CPAPtalk.com

VERY insightful post, ozij! Everything you said.

About this:

ozij wrote:It would be interesting to analyze the PSGs of people who dropped cpap - from other clinics -

Going back to a question I asked earlier in this thread, I still think it would be interesting to hear what Dr. Kracow usually prescribed for setting up the BiPAP Auto before he concluded this:

BarryKrakowMD wrote:Our clinical experience, however, with auto-bilevel by the Respironics device has been unsatisfactory. We have seen few patients who report a positive response to the device. To be fair though we only use the device with a patient who has already undergone 1 or more Bilevel titrations and failed to respond well at home. We then switch them to Bilevel, not to find new pressures, but rather to see whether an auto-bilevel device would provide them with a better clinical response. Less than one-third of these patients report dramatic improvement compared to fixed Bilevel pressures, so for these patients were delighted for their sake.

(excerpt from page 2 of this thread)

If almost one-third reported dramatic improvement with the BiPAP Auto, I think I'd call that pretty darn good, rather than "unsatisfactory." Especially considering that machine was being turned to only for a group who had already not responded well at home using plain bilevel machines.

I'd like to know if the prescribed min EPAP and max IPAP were 4 and 20 when the BiPAP Auto was ordered for those particular patients?

Was bi-flex turned on, or was a "rise" time adjusted? Was a setting for either of those on the prescription itself, or were those adjustments left to the discretion of the person setting up the machine for the patient?

If left to the "setter-upper", do you know if that person actually tried out each and every one of those two comfort settings with the patients before sending them home with the machine? Or were those features left at their default settings?

Was the max PS setting prescribed, or was that left to the "setter-upper?"

Of the two-thirds who still didn't do well at home, how many of those cited mask complaints as any part of the reason they couldn't "do" the treatment?

(Dr.) O. (PhD. in Psychology) wrote: I wonder what would happen if we had galvanic skin response data to accompany other PSG data.

I sure think that would be interesting as well, Ozij. I also resonate with your metaphor about that overarching bridge between mind and body.

SAG wrote:What?! Blaspheme! Of course it does!

Heheh! Life as a good-natured heretic is not easy, SAG. But I never said the physiologic mechanism or even the model should be discarded. I believe it to be a key piece to this puzzle. But I also believe it to be insufficient as an entire paradigm or explanation.

SAG wrote:I have a great graphic to help illustrate this, but "apparently" some people are offended by "graphics", which strikes me as quite ironic, since these same people appear to be so interested in "imagery".

I suspect Dr. Krakow's acceptable request has to do with his own cognitive style of problem solving. I'm familiar with the potentiation concept and I'm quite certain Dr. Krakow has been exposed to it long before coming here.

Would you be game for exploring possible merits that may be waiting on the other side of the bridge? It would be nice to try and plug in concepts and theories from both sides of the bridge. I suspect the full gamut of dysregulated central breathing cannot be understood by thinking inside or outside the analytic box. I have a hunch it may makes sense to freely flow inside and outside all sound theoretical boxes to build that overarching bridge.

-SWS wrote:Would you be game for exploring possible merits that may be waiting on the other side of the bridge? It would be nice to try and plug in concepts and theories from both sides of the bridge. I suspect the full gamut of dysregulated central breathing cannot be understood by thinking inside or outside the analytic box. I have a hunch it may makes sense to freely flow inside and outside all sound theoretical boxes to build that overarching bridge.

Sure, -SWS, I'm game for anything! But in re: CA origin:

Give me an apnea, any apnea, and I show you that the root of that apnea is in the loop.

OK, maybe Gus Portokalos helped me with that one.

Meanwhile, getting ready for the Game on Sunday. You know, almost all of the local teams are in the Super Bowl. I have my Giantriots (or is it Patriants?) hat to be on the safe side.

Go, whoever!!

SAG

I always assumed that loop gain was part of the equation, because it seemed to me that an anxious patient would hyperventilate off more CO2. In fact, on some diagnostic studies, where it's easier and cheaper to measure CO2, we do see relatively lower CO2 baselines in some patients who subsequently have trouble adapting to PAP therapy, and these patients do show more obvious anxiety at times.

My confusion has been that the CW is that bilevel should blow off more CO2 than CPAP and therefore, bilevel should make loop gain worse, which is counter to our experience of bilevel reducing central apneas in many of these anxious patients.

Do I think anxiety and loop gain are potentially two sides of the same coin? Unequivocally, yes. When I talk about anxiety, I never perceive it as a strictly "mind" thing; it always has a physiological component. So, mind-body is where I'm coming from, just as I think loop gain has a psychological component (see DF Klein's seminal work on CO2 and panic disorder).

