Kiralynx wrote:
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My understanding is that the algorithms in the ASV were originally developed for congestive heart failure. Is this correct? Oversimplification? Or is this a case of "insufficient information to ask the right questions"? (After all, if you ask the wrong questions, you are not going to get the correct answer for what you thought you were asking. You will get the answer to the question you asked.)
I'm tired enough right now, even with about 7 hours on my ASV, that I'm not parsing the abbreviation NOX. Pulse oximeter? I am pushing for an official one with official downloads.
Apologies if my typokinesis and homonymitis has run rampant in this.
KiralynX,
The ASV 'algorithms' are actually not super complicated. I regard an advanced Auto as being more complex. My own confidence in the ASV (esp the one you have) is how flexible it is & if I were in a situation like yours, I would have the confidence (along with measurements such as SpO2) do do something even if it was to prove that cautious replication of what was applied in hospital, helped calm my mother. I would never advocate action outside a doctors advice unless it was clear that help was not available.
Muffy-SAG means well with his detailed advice but it only means something if you can follow through and have the support to see it followed through. I am reading that this is not quite the case. Anyway, I am not at all saying go and slap on the ASV without a good plan.
How the ASV works is this ...
1) It basically operates as a bilevel delivering 2 pressures - that is easy for most of us to follow. It does have an extra setting of a third pressure called Ipap Max that Ipap can be lifted too if needed ...
2) It has a timed mode and sensors to track breathing rate & peak volume (that is, the bipap SV) so if the tracked BPM drops below a back up rate (or a tracked rate) it will activate the epap to ipap to epap cycling at the back up rate BUT, as distinct from a timed bilevel, the ASV has a trick up its sleeve, as it cycles it is able to keep bumping up the ipap pressure (2-3 CMs per breath for max 3 breaths) which means that if the sleeper hasn't resumed 90% of the peak tidal flow it was tracking, it keeps upping the pressure (maxes out after 10 CMs) as that is pretty certain to get the sleepers lungs working again within 3 breaths. Then the ASV will very very quickly lower the ipap pressure once the target flow is back on track.
What I just described in 2 above is the waning side of the CSR cycle and or a Central (which usually follows the waning phase). It is safe to say though, that this approach actually pre-empts a central / reduced flow & under most typical circumstances breathing remains to within 70-90% of the prior tidal flow because the machine can detect a looming missed target within 1 breath and boost ipap upward as much as 3 CMs in the one breath.
3) If the sleeper starts to hyper-ventilate (waxing phase of CSR), then the Bipap SV will resume the initial epap & ipapmin settings (it drops the ipap to the minimum gap set between epap & ipap) and (IIRC) will slow the epap/ipap cycle. Other brands such as the Vpap Adapt SV & the Sommnovent CR appear to have additional ways of controlling the waxing phase of CSR.
There is no hidden 'magic' in the ASV box. It is in its simplest form a bilevel with some fairly straight forward extras that allow it to normalize or smooth out the fluctuations in tidal flow that are obvious in a CSR patient. It does look for and recognize the 'patterns'. The ASV does not perform magic of voodoo on the user (Muffy take note!), it just helps smooth out the users breathing. The critical factors are setting the right epap, then the right epap to ipapmin gap & also being cautious with the ipapmax setting that it is not too high for the patient it is applied to. ASV are not a dangerous drug and using them is not a black art even if some would have us believe it is.
God bless & hang in there
DSM
#2 PS on the issue of Oxygen, if you can't get this attended to via the medical system, I would lean towards measuring your mother's spo2 with your probe & printing the data . Remember it can be taken from the toes as well as the fingers & a big toe can sometimes be less of a hassle. If it were my mother & I had no other avenue I could see to get help. I would use the ASV with cautious settings (similar to what they used in the hospital) & ipapmax set 9 over ipapmin, & then compare the SpO2 readings when being ventilated. If her SpO2 shows desats without ventilation but is ok with ventilation then you would have a very meaningful answer.
(To muffy, if the above comment induces a compulsion to swear please just PM it to me & spare the other readers/posters).
D