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Weinmann / Löwenstein Prisma 20A Auto CPAP: APAP settings: standard vs. dynamic
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Weinmann / Löwenstein Prisma 20A Auto CPAP: APAP settings: standard vs. dynamic
A few days ago, TBMx wrote a post... in another thread of mine:

"well ... as I said: I have not read anything about the difference of these 2 modes (or that there are this 2 modes)


I only know this because I was asked once (one single time!) if I know anything about that.

this is a Screenshot from PrismaTS (obviously in german) which shows the setting - I would translate it to sth. like "APAP control" or maybe "response"
 

If I would have to guess my money would be on making the response a bit "faster" - leaning towards how the AutoSet-Algorithm of ResMed works .... but once again: I have never seen this "in action" or read anything about it at all. ... could be very well that it does the opposite and leans more towards the "For Her" Algorithm.
(I took the ResMed-Modes just for comparison as they are very well documented)

I just pointed this out as you seem to be still in the "trial-phase" ... maybe you can figure this out and bring some light into this...

BTW: I really like your posts and how you share and describe your findings with the prisma [Image: thanks.gif]
this really is "one of a kind" thread about the H+L Prisma. "...

Cool

This was the beginnig of my search in the Internet for information - trying to bring some light into this - about the (unknown to me - until this post) 2 available APAP settings of Weinmann / Löwenstein Prisma 20A Auto CPAP, the CPAP I'm using...

The first thing that crossed my mind was to go and check if these 2 settings were available in my CPAP and... yes!... they were, so I switched from std (standard) mode to dyn (dynamic) APAP mode...


Well, this was the easy thing to do...

I'm using this APAP mode for the last 3 nights. I can not tell the difference, since I changed my high pressure setting from 14 to 16 cmH2O, and the softPAP from 3 to 2. I hope - as usual - only time will tell, if this setup fits better my treatment, but... this is not the point of this thread.

The point is that I could find absolutelly no information on these settings over the Internet. I called Weinmann Biomedical Engineer, who is taking care of my needs - as a Weinmann client / end-user, asking him about these settings. His initial reply was that most probably, according to his professional experience, dynamic setting should be a "faster - more agressive algorithm, trying to deal faster than standard algorithm with apneas during the patient's sleep with the CPAP / APAP machine".

Although he tried to find something about this in his Weinmann manuals etc. he came up with no result, so he promised me, and he did so, to send Weinmann an e-mail, asking them more information on this subject. He told me "I will let you know, as soon as I have any reply"...
I thought this would take some time, although I doughted Weinmann would reply - and even if they would... this could take "some" time.

Well... I was wrong!... This evening I found an e-mail from Weinmann Biomedical Engineer, with an attached Powerpoint file from Weinmann, presenting - among other things the: prisma 20A APAP settings: standard vs. dynamic.

At this point, I must agree with the comments of another member of this forum who wrote that manufactures seem to consider their Dealers as their clients and not us... the end-users of their products. I'm saying so, since I've sent an e-mail to Weinmann, asking them permission to use their software: prismaTS and also issue a legal copy for any user of this forum that might be interested, but... still I haven't received an answer, although it's been more that three weeks eversince...
Anyway...

I kept the important pages of this presentation of Weinmann / Löwenstein Prisma 20A Auto CPAP: APAP settings: standard vs. dynamic and here they are:

[Image: 1IPbdsj.jpg]

Here there's a general explanation of how to chose the right APAP setting... according to each patient's needs.

[Image: U9h8vWv.jpg]

In this page, they explain - in the graph - the way each setting is working, showing the "steeper" or "faster" or... more "agressive" way dynamic APAP setting is working vs. the standard setting. It is really interesting to see that this is explained during a series of periods - the actual periods of our sleep... and how each setting is "dealing" with each "case" like: oA, oH, RERA, flow limitations, no events and... snoring!...

[Image: gFlaDpE.jpg]

Then follow a couple of pages, explaining which are the reasons for increasing minimum Pressure, and...