I love graphics and imagery; but I would press my point that our discussions would be advanced further by a collaborative attempt to explain in words how the mind and body are interacting to induce centrals in CPAP patients and how bilevel seems to reduce them in some patients. I don't think anyone here disregards loop gain, but I don't see how a graphic is going to explain this mind-body connection until we know how to measure the mental and physical components we are interested in.

Rested gal, Regarding auto-bilevel, we never set it at 4 and 20, because everyone on this device has undergone a bilevel titration first at our sleep lab. Then we use the standard gap concept, I believe it's 7, and give the patient something close to the range we found on the titration, e.g. 6 to 13 and go from there. I'm not sure what other settings the DME uses, but I welcome your suggestions for fine-tuning adjustments and we'll consider those in future patients. Right now, we're trying a few patients on the RESMED auto-bilevel. Last, I'm not clear why you think one-third good results are impressive. As far as I can tell with early data from my center and other centers with whom I collaborate, the success rate on ASV appears to top 80%, and among these successful cases we often here phrases like, "that was the easiest PAP machine I've ever used" or "that was the best night of sleep I've had with a PAP machine."

Thanks, SAG. Theories are like refreshing thinking caps: the more to try on for size, the better!

Like Dr. K, Dr. O, and others, I am very interested in exploring possible relationships between mind/sleep as well as mind/SDB. I am curious to see if this statement:

Give me an apnea, any apnea, and I show you that the root of that apnea is in the loop.

Might better convert to something like this:

Give me an apnea, any apnea, and SAG, Gus, et al can show you that the apnea readily manifests in the loop, regardless of cause.

By now most of us are aware that Dr. Krakow uses a more aggressive BiLevel titration protocol than industry standard. Regardless Dr. Krakow attributes increased efficacy to rather aggressively normalizing the expiratory flow curve.
[on edit: several posts below I attempt to correct the above sentence by acknowledging that both E and I are aggressively "normalized" by Dr. Krakow's BiLevel titration protocol]

The review and debate so far is very understandable in my opinion. That's what practitioners of the scientific method do rather well. They also replicate and report their findings. I hope other researchers will consider the feasibility of doing just that. I think Dr. Krakow has done a novel job of making sure his body of theory and research does not get lost in the vast shuffle of medical literature.

For now I definitely want to continue hearing Dr. Krakow's viewpoints. But I definitely haven't discarded SAG's viewpoints. I'm hoping to see pieces of wisdom fit wherever they can and should be fit.

Thanks to Dr. Krakow and all posters in this thread!

Oh, all right. I'll cut down on the graphics. It won't be easy, tho. Maybe I can post some "Tables" instead. That should help with "Graphics Withdrawal".

Which seminal (I'd like to see what root Gus thought that word came from) article are you referring to - this one?

False suffocation alarms, spontaneous panics, and related conditions. An integrative hypothesis, D. F. Klein, Arch Gen Psychiatry. 1993;50:306-317

Doesn't appear to be online, I'll have to go over to the ol' biblioteca and see if it's there. At first glimpse, a lot of that stuff is measured during Wake, and physiologically, the difference between Wake and Sleep is like Night and Day, so...

LOL! SAG made a funny!

Anyway, I'll try to find some panicky people and see what ETCO2 did during sleep.

SAG

BTW, when you say

BarryKrakowMD wrote:Right now, we're trying a few patients on the RESMED auto-bilevel.

which machine are you referring to? AdaptSV, Malibu or the new VPAPAuto? VPAP Auto is soooo quiet, you really have to factor in the noise level as well.

SAG

BarryKrakowMD wrote:Rested gal, Regarding auto-bilevel, we never set it at 4 and 20, because everyone on this device has undergone a bilevel titration first at our sleep lab. Then we use the standard gap concept, I believe it's 7, and give the patient something close to the range we found on the titration, e.g. 6 to 13 and go from there.

I'm glad to hear that. Sounds like a good way to start their EPAP/IPAP and PS (the "gap") settings on the BiPAP Auto with Bi-flex.

In your example, the machine would start out each night using EPAP 6, IPAP 8. The machine would do its thing from there -- varying those pressures supposedly "as needed."

Personally, I'd let no more than 5 nights go by before doing a download to look at the Daily Details graphs (not the Summary or Trend data) to see if EPAP was actually staying down at 6 most of the time and whether the person was bumping the IPAP ceiling at all. If I saw that EPAP had to go up very often and/or that the machine was hitting the IPAP max at all, I'd raise those pressure settings accordingly.

