Why doesn't APAP respond to apneas?

[ozij]

I think Bev's EDS may be caused by those consant little pressure challenges from the Respironic, or by the Lexapro or both.

O.

FYI: She is NO longer on Lexapro, that has been mentioned several times now.

FYI: Bev was taking Lexapro and melatonin for almost a whole year of her therapy.
O.

[rested gal]

We tend to talk about you at times like you're not even here, don't we?

I need to work on that. I envision that we're all huddled together in supportive analysis and conversation---happily putting our heads together trying to help Bev. So the whole exercise is all about Bev and all for Bev in my view. But some of that conversation will go back and forth in response to specific comments.

Oh...no, no, nooooo...I didn't mean that as any kind of chide at all!!!! Not at all! So sorry if that came across awkwardly! I was just laughing as I thought about how Bev's reading, reading, reading, while we're busily posting "about" her. It absolutely IS all of us showing support of Bev...everything in this thread....from posting charts to speculating about what might be happening.

Or like snoredog put it (that was cute!)

Poor Bev, this is like MASH, she's laying there trying to get some sleep and we all walk by and grab her chart, she must think her cot is next to the chow line

[dsm]

Snoredog,

You raised the issue in a post 2 days back about the SV calculating Bev's INSP time (BPM=AUTO). I was responding late at night & not able to explore this line fully.
Your point was to do with how the SV might be calculating INSP and the effect this could be having on Bev - IIRC you also said you understood the SV doesn't add PS when in backup mode. We also discussed Bev breathing fast & I pointed out her max BPM didn't exceed 17BPM.

I mentioned I had chosen to do my test using BPM=10 as to evaluate what happens when BPM=AUTO would require me to do it as the live subject & I would need to perfect a way to hold my breath for long periods without inducing leaks or turning blue

Do you want to explore this a bit more as it is an interesting line. If yes can you restate the line of thinking again (am assuming we have even more info that may qualify your thoughts)

DSM

[-SWS]

I don't understand why you consider the titration charts more meaningful that her results when sleeping at home on APAP.

Well, we're even. Because I don't understand why you even think that I think that way. I never assigned any sort of relational importance to those charts relative to all the other potentially salient clues. I don't understand why anyone would dismiss a fairly atypical and pressure unresolved pattern of breathing disruption during two PSGs, however.

How do you explain the fact that Bev's AHI is lower when she raises the auto pressure?

When she raises her Auto pressure to that 14-17 cm range, her APAP treatment probably closely approaches what happened in the lab at CPAP=14 cm: 14 cm = 4.7 AHI (@12.9 min).

The good news is that's about her best AHI in the lab as well as at home with APAP made to work almost like CPAP@14 cm. The bad news is that's also nearly tied for Bev's worst RDI at 60. If her RDI home results with APAP artificially stuck at 14 cm are anything like her PSG results with CPAP also stuck at 14 cm, it's no wonder she suffers poor daytime cognition and EDS. Her results up and down both PSG pressure charts show either unacceptable AHI, RDI, or both.

What does it mean, that the APAP machine can and does reduce her AHI to less than 5? Is that - at all - possible in cases of CompSA/CSDB? It was my impression that CompSA/CSDB is diagnosed based on the response to treatment, not to titration.

As if CompSA/CSDB diagnostic criteria was somehow fully or even adequately developed?

I'm admittedly surprised to hear you embrace that semi-developed CSDB/CompSA criteria related to AHI. I thought you personally noticed that you feel noticeably worse when your AHI gets above only three. So much for well-established standard apnea diagnostic criteria, let alone undeveloped CompSA/CSDB diagnostic criteria relative to AHI (a highly debatable benchmark in itself---especially in relation to virtually unknown CSDB/CompSA).

