OSCAR inconsistency between Lowenstein Obstruction Levels / Flow Limitations?

[WisNaeMe]

[attachment=57713][attachment=57714]Software / Operating System -  OSCAR version 1.5.1  macOS Sonoma 14.2.1 

I’m using a Lowenstein SmartMax APAP machine and on starting to use OSCAR, I’ve noticed there seems to be some inconsistency in how Flow Limitations are represented.  I’m aware that these machines have only recently been added to the supported list and that at this point in time are described as being only ‘well supported’ rather than ‘fully supported’

In data imported from the above Lowenstein machine, FL flags appear to only show up when Lowenstein’s SoftPAP (i.e EPR) is turned ON. 

When SoftPAP is turned OFF - OSCAR shows No Flow Limitations in the Events Chart, though data in the Daily Statistics, the Obstruction Level Graph and the general shape of the Flow Rate wave forms indicates otherwise.  

At the same time, Epoch Flow Limitations (eFL) are displayed as Event Flags (Spans) whether SoftPAP is ON or OFF.

For information, Lowenstein’s SoftPAP settings only go up to a maximum of 2 on this model, described variously as:  0=Off (0 cmH2O);  1=Slight (1 cmH2O);  2=Standard (2 cmH2O).

Question 1:   Is this just some quirk in OSCAR or in Lowenstein’s imported data  …or is it something else?

In all of this I’m assuming that Lowenstein’s ‘Obstruction Level’ descriptor and graph (as displayed in OSCAR) is Lowenstein’s equivalent to ‘Flow Limitation’, (y-axis scale differences aside).  When OSCAR displays FL flags in the Event Chart, there is not a corresponding FL Graph; though these FL Flags do seem to correspond to the peaks on the Obstruction Level Graph and the FL Flags can be displayed in the Obstruction Level Graph …though again, only when EPR is ON.

I appreciate that in the absence of agreed standards and nomenclature that each manufacturer is just ‘doing its own thing’ and from what I understand, Flow Limitation Indices such as Resmed’s are a confection of a number of variables and I would hazard a guess that Lowenstein ‘Obstruction Levels’ (labelled as ‘obstruction level in percentage %’) is maybe similar (but again ‘different’).

Question 2:  Given the above, is it reasonable to assume some equivalence between Flow Limitation and Obstruction Level, or is it more nuanced than that? …or is it all proprietary and so we don’t really know?

Question 3:   As an aside, are the flags in the Event Chart summary interpretations derived by OSCAR from the imported card data, or are they actual indices embedded within each manufacturer’s imported raw data?  From other posts, it suggests that the Event Chart may comprised a mix of both Card Data and OSCAR Interpretations, …would this be correct?

Sorry about the minutiae in all the above, but I find the FL flags (when they show) are really useful in helping keep FLs in mind and for more easily spotting things like positional apnoeas.  When they’re not displayed, it can lull you into a false sense of security.

Attached are two recent OSCAR charts from consecutive days to illustrate the issue described above -

Image 1: EPR off 
Image 2: EPR on

At this stage, I’m just trying to understand OSCAR and address the function level things.  I’m not really concerned about the therapeutic side of these graphs at this point, more just trying to get clear in my head how to work with obstruction levels on the Lowenstein machine, with a view to improving FLs and RERAs next.  I will post in the Main Forum when I am looking for help on those issues - though I’ve still got options to try regards pressures and EPR, before I’ve exhausted my own ideas and need some help.

I can provide Lowenstein SD Card Data if it helps with the above issue.  Just leave details of how and where to send it.

Thanks

[leono85]

I am also having the same question, I have been using the lowestein smart prisma 20 for 1 year with no sucess (waking up every day super tired). My doctor put me constant pressure (and then every month trying pressure up or down in the range of 6 to 9) and the softPAP always have been on. The issue is that I have lots of FL. Maybe I should ask to put it off. 
Did you notice improvement with one option or another? (attached)

[WisNaeMe]

I have only been using my Lowenstein machine for 2 months, so I am very new to using PAP therapy …and so I am not the best person to comment on your difficulties.  From what I understand - while folks on the this forum are curious about Lowenstein machines, there is still not much experience of them, as it is a European brand and not widely used or supported in North America - so you will find more questions here than answers.

My main reason for posting in this forum was to try to get some clarification of how OSCAR works with Lowenstein’s ‘Obstruction Levels’ and how they compare to ‘Flow Limitations’ as used by other manufacturers …and to highlight what then appears to be some inconsistencies in how they present in OSCAR.  My graphs were only there to visually highlight the OSCAR presentational issues I described.

You may get a better response by posting your therapy issues in the Main Apnea Board Forum, where more experienced users are able to advise and make suggestions on how to improve your individual therapy and therapeutic settings.

You will probably need to read the note at the top of this Forum, under ‘Important Threads - How to organize your OSCAR charts’ in order to get the best response from folks on that forum.  The chart you provided does not show all of the key information on the left-hand panel.  If you turn off the calendar it will create more space to show information.  You might also need to turn on the ‘Obstruction Level’ graph (Lowenstein’s equivalent to the Flow Limitations graph), in order to provide the core information that folks need to help you further.