I especially like to look at the individual nights' "Daily Details" graphs to see what the leak line is doing. I'd want to see that very early (within the first five days) because if significant leaks from mask or mouth are showing up on the data, that needs to be addressed as soon as possible. Massive leaks, even if they don't reach "Large Leak" (LL) levels, can play havoc with how the machine decides what pressure to use.

Seven for "the gap"...the PS setting, or Max Press Sup (Maximum Pressure Support) as it's called in the M series BiPAP Auto ... sounds good. The most that can be set for is 8 . Of course the PS can't be set for more than the difference between min EPAP/max IPAP, which in that example was PS 7 (13 minus 6 = 7 . ) Unless there's a medical reason that an individual person should have a closer gap, I think it is good to have the PS set for as much as it will allow (given the particular EPAP/IPAP settings) in order to let EPAP and IPAP do their own thing as independently of each other as possible.

All that said, well... I'm not a doctor, of course. Those are just my layperson's opinion about using the BiPAP Auto -- knowing nothing at all about any health issues the individual user might have that would suggest using different settings. A smaller "gap" for PS, for example.

BarryKrakowMD wrote: I'm not sure what other settings the DME uses, but I welcome your suggestions for fine-tuning adjustments and we'll consider those in future patients. Right now, we're trying a few patients on the RESMED auto-bilevel. Last, I'm not clear why you think one-third good results are impressive. As far as I can tell with early data from my center and other centers with whom I collaborate, the success rate on ASV appears to top 80%, and among these successful cases we often here phrases like, "that was the easiest PAP machine I've ever used" or "that was the best night of sleep I've had with a PAP machine."

Well, I'm not sure where an Adaptive Servo Ventilator machine entered the picture when I thought we were originally talking about repeat failures with traditional bilevel being switched to the BiPAP Auto with Bi-flex -- which is not an ASV type of machine. Unless you were using the BiPAP Auto SV instead of the BiPAP Auto with Bi-flex?

Anyway, if regular bilevel is an apple, and BiPAP Auto with Bi-flex is an orange, then I'd say bringing an ASV machine into the comparison mix is like rolling in a grapefruit now.

So, yes...between just the two types of machines I thought we were discussing -- traditional bilevel and the BiPAP Auto with Bi-flex -- I'd say that to see "dramatic improvement" in almost one-third of the people in a hard core group of failed bilevel users who are switched to BiPAP Auto is impressive.

If a completely different type of machine -- one that utilizes Adaptive Servo Ventilation -- helps even more of them... by all means, yes, go for what works for them! Some of the additional "improvers" might very well be CSDB cases.

Back to the BiPAP Auto with Bi-flex:

BarryKrakowMD wrote:I'm not sure what other settings the DME uses, but I welcome your suggestions for fine-tuning adjustments and we'll consider those in future patients.

Well, first and foremost I'd suggest downloading the Smart Card during the first five days -- and choosing "Full Details" to look at when viewing the report. I wouldn't even bother to look at the Summary or Trend data, or even the first three pages of the "Full Details" report. Beginning on page 4 of the Full Details report, look closely at the Daily Details graph for what the EPAP and IPAP are hitting, as well as what the leak rate is doing. Don't look at the overall averages...actually look at the each individual night's data on those five "Daily Details" graphs.

As for initial settings beyond EPAP/IPAP and Max Press Sup, I think it is extremely important for the DME to try out each "comfort" setting (there will be 8 settings to try, including two "off's") for Bi-flex and for "Rise Comfort." Both cannot be used at the same time. It's either/or, and both can be "off" if using neither suits best. Trying them can be done right in the DME's office or with the DME visiting the home.

Would take probably 15 minutes or less to go through all of them, as that is best done with the user awake and trying each setting for a few breaths. The person doesn't even have to be laying down. The user will know within a few breaths if a feature/setting feels "smooth" or feels abrupt or "not as good" as the previous setting. Personally, Bi-flex at a setting of 3 feels best to me, but setting a rise time instead of setting any bi-flex level could feel better to the very next person.

My guess is that most DMEs setting up the BiPAP Auto with Bi-flex simply leave the "comfort" settings at their defaults. Or at most might set bi-flex at what the DME was accustomed to setting it -- probably at 2. I doubt that many of them would think it necessary to spend the few extra minutes it would take to get the user's feedback while methodically trying each bi-flex and each "rise comfort" setting.

