Can VPAP ST-A do what ASV does?

I never had a lot of Central Apneas, but the Resmed ASV is the only machine that allows me to get decent sleep. 4 sleep studies and all they said was severe obstructive apneas.

In retrospect, I suspect I was reacting to the cessation in breathing too quickly to measure Central Apneas. There was no real drop in oxygen levels when on cpap, but for some reason the quality of my sleep was substantially diminished and I had to try something to get a good night's sleep. Based upon the tiredness symptoms that disappeared with ASV, I suspect I have always had this problem.

What is distinguishable in my charts is when the ASV machine drops to lower BPM back up rate and starts cranking up the breath by breath pressure, then when the episode is done the ASV machine goes back to normal sleeping BPM with nominal pressure support. These periods last 2 to 6 minutes, mostly, and are also characterized by a progressive drop in minute ventilation and target minute ventilation. There might be one episode per night or there might be six of them. It takes a maximum pressure of about 9-10 for the Resmed ASV to be effective in getting a good night's sleep.

So it appears to be some type of sleep transition problem that is distinguishable from my usual pre-sleep SWJ and wake-up SWJ in that with the usual SWJ I can maintain my own minute ventilation and target minute ventilation and my breathing rate, although lower, varies a lot more. Maybe I'll these troublesome episodes "toxic SWJ".

I could never have figured out to use an ASV machine by looking at my prior charts and oxygen levels. I just had to experiment with Bipaps and ASV until I found what gets me a good night's sleep. Apparently, the "experiment when all else fails" is a valid approach.

I even tried a 2012 Resmed VPAP ST-A IVAPS recently, and that whole constant BPM in IVAPS mode seems to irritate me and disrupt my sleep quality just like the large pressure spread of a BiPaP.

Question: Is there a setting with the VPAP ST-A that might be comparable to the Resmed ASV -- PAC, IVAPS, T, ST, or S?

How does the ASV machine know that the airway is clear??

xxyzx wrote: the ASV machine knows you have CA immediately if breathing stops and the airway is clear

nearly! if the breathing stops it just does its "thing" - no matter if it's obstructive or central because THAT IS THE VERY THING WHAT THESE MACHINES DO!^^ (what it does after that differs a bit depending on the apnea-type)

Is there anything to read up on your "theory" about SWJ developing always into CAs? looks to me like a very typical alphabet-nonsense-guess^^

honestly: I really thought about signing up here - xxyzx is the one keeping me from it.

what ever I want and need I can get or give without signing up ... I don't want to be a permanent part of something that gives such level of stupidity and spitefulness a "home". And yes I call the more than ill advised crap that xxyzx gives away in a dozen to everyone just spiteful - noone is that stupid over such a long time! He's doing that on purpose.

Don't want to be a part of that.

klv329 wrote:Question: Is there a setting with the VPAP ST-A that might be comparable to the Resmed ASV -- PAC, IVAPS, T, ST, or S?

no. different machines, different algorithms, different purposes.

xxyzx wrote:

WickedLoki wrote:How does the ASV machine know that the airway is clear??

=========================

depends on the machine
each has a trick they use to see if there is blockage when you stop breathing
if you stop breathing and they sense the airway is clear they call it an open airway event usually a CA but not always
and they start the machine pushing air in at your RR and Vt to keep oxygen going in during the CA

read more here

http://www.resmed.com/.../resmed-sleep- ... ology.html
The Easy-breathe motor also plays a part in differentiating between obstructive and central apneas using a forced oscillation technique (FOT).

wrong. you *obviously* know nothing about the actual operation of a resmed ASV.

xxyzx wrote: then it decides if it is CA or obstructive
it does this immediately within a breath cycle or so depending on their algorithm
it does not count to ten to declare it an official apnea

If there is an apnea - there is no longer a breath cycle! if there would be: no need to worry^^

there is no such thing as "magically instantly decides" between obstructive and central.

FOT is used by ALL machines - no matter what type or brand - there is simply no other way - some call it something else - the (basic underlying) technique is the same - was the same - will be the same in the future.

Guest wrote:FOT is used by ALL machines - no matter what type or brand - there is simply no other way - some call it something else - the (basic underlying) technique is the same - was the same - will be the same in the future.

no, only resmed and trilogy machines from respironics, the consumer grade things from respironics use another technique, with no oscillation.

that is really interesting, thank you very much.
I searched for the other technique but couldn't find any. Could you please point me in the right direction? Or explain how they do that?

Guest wrote:that is really interesting, thank you very much.
I searched for the other technique but couldn't find any. Could you please point me in the right direction? Or explain how they do that?

respironics doesn't like to document what they do like resmed... but you might find something googling for 'pressure pulse', (and respironics).

this link to an article from another thread has some interesting reading on how various machines function.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4629962/

palerider wrote: respironics doesn't like to document what they do like resmed... but you might find something googling for 'pressure pulse', (and respironics).

tank you very much, once again.

I'm not sure if I understood that correctly or maybe I was too unprecise the first time. But what I was referring to when I said "the (basic underlying) technique is the same" was the assumption all machines increase the pressure shortly and than lower it back again and look if there is a (correpsonding) spike (or reation) in the flowrate. H+L called it OPP (obstructive pressure pulse) on their older machines and it looks like something inbetween FOT and the PP from philips.

As you seem to have some insight please tell me, if what I think is correct:
I thought that the underlying technique lies in the 'fact' that if the airways 'are clear' the rise in the pressure would pump some more air into the lungs (due to the comliance of the lung) - if the pressure drops back that little air flows back out of the lungs - resulting in a change or pattern in the flowdata. Of course the airways themself are 'soft' tissue so their is some sort of compliance too and then you have some 'deadspace' along the way (hose + mask - bigger with FFMs) where rasing the pressure would result in some compression which changes the flow a bit too. So during an obstruction you might or would see an equal pattern as during CA-events but not with the same magnitude.
So aside from the frequency or amplitude / strength of the pulses the technique looks the same.

Thinking about it there might be some advantages and some diadvantages for one or the other implemantation. I have my doubts that a mixed apnea could be detected with (some) PPs alone, a continous oscilation during the whole events looks much more promising in that case. A too high Pulse or oscilation with too much pressure difference could on the other side very well 'clear' some obstructions or produce leaks and make it look like a central apnoe - too low and you might end up seeing just the "deadspace" compression - no matter if the airways are clear or not.

palerider, does that more or less look correct to you - or did I misunderstood that too?

tanks in advance for any response - very much appreciated.

here's some detail about what resmed says they do.

https://www.youtube.com/watch?v=4GW97Xk06N8

you can infer, guess, or possibly dig up something about what respironics looks for with their pressure pulse technique.

my s9 st, doesn't use a pressure pulse and scores both central and obstructive as an unclassified. It score ca and oa in cpap mode with a pressure pulse.
Does the st-a have a pressure pulse to distinguish between the two?