So what mechanism makes you feel so poorly when your own "vanilla" AHI dips just above that three mark? And what mechanism makes Bev feel poorly when her 14-17 cm APAP machine measures an AHI below 5? I think we both acknowledge that AHI thresholds vary regarding noticeable pathology---and they don't always match up with diagnostic criteria either. At least in Bev's case we know that she can use CPAP at 14, but still end up with a mysterious RDI of 60 while also enjoying an AHI below 5.

If normal breathing can be dysregulated by machines, then how can the Bev's dysregulation on the SV prove anything?

It doesn't prove anything all by itself. Well, actually I think it proves that more investigation in the lab is warranted. After all, not everyone dysregulates so easily on machines. Not everyone turns in two highly atypical "pressure unresolved" PSGs. Not everyone has such hard and wild apnea spikes with non-LL leaks. Not everyone complains of poor daytime cognition, EDS, and even PAP related biologic discomfort.

Now that I think about it some more, I still think Bev's a great candidate for CompSA/CSDB. And I still doubt that moderate pressure bumps here and there can resolve her challenging pathophsyiology.

[-SWS]

I think Bev's EDS may be caused by those consant little pressure challenges from the Respironic, or by the Lexapro or both.

We've seen that in the PSG Bev can centrally dysregulate on BiLevel but not on CPAP.

Various pressure-based sensory stimuli is conceivably at the root of Bev's poor sleep. So the big question is how might Bev sleep at home on CPAP=14 (thus we're taking away all those pressure chairs). Be curious to see those home based results both with and without C-Flex. And more importantly, to hear whether Bev notices any improvement the following day by taking those pressure chairs completely away via CPAP @ 14 cm.

[ozij]

One of those targeted phenotypes is complex sleep apnea (CompSA/CSDB), which Bev shows some indicators for. One indicator of CompSA/CSDB is the inability of the clinician to reduce sustained AHI below 5 with CPAP. Let's review Bev's CPAP titration:

What does it mean, that the APAP machine can and does reduce her AHI to less than 5? Is that - at all - possible in cases of CompSA/CSDB? It was my impression that CompSA/CSDB is diagnosed based on the response to treatment, not to titration.

As if CompSA/CSDB diagnostic criteria was somehow fully or even adequately developed?

Bev's treatment AHI is 1.4 or so.

If normal breathing can be dysregulated by machines, then how can the Bev's dysregulation on the SV prove anything?

It doesn't prove anything all by itself. Well, actually I think it proves that more investigation in the lab is warranted.

Agreed.

And what mechanism makes Bev feel poorly when her 14-17 cm APAP machine measures an AHI below 5?

Lexapro and pressure variations (OK, I see you've just responded to that in you next post, as I'm writing.

I don't understand why anyone would dismiss a fairly atypical and pressure unresolved pattern of breathing disruption during a PSG.

Because Bev said the mask bothered her so badly, and because the PSGs are 2 nights worth of data, and Bev has been consistetnly acheiving low AHIs that were not achieved during the PSG.

I guess you're saying CompSA/CSDB may be defined by an existence of RDI. I have no argument with that.

O.

[ozij]

I think Bev's EDS may be caused by those consant little pressure challenges from the Respironic, or by the Lexapro or both.

We've seen that in the PSG Bev can centrally dysregulate on BiLevel but not on CPAP.

Various pressure-based sensory stimuli is conceivably at the root of Bev's poor sleep. So the big question is how might Bev sleep at home on CPAP=14 (thus we're taking away all those pressure chairs). Be curious to see those home based results both with and without C-Flex. And more importantly, to hear whether Bev notices any improvement the following day by taking those pressure chairs completely away via CPAP @ 14 cm.

Or having obstructive apneas at 14....

OK guys, it way past my bedtime here - I'll see what you all come up with tomorrow.

O.

