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PrismaSMART and artifacts
#1
PrismaSMART and artifacts
Hello all,

I face a strange problem with the device PrismaSMART. The sleep-data shows more or less artifacts for the entire time of the therapy. The insurance replaced the device after looking at the data saying the device could be faulty. The new device however displayed the same problem. This was the case for almost a week where I tried several things and one day the artifacts disappeared. The only change I did was to no more keep my cellphone anywhere near the CPAP device during the therapy. I haven"t changed anything else on the device or the mask. I really thought that the EMF from the cellphone was creating the interference (the user-manual of PrismaSMART also says that the cellphone could interfere, but I did not see anyone ever reporting such an issue). A few days later the artifacts appeared again (not to extend as before). Now I kept my cellphone back near the device and the artifacts haven"t increased (as it was the case in the beginning). See attached pics. Does anyone known why the device showed data as noise and still shows at times? Has anyone faced a similar problem with any other device?

Cellphone near the device
[attachment=7902]
[attachment=7901]
[attachment=7903]

Cellphone away
[attachment=7900]

Regards,
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#2
RE: PrismaSMART and artifacts
It appears with the cell phone close to the machine the "obstruction" (same as flow limitation) is recorded as an inverse chart most of the time. This may be what is being flagged as an artifact. Interesting that the flow limit drops when leaks (rMV) are high, and this probably reflects the inability of the machine to detect flow limitation when large leaks occur.

Overall, your AHI is acceptable, with occasional clusters of OA and H, and those events seem to line up with higher flow limits. Your leak rates are too high and there is excessive flow limitation. I think you might benefit from a soft cervical collar to prevent your chin from tucking toward your chest which obstructs and restricts your airway. A soft cervical collar can prevents these obstructions and help with the leak rate by applying pressure to your jaw to promote a closed position.

Your machine also has an exhale relief feature, and it is unclear if you are using that with your pressure settings of 9-13. Given the amount of hypopnea and flow limitation, exhale pressure relief may be helpful, but may require a higher minimum pressure.

I have no answer to the artifacts on your machine other than suggest you keep your phone away if that is a source of interference. You do need to deal with leaks, and might want to consider the positional therapy of a soft collar, and using pressure and pressure relief to improve results.
Sleeprider
Apnea Board Moderator
www.ApneaBoard.com

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#3
RE: PrismaSMART and artifacts
Thanks a lot for your reply. I really appreciate your help here.

Most of the elements in the sleep-data is self-explanatory for me, except for rMV (relative Minute Volume) and unintended Leak. I always thought "unintended Leak' is the one I have to watch out for as this is the real leak. The software that I use (PrimsaTS) says that I am completely green w.r.t leaks (2.5l/min). You have mentioned that the rMV is quite high in my case and I could adopt the measures you suggested. Do you mind explaining the relation between obstruction (flow limitation), rMV and unintended Leakage?

Regards,
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#4
RE: PrismaSMART and artifacts
The best (and only) explanation of the Prisma algorithm is here http://www.apneaboard.com/forums/Thread-...vs-dynamic

One unusual feature of the Prisma algorithm is that the high pressure limit (Pmax) effects operation even when the pressure is much lower, as the machine changes response to events depending on which is the quartile (between Pmin and Pmax) of the current pressure. The nearer the current pressure is to Pmax, the "softer" the response. 

In Std mode, The machine does not respond to flow limitation at all when the current pressure is more the lower quartile which is most of the time.
This is why you see nights full of flow limitation obstructions without the machine doing anything. Nothing to do with your cellphone.

If you like a more aggressive response to flow limitation obstructions you can set the machine to Dyn mode and/or set Pmax higher.
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#5
RE: PrismaSMART and artifacts
Thanks for the detailed technical explanation. That still somehow doesn't solve the puzzle. The flow-limitations (Obstructions) shown I guess  ain't really limitations. It is some-how inverted (see the white-parts which are under the brown-part of Obstructions. It should have been brown through-out from 0 to 100). Also, if the flow-limitation is so continuous, I wouldn't be really living now to write this I guess Smile There are no leaks at this time to show that I was breathing through the mouth (to allow me to live).
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#6
RE: PrismaSMART and artifacts
(08-29-2018, 08:30 AM)nirmal Wrote: if the flow-limitation is so continuous, I wouldn't be really living now to write this I guess Smile

Flow limitation is not apnea or hypopnea, you do not stop breathing. You do breath but the breath flow is limited and hits a plateau, hence the name. It's entirely possible to breath flow-limited most of the night without any consequences. For some people it's a problem and for some it's not, hence different machines respond very differently to flow limitations.

Could you post a zoomed-in screen of the where the screen width is about a minute of the flow limitations?
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#7
RE: PrismaSMART and artifacts
(08-29-2018, 08:38 AM)yrnkrn Wrote: Flow limitation is not apnea or hypopnea, you do not stop breathing. You do breath but the breath flow is limited and hits a plateau, hence the name. It's entirely possible to breath flow-limited most of the night without any consequences. For some people it's a problem and for some it's not, hence different machines respond very differently to flow limitations.

Ah ok. I interpreted it differently.

Here's a 10 min and 1 min view.

[attachment=8015]
[attachment=8016]

Thanks a lot for you help.
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#8
RE: PrismaSMART and artifacts
These flows do look limited but it's hard to see - could you zoom the flow horizontally so that the flow fills most of the yellow band?
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#9
RE: PrismaSMART and artifacts
(08-30-2018, 02:06 AM)yrnkrn Wrote: These flows do look limited but it's hard to see - could you zoom the flow horizontally so that the flow fills most of the yellow band?

Do you mean this way?
[attachment=8017]
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#10
RE: PrismaSMART and artifacts
No, sorry, I meant vertically.
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