[Image: chGdRT7.jpg]

... which are the reasons for decreasing maximum pressure, based of prismaTS therapy analysis and reports from PG monitoring. All this information, with simple, easy-to-follow graphs. These explanations are necessary in order to understand the "mechaninsms" of the APAP function.

[Image: KnIWxno.jpg]

Based on the previous explanations, follows a page showing in a comprehensive table, the standard and dynamic settings, and on which "case" each setting is recommended for.

Here, things become more clear, as the following pages desrcibe how each setting's algorithm is working, this time with numbers.

[Image: rm3ixgt.jpg]

First is explained the standard APAP algorithm with examples for each "epoch" (with a duration of 2 minutes) of our sleep, named eSO (severe obstructions), eMO (mild obstructions) and eFL (flow limitations of breath). It is showing the amout of events that must be "counted" by the algorithm, in order for the CPAP to start "taking action"...

[Image: 0esbHwP.jpg]

Then comes the dynamic setting, which for the same "epoches" the algorithm is activating the CPAP much faster, by "counting" fewer events per epoch, trying to "resolve" the event earlier than the standard setting. Looks like it is trying to prevent an event as soon as "it" discovers it. The only thing here is how accurate is the prediction of the forecoming event, but... 

[Image: j23cGe1.jpg]

this is taken care of the FOT function. What is this?... It's the "prediction of events" tool the CPAP is using, in order to "trigger" the APAP algorithms (std or dyn) to "take action".

The presentation concludes the APAP settings topic, with an APAP algorithm example... in details...

[Image: UP4IPzR.jpg]

... showing with numbers, how the APAP is really "dealing" with each "epoch" which is devided into 4 Quartiles, and the increase of pressure needed for series of events (eSO, eMO, eFL) in order to normalize the breath of the patient.

I found this presentation really explanatory and at the same time easy to understand. It really helped me understand the value of each setting, and according to my Weinmann Biomedical Engineer's experience, it seems that dynamic APAP setting should serve better my apnea treatment.

At this point I should mention a "slight detail" - if I may say so...

Weinmann is using a full time pressure turbine, meaning that the turbine is working continuously at full speed, producing full pressure, while the amount of pressure released to the patient is regulated by software driven valves, giving the CPAP a faster response time, over other CPAP manufacturers that are addressing this issue by increasing / decreasing the speed of their turbine, in order to catch up with the necessary pressures, usually issued in "beats" of air flow, instead of continious flow variations which prisma 20A is doing.

[Image: nJ2MtGf.jpg]

This is clearly shown in the graphs in the study I've already posted in this forum, conducted by a Spanish University. The graph above is showig this function of prisma 20A Auto CPAP.

As a user I can tell that this continious "full throttle" turbine operation of prisma 20A is giving as result a very quiet operation, since it's impossible to hear the turbine going up and down while attempting to produce the necessary anount of pressure each time. Also, there's no feeling of sudden increase or decrease of air pressure, since this is done very smoothly and, of course, without any noise from the turbine.

This is one thing I didn't like on Respironics System One - 60 series C-Flex Auto CPAP  that I tried, before I buy this CPAP that I'm using now: Weinmann / Löwenstein Prisma 20A Auto CPAP.

I think in terms of comfort (ease of breathing and noise) prisma 20A is well ahead of System One. Also, due to this continious flow of air, the prisma 20A doesn't ever give the impression that your breath is "following" the machine (trying to catch-up it's pump), but rather that you're breathing "with" the machine, without making any effort at all.

I hope this thread will help us all understand how APAP mode is working, since basically I think all the CPAPs offering APAP function are using, with different approaches. Different algorithms used and different ways of air pressure production and manipulation.


Costas
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RE: Weinmann / Löwenstein Prisma 20A Auto CPAP: APAP settings: standard vs. dynamic
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Thanks for discovering this goldmine, not found elsewhere.
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