[-SWS]

One of those targeted phenotypes is complex sleep apnea (CompSA/CSDB), which Bev shows some indicators for. One indicator of CompSA/CSDB is the inability of the clinician to reduce sustained AHI below 5 with CPAP. Let's review Bev's CPAP titration:

What does it mean, that the APAP machine can and does reduce her AHI to less than 5? Is that - at all - possible in cases of CompSA/CSDB? It was my impression that CompSA/CSDB is diagnosed based on the response to treatment, not to titration.

As if CompSA/CSDB diagnostic criteria was somehow fully or even adequately developed?

Bev's treatment AHI is 1.4 or so.

Bev having found a pressure that yields an AHI of 1.4 doesn't come close to shoeing her in with vanilla OSA. Below a CompSA/CSDB treatment AHI is discussed that's great yet is also a treatment failure for also having left too many residual RERA's:

Initially, we were hesitant to increase the EEP too rapidly; with experience, we have become more aggressive with our titrations...In another patient, undertitration occurred as the technologist adjusted the EEP for apneas and hypopneas, but did not adequately increase the pressure for residual RERAs. Our experience suggests that some of the early failures with ASV may be inadequate SDC/technologist experience, and not necessarily a problem with the device.

And I've never seen any medical literature that even hints measured CompSA/CSDB treatment response should be pressure-linear. I've seen non-linear pressure results and I've even seen the obstructive component of CompSA/CSDB elevate in a non-linear pressure distribution as well. It's entirely conceivable that a non-linear CompSA/CSDB pressure response can yield a low AHI for Bev at 14----but also leave an unacceptable RERA component. I'd even expect it to occur somewhere across a vast CompSA/CSDB patient population.

And what mechanism makes Bev feel poorly when her 14-17 cm APAP machine measures an AHI below 5?

Lexapro and pressure variations (OK, I see you've just responded to that in you next post, as I'm writing.)

Actually I had repeatedly mentioned pressure variations throughout this thread as a potential stimulus/response issue for Bev. Lexapro hasn't been
potentially skewing Bev's 14-17 cm results since she discontinued that a while back.

I guess you're saying CompSA/CSDB may be defined by an existence of RDI. I have no argument with that.

It may come down to that. The researchers fully admit they're trying to get a handle on what it is and how to measure it. But I mainly suspect that Bev has managed to settle into a non-linear CompSA/CSDB pressure point that doesn't exacerbate her AHI so much, but leaves biologically devastating RERA's, as with the failed case study I have cited above.

But on the note of those outstanding and devastating RERA's related to CompSA/CSDB that are not fully resolved. There may be some parasympathetic airway narrowing going on there as well. And there may be wild disturbance related C.A.P. patterns going on there. They are not A. They are not H. They are not even suspected to be ordinary passive FL. And yet they are supposedly devastating to sleep architecture, daytime cognition, and EDS. And you want to know what? They just may score as FL or marginal/intermediate FL.

Or having obstructive apneas at 14....

...or undifferentiated centrals ... or neither ...or both. Methodical trial and error really is performed much better in the sleep lab IMO. But methodical trial and error at home has proven far better than none at all when people here feel poorly in spite of or even because of poor treatment. That latter happens here again and again because sleep doctors lend a deaf ear to devastating daytime symptoms.

OK guys, it way past my bedtime here - I'll see what you all come up with tomorrow.

Night night.

[Snoredog]

The good news is that's about her best AHI in the lab as well as at home with APAP made to work almost like CPAP@14 cm. The bad news is that's also nearly tied for Bev's worst RDI at 60. If her RDI home results with APAP artificially stuck at 14 cm are anything like her PSG results with CPAP also stuck at 14 cm, it's no wonder she suffers poor daytime cognition and EDS. Her results up and down both PSG pressure charts show either unacceptable AHI, RDI, or both.

I couldn't agree more, it is why we are chasing this, get AHI down, RDI is up. Is there spontaneous arousals contributing to EDS? We don't know, if we can get her PS up with SV without causing a train wreck the hope is she gets better sleep.