Aside for that -

My minimum pressure started at 4 cmH2O and has gradually been increased to 7 cmH2O with maximum remaining at 20 cmH2O.  I have used SoftPAP at all the settings available to me (0, 1 and 2) and I have not noticed any significant change in the my Obstruction Levels on changes to either pressure or SoftPAP.  It may be that I still need to raise my minimum pressure further for it to have any effect.  I might be that I need more of a pressure differential for softPAP to have any effect - though that’s just speculation on my part!

I did notice that epoch Flow Limitations (eFL) do reduce considerably when SoftPAP is turned on, though the Median, 95% and Max Obstruction Levels seem to have remained fairly constant since I started therapy.

I found that using a Soft Cervical Collar did reduced my Flow Limitations - they were less bunched up, possibly due to resolving some positional apnea / ‘chin tucking’.

I’m assuming that you are using the Prisma 20A.  From what I understand it has an additional SoftPAP setting of 3, which behaves slightly differently from settings 1 or 2, in that it drops the pressure on expiration (as expected), but it also provides a burst of pressure on inhalation.  This is supposed to help with upper airways resistance and so help reduce FL’s, UARS and RERAs.  Have you tried this setting (SoftPAP=3) and did it make any difference?

Lowenstein machines are supposed to have the reputation of delivering good therapeutic outcomes at lower pressures when compared to other machines - more patient comfort than numbers focused.  So some of the problems we are experiencing with trying to improve Flow Limitations might be related to this characteristic.

 

[Macka]

I have been using a Prisma20a for six months. The first time I used softpap I was confused by this flow limitation appearing as well. I don't think it is related to the obstruction graph. You have just as many obstructions in both graphs (although grouped differently) and infact you have more arousal spikes in the second graph despite no flow limitations flagged!

Softpap 3 is quite different in its effect and gives a pressure support of 4 which can make quite a difference to flow limitations. Some explanation of my experience with it here.

https://www.apneaboard.com/forums/Thread...#pid502739

[WisNaeMe]

Initially I was trying to establish why the flow limitation flags didn’t show when SoftPAP was off - and whether that was down to the data intentionally not being sent to the card or possibly an OSCAR bug - but I didn’t get any response to that.

But from the Epoch Spans (eFL) and Flow Rate graph, it’s pretty clear that flow limitations are still there when I turn SoftPAP off.  However, eFL only really picks up ‘peak’ flow limitations so it can be difficult to estimate their overall extent without seeing all the FL flags.

I also came round to the view that the Obstruction Level Graph isn’t a good proxy for flow limitations.  It appears to be a specifically Lowenstein confection and at best, an aggregation of all obstructions and events with a fair amount of background noise thrown in. Until I get a good explanation of its purpose, I’ll just ignore it for now.

I think the FL ‘grouping’ is just positional apnoea that I’m working on (Soft Cervical Collar, more appropriate pillow(s), sleep position and possibly a bit more Pmin). 

I switched to ‘Dynamic’ mode and this significantly reduced RERAs and Central Hypopnea’s, but had little effect on the remaining Flow Limitations.

If my Prisma Smart Max had the SoftPAP 3 option, then I could probably resolve the remaining flow limitations more easily.

You mentioned in leono85’s therapy thread, upgrading of Prisma machines to support SoftPAP 3.  I had a quick look at the Lowenstein software update web pages, but couldn’t see any mention of recent firmware upgrades (latest is v3.15.3), or information on the possible addition of SoftPAP=3 to Prisma machines.  If you’ve got some further details on this, then it would be appreciated.  So for now my Prisma Smart Max still only goes up to 2 (Standard).

Lowenstein and Resmed seem to have very different underlying (and opaque) approaches to treatment, so direct comparisons of what each reports or presents in OSCAR can be difficult. 

Lowenstein in particular collects and presents a lot of additional data within OSCAR (and PrismaTS too).  Much of this seems more to do with their underlying PAP algorithms, than necessarily helping with titrating their machines.

All this information overload can lead you into a state of being part of the ‘unnecessarily worried well’.  At what point do you just cut your losses and say ‘that’s good enough’?

[Macka]

Regards the software upgrade, I have read that some Smart Max user have softpap3 so presumed it would be worth investigating. I know my Prisma20a has a firmware upgrade since last 6 months.

Even without softpap3 I think your flow trace looks quite good. You have some nice sections in there. I would say you needed to get your min pressure up higher and pull your max down to a tight range with softpap2 and dynamic mode on.

Change your flow limit flags to orange or yellow so they dont look as ominous! Give them the colour they deserve. Also switch off the epoch flagging. Your charts will look much better and you will be more relaxed yet focused on the important data.

[LoudSnorer]

Software / Operating System -  OSCAR version 1.5.1  macOS Sonoma 14.2.1 
....
I can provide Lowenstein SD Card Data if it helps with the above issue.  Just leave details of how and where to send it.
Thanks

Can you provide an archive (zip or 7z) of your sdcard.
Please include your username and device name.
Copy the archive to https://www.dropbox.com/request/H8ffFRuGtVmiUNWA2YbV

[WisNaeMe]

Just a quick not to say I have forwarded a zipped copy of my card data as requested.

Regards
WisNaeMe

[LoudSnorer]

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