of), Total time, Sleep time, % Sleep, %REM, %nonREM, # of CA, OA, MA, Hypop, and A+H, AHI/h, #RERA and RDI/h. He never got to REM sleep. No notes anywhere indicating if any of the combinations was better than any other. It really looks like they punted and just prescribed the factory numbers.
That is the correct section of the report:
So: could you post a little table that looks sort of like this?:

EPAP____IPAP___Pres Supp____#CA___#OA___#HYPOP___AHI/h
Then fill in (separated by underscore characters) the values in the report. One line for each change in any of EPAP, IPAP, Pres Supp.
From there maybe we can figure out why the default parameters were used and what might a good set of values might be.
q49q49 wrote:Is there a previous post that you would recommend as a crash course into what the data means and how to they relate to one another?
Let's take a look at your settings and see how they work on a Respironics ASV machine.
Actual EPAP supplied is the sum of the current EPAP value which can vary between Min and Max. Current IPAP is the sum of the current EPAP and the current PS values.

EPAP Min-4.0_______This is the minimum EPAP pressure to be supplied
EPAP Max-15________This is the maximum EPAP pressure to be supplied
PS Min-0___________This is the minimum added pressure to get to the actual current IPAP
PS Max-20__________This is the maximum added pressure to get to the actual current IPAP
Max Pressure-25_____This is the maximum pressure the machine will supply
Rate-Auto BPM______This tells the machine to figure out the current breathing backup rate
____________________from what is happening. That is, how long to wait if your husband
____________________stops breathing because of a central apnea before the machine kicks in.

So, he starts out with EPAP = 4 cmH2O and IPAP=4 cmH2O which is generally not enough pressure to do anybody any good. Also the machine starts out looking like a plain auto CPAP single pressure machine and not a really smart AutoSV BiPap you paid for. Pretty quickly, something like a Obstructive event happens or even an transition central event and the machine kicks in bumping the pressure trying to solve the problem. If this happens as he is drifting off, for some folks, it is disturbing and they feel as if they are fighting the machine. Eventually, your husband does get to sleep and the machine find some values that work more or less and then morning comes.

My numbers look like:
EPMin-13.0
EPMax-17.0
MinPS-7.0
MaxPS-11.5
MaxPr25.0

So I start out with 20/13 for pressures. The 13 cmH2O is enough to keep my airway mostly open and the 20 is enough to really keep it open.

After you get the sleep study data posted, we'll talk more about how to adjust your machine to better fit your husband's therapy needs.

BTW, keep your doctor in the loop about any changes you propose to make. You have to make this relationship into a partnership in which you trust your doctor and your doctor trusts you. It's really important.

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Settings: EPAP Min-10.0, EPAP Max-17, PS Min-3, PS Max-10, Max Pressure-20, Rate-Auto, Biflex-1.
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palerider
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Re: Auto SV User Needs Help

Post by palerider » Thu Feb 11, 2016 9:14 pm

[quote="q49q49"]Can you point me to any tutorials to help me understand how this all should work? .[/quote

here's something else I remembered.. page 28 and 29 of this document go into detail about how ASVs work, it IS written by, and about resmed ASVs (I believe resmed invented the whole ASV concept) but the basic principles apply.

http://www.resmed.com/us/dam/documents/ ... lo_eng.pdf

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q49q49
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Re: Auto SV User Needs Help

Post by q49q49 » Sat Feb 13, 2016 9:08 am

You guys are great. 'This' is starting to make sense to me. I found a very concise technical explanation of PR BiPap autoSV Advanced in the Atlas of Sleep Medicine page 305 while googling things I learned from all the links and videos you shared with me.

https://books.google.com/books?id=LbQKA ... ow&f=false

We hope to get Sleephead installed this weekend. I want to look at husband's real data to check my understanding before moving forward.

However, I have one quick question about the ramp button.
Am I correct that it ramps the actual EPAP up from four to the EPAPmin over a ramp time of 0 to 45 minutes? If so, since my husband's EPAPmin = 4, pressing the ramp button would simply reset the actual EPAP to his EPAPmin, no ramping involved. Or does it do something else in addition? It is more tolerable with the ramp option enabled compared to disabled, but it also just the affect having to wake up and stretch to reach the button.

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OkyDoky
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Re: Auto SV User Needs Help

Post by OkyDoky » Sat Feb 13, 2016 10:53 am

q49q49 wrote:You guys are great. I think 'this' is starting to make sense to me. We hope to get Sleephead installed this weekend. I want to look at husband's real data to check my understanding before moving forward.

However, I have one quick question... What does the ramp button do? If I found the right info, it ramps the actual EPAP up from four to the EPAPmin over a ramp time of 0 to 45 minutes. If that is true, than changing the ramp time on my husband's machine should do absolutely nothing since EPAPmin is set to four. Or does it do something else different or in addition? Pressing the ramp button last night did help my husband or it might have just been waking up and stretching as he pressed the button.
You are correct in your thinking with the initial startup. Now in the situation where something wakes your husband up and the pressure has auto increased to a higher pressure, if he then presses the ramp button it will restart the process back to the 4cm. One complaint some people have with a low ramp pressure is that sometimes the 4cm is uncomfortable and feels like your not getting enough air. If that's the case a little higher pressure on the ramp and minimum would be helpful. When you get Sleepyhead you also need to watch to see if events are happening during the lower pressure. 45 minutes would be a long time to be at that lower pressure. Many of us as we get used to our pressures give up or shorten ramp pretty quickly.
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ChicagoGranny
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Re: Auto SV User Needs Help

Post by ChicagoGranny » Sat Feb 13, 2016 11:38 am

OkyDoky wrote:45 minutes would be a long time to be at that lower pressure.
Or in another way to put the same thing, if hub falls asleep in less than 45 minutes and begins having breathing problems that require higher pressures, the machine will not respond until the 45 minutes have expired. In my case, I fall asleep quickly and would have many apneas in the first 45 minutes. So, I don't use ramp.