Maybe we need only 4 cm or 6 cm fixed pressure support? Maybe we need BPM=Off. Ideally a lab titration would answer those questions, but I imagine it will be at least January for her new insurance year to begin before she can have another study done. Then if she has a high deductible that is going to cost her more. If you have the machine and the reports, might as well try, until we can get her sleeping better this is probably going to be a Fri=Sat night trial.

SWS: Out of all those lab studies, what settings do you see offering her more REM? Problem with those titrations is they didn't use much Pressure Support, I wonder why that was?

[Snoredog]

Snoredog,

You raised the issue in a post 2 days back about the SV calculating Bev's INSP time (BPM=AUTO). I was responding late at night & not able to explore this line fully.
Your point was to do with how the SV might be calculating INSP and the effect this could be having on Bev - IIRC you also said you understood the SV doesn't add PS when in backup mode. We also discussed Bev breathing fast & I pointed out her max BPM didn't exceed 17BPM.

I mentioned I had chosen to do my test using BPM=10 as to evaluate what happens when BPM=AUTO would require me to do it as the live subject & I would need to perfect a way to hold my breath for long periods without inducing leaks or turning blue

Do you want to explore this a bit more as it is an interesting line. If yes can you restate the line of thinking again (am assuming we have even more info that may qualify your thoughts)

DSM

We have a different wave of thinking about this machine. My understanding is Backup Mode or BPM is fixed (when not BPM=Auto), meaning it is just like any other Bipap with a backup mode. When you set BPM=10 for example, it puts that backup mode in fixed mode. So if you set it to BPM=10, you also have to set Inspiration Timer (i.e. Ti) and Rise Time. Now in your video test I think you tired to demonstrate this. Okay, now lets say you set BPM=10, so 60 seconds (1 min/10=6 secs per breath), if a 1.2 sec inspiration time is used that leaves 4.8 seconds for exhale. Now I believe you had set IPAP Max to 25 cm? and EPAP=10?

So on your gage, we should have seen:

EPAP/Minimum pressure =10 cm (we seen that)
IPAP/Min=was at or close to 10 cm (we seen that)
IPAP "working" would move from 10 to 25 cm (we seen that),
but,
if IT timer was 1 second we should have seen it take 1 second for the needle to move up from 10 cm to 25 cm. If it was 2 seconds, 2 seconds, if it was 3 seconds. In other words the higher the IT timer the longer it should have taken to go from 10 to 25.
now,
IF IT timer was shorter, would it stop at the end of the timer before it got to the IPAP Max? Example, if IT was 1.0 would it stop at say 20 cm? We don't know.
If the machine is in fully SV or Auto mode, how does it determine IT time? digital autotrak?
lastly,
If the SV and backup mode is Auto and it uses the "patients" last 4 minutes to determine peak and tidal volumes, does the auto algorithm automatically do the math to lower BPM and set IT and Rise Time? (I'm pretty sure it uses digital autotrack for Rise Time but not sure on the others.

The point to all this is, let's say Bev is breathing really fast maybe 18 BPM and machine finds that and for BPM=AUTO and follows its own protocol of spontaneous BPM -2, that means in backup mode it will set BPM=16, that could still be way too fast for her. I haven't seen a place where you can input the patient's height to know what target volumes should be. Since the range of tidal volume can be from 440ml to 660ml how does it know what is best for Bev?

Your test was very interesting, were you able to observe the LCD and see when the machine was in SV mode vs backup?
Yes, I am still interested in finding out how it finds the ideal IT time.

Note: you can use a 4mm hole to simulate typical mask leak rate so you don't have to turn blue, that is what my manometer has.

[OutaSync]

I am very moved and feel honored that you are all spending so much time trying to help me out. I'm still unclear as to what settings I should try next. I'm hesitant to do much experimenting during the work week, as I have to be able to function during the day. This past weekend, I was so tired that I never even got dressed. For the last two nights I have been using my APAP, with the usual low AHI and lots of chairs across the top. I can do straight CPAP @14 without any flex tonight and see how that goes. That's to see if it's the pressure changes that are disturbing my sleep?

BTW, I'm going over to the sleep center to pick up my discs tomorrow morning. Does anyone still want to see them? I hope it doesn't include the video of me. I didn't know they had a camera up there when I was changing.

Bev

[OutaSync]

I just pulled up my report from last night. It looks beautiful, doesn't it? You would think I should be well rested.




Bev

[-SWS]

SWS: Out of all those lab studies, what settings do you see offering her more REM? Problem with those titrations is they didn't use much Pressure Support, I wonder why that was?

Snoredog, when I look up and down those pressure charts I get the same impression I do when I get to the farmer's market on the last hour of the last day: not a lot of great choices. Arguably none.

We might attribute Lexapro to some of that effect, but probably not that non-linear AHI/pressure relationship on both charts that just doesn't look very "vanilla OSA" to me. My impression looking at both pressure charts is that person will likely not sleep great with ordinary BiLevel or CPAP. I also don't think most patients will have that many sleep disturbance problems because of Lexapro. If we attribute all that EDS and poor daytime cognition to Lexapro, what do we do long after the Lexapro is discontinued and drastic daytime symptoms are still there? I'm personally disinclined to suspect Lexapro is to blame for as much of that havoc on those sleep charts as we see---in light of no recent apparent changes in symptoms.

Long story short: I'd shop for a different farmer's market where the yield may be better. Different machine and/or different lab.

I am very moved and feel honored that you are all spending so much time trying to help me out.

Everyone wants to get this figured out, Bev.

I'm still unclear as to what settings I should try next. I'm hesitant to do much experimenting during the work week, as I have to be able to function during the day.

I agree with that strategy wholeheartedly: rest up with the 14-17 APAP range until you feel back to your recent "best".

BTW, I'm going over to the sleep center to pick up my discs tomorrow morning. Does anyone still want to see them?

Bev, I think you lucked out in this category. SAG, our inordinately sharp sleep pro, has agreed to have a look at these. Hey, that's as good as winning a contest in my book! I respect his PSG skills immensely.

We would also like to follow along---at least I would! Would you mind PM'ing SAG to proceed with the files on those discs?

[Snoredog]

I wanna wait and see what SAG says.

SWS: see Bev's latest Encore report, notice how the little chairs change when an event is detected, notice her AHI even went down further to .8 (Bev you can stop trying to lower your AHI now )

[dsm]

Snoredog,

You raised the issue in a post 2 days back about the SV calculating Bev's INSP time (BPM=AUTO). I was responding late at night & not able to explore this line fully.
Your point was to do with how the SV might be calculating INSP and the effect this could be having on Bev - IIRC you also said you understood the SV doesn't add PS when in backup mode. We also discussed Bev breathing fast & I pointed out her max BPM didn't exceed 17BPM.

I mentioned I had chosen to do my test using BPM=10 as to evaluate what happens when BPM=AUTO would require me to do it as the live subject & I would need to perfect a way to hold my breath for long periods without inducing leaks or turning blue

Do you want to explore this a bit more as it is an interesting line. If yes can you restate the line of thinking again (am assuming we have even more info that may qualify your thoughts)

DSM

We have a different wave of thinking about this machine. My understanding is Backup Mode or BPM is fixed (when not BPM=Auto), meaning it is just like any other Bipap with a backup mode Where the SV differs is that if PS is activated (IpapMax > IpapMin, then the backup cycling when it is activated will add 2CMs every failed epap-ipap cycle - my video shows this in action. BPM=10 IT=1.7 (I can change the 1.7 to 1.2 & try again) - said another way when ipap fails to trigger a breath (assuming we say 100ml is the minimum) PS will be invoked (by bumping ipapCurr by 2 CMs) if PS has been set and IpapMax has not been reached . When you set BPM=10 for example, it puts that backup mode in fixed mode. So if you set it to BPM=10, you also have to set Inspiration Timer (i.e. Ti) and Rise Time. Now in your video test I think you tired to demonstrate this. Okay, now lets say you set BPM=10, so 60 seconds (1 min/10=6 secs per breath), if a 1.2 sec inspiration time is used that leaves 4.8 seconds for exhale. Now I believe you had set IPAP Max to 25 cm? IpapMax was set to 30 but only went aaprox 10 above IpapMin (on ipap phase it hovered around 22-23) and EPAP=10?

So on your gage, we should have seen:

EPAP/Minimum pressure =10 cm (we seen that)
IPAP/Min=was at or close to 10 cm (we seen that)
IPAP "working" would move from 10 to 25 cm (we seen that), Actually it varied between 21-24 - I may try this test again
but,
if IT timer was 1 second we should have seen it take 1 second for the needle to move up from 10 cm to 25 cm. If it was 2 seconds, 2 seconds, if it was 3 seconds. In other words the higher the IT timer the longer it should have taken to go from 10 to 25.
now,
IF IT timer was shorter, would it stop at the end of the timer before it got to the IPAP Max? Example, if IT was 1.0 would it stop at say 20 cm? We don't know.
If the machine is in fully SV or Auto mode, how does it determine IT time? digital autotrak? I think autotrak does handle it
lastly,
If the SV and backup mode is Auto and it uses the "patients" last 4 minutes to determine peak and tidal volumes, does the auto algorithm automatically do the math to lower BPM and set IT and Rise Time? Lets do a scenario, sleeper is tracking av peak flow & av rate then starts to slow their breathing rate below the accepted target, the SV I believe, will use cycling to try to speed up the sleeper's rate to get back on target - I believe it uses PS boost as well to achieve this when trying to speed the sleepers rate up (boost of +2 CMs per breath) - if on the other hand the sleeper starts to drop below av peak flow but rate is the same, the machine activates PS boost each inhale until back at the target flow - 3rd situation is if the sleeper starts breathing too fast, the SV will start to cycle at the slower rate & I believe it drops PS activity (reverts to IpapMin) (I'm pretty sure it uses digital autotrack for Rise Time but not sure on the others.

The point to all this is, let's say Bev is breathing really fast maybe 18 BPM and machine finds that am assuming you are meaning the sleepers BPM rate has gone over the tracked target rate and for BPM=AUTO and follows its own protocol of spontaneous BPM -2, that means in backup mode it will set BPM=16, that could still be way too fast for her But if SV was tracker her average as 16 then it would try to keep her to that tracking . In BPM=AUTO mode, say the machine is tracking Bev at BPM av of 13.5 & she goes to 15.5 - that is 2 over her 4-min window average, if 2 is the threshold (I don't actually knw what it uses) then the machine will say, sleeper is breathing too fast I will cycle at 15.5 to try to slow the rate I haven't seen a place where you can input the patient's height to know what target volumes should be. Since the range of tidal volume can be from 440ml to 660ml how does it know what is best for Bev? Setting a volume is what the AVAPS machine does, the SV really tries to hold the sleeper to within an average BPM rate band (which I don't know the numbers for and will try to maintain an average peak flow target for each breath - I assume the numbers allow the sleeper some latitude in tidal flow & BPM speed as these will vary slowly through the night. Bev's flow & rate vary far to quickly & erratically & the machine will be trying to do a lot of correcting

Your test was very interesting, were you able to observe the LCD and see when the machine was in SV mode vs backup? I did look at the LCD but when I did the filming was having a hard time keeping the camera focus. - may try some other tests this w/e
Yes, I am still interested in finding out how it finds the ideal IT time. I'll also play with the INSP value - vary from 1.2 to 2 & see what that does

Note: you can use a 4mm hole to simulate typical mask leak rate so you don't have to turn blue, that is what my manometer has.