I'd also remind the DME to be sure the PS (Max Press Sup) setting is set for as much as it will allow (8 being as high as it can be set) after they finish setting the EPAP/IPAP. Because PS will get moved down if, while running through the EPAP/IPAP numbers during the setup, the difference between EPAP/IPAP gets lessened, even temporarily, before the final EPAP/IPAP is chosen. But the PS setting will not go UP automatically when the eventual wider EPAP/IPAP is set. The DME needs to take a last look at the PS and punch that button repeatedly to be sure it's set for the max it will allow. Unless, of course, the prescription calls for a specific PS gap for that person.

Dr. Krakow,
Have you noticed (in the lab) how dramatically the pressures
needed to achieve good sleep, drop with the introduction of a
nice dental appliance like the TAP 3? Do you give your patients
the opportunity to explore this possibility?

BarryKrakowMD wrote:Do I think anxiety and loop gain are potentially two sides of the same coin? Unequivocally, yes. When I talk about anxiety, I never perceive it as a strictly "mind" thing; it always has a physiological component. So, mind-body is where I'm coming from, just as I think loop gain has a psychological component (see DF Klein's seminal work on CO2 and panic disorder).

OK, I'm done!

The CO2 mechanism described only applies to wake.

The only elicited response is hyperventilation.

The study says essentially that if you put a plastic bag over the head of a patient with panic disorder they get more panicky.

This can easily be demonstrated in anybody.

Lowe et al could not make the jump from idiopathic hyperventilation to CSA.

Trying to relate this to sleep and CA will be difficult to impossible since persistent CA often responds to increased levels of ICO2 (don't get frequie, tho).

If you do find somebody like this tho, give 'em some Paxil and /or Ativan.

Whoa, the Huskies are on a roll.
SAG

Talk about coincidence... this, from another thread:

kurtr wrote:I have been given a demo Respironics Bipap Pro 2 to use by my DME while a newer bipap model comes in. I have been using a Resmed S8 in Auto mode for years.
I have not slept with it yet just tried it while relaxing to get used to it. My question is it cuts out on the pressure about 3/4 into my in breath and goes into the lower level like it is not in sync at all with my breathing.
This is the first time I have tried a Bipap. Is there something wrong?

Thanks,
Kurt

viewtopic/t28109/Demo-Bipap-question.html

That kind of thing happening (and I've read of that particular problem a LOT on the message board) is why I think doctors should be sure to instruct the DMEs to spend that little bit of extra time having the user try out all 8 (if you include two "off"'s) settings for bi-flex and rise time. Or for whatever "comfort" settings any other brand of bilevel machine has.

OK, there's a few things that are still outstanding. One was the 120-second data window of our PB420E patient. There's a big ol' obstructive apnea in there that's continuous (I know it don't look that way, but it is, trust me):



Ain't found it yet?



There's a bunch of stuff to be learned here. First, if you look at one channel and think you see something (like "bumps"), you can look at other channels to support (or detract from) your analysis. In the case of obstructive events, abdominal and thoracic effort belt activity can be extremely valuable in determining whether or not there is obstruction. During normal breathing, they will move in unision (or darn close to it). As obstruction occurs, the chest will begin to drag behind, until the obstruction causes the chest to cave in during inspiration, and paradoxical breathing occurs (the waveforms become a mirror image of each other). This is the perfect example of as bad as it gets, but the whole transition from unobstructed breathing > flow limitation > obstructive hypopnea > obstructive apnea can be tracked through effort belts, which is why looking at the whole picture is essential to proper analysis, and why a snippet of breathing tells little of the story.

The other thing is those huge blips in the Patient Effort (arrow). You may have already figured out that they aren't anything the patient did, they represent the pressure change the PB420E sent in trying to overcome the obstructive apnea (noted in the Pressure Channel). Right, 1.0 cmH2O pressure changes. So, knowing now that the Patient Flow channel is monitoring about a 1.0 cmH2O pressure scale, is the possibility of machine artifact back on the table? Clearly, knowing how the waveform was set up is critical in trying to figure out what's happening. Further, the original waveform:



in all liklihood has been specifically set up to filter out the very thing that it is claimed to be identifying, namely, flutter.

SAG

SAG wrote:There's a bunch of stuff to be learned here.... Ain't found it yet?

SAG wrote:... First, if you look at one channel and think you see something (like "bumps"), you can look at other channels to support (or detract from) your analysis.

SAG wrote:looking at the whole picture is essential to proper analysis, and why a snippet of breathing tells little of the story.

Limited data scope has been a recurring theme on this message board. Multiple channels are clearly better than one, and a complete data set of epochs is clearly preferable as well. The same basic theme of limited data-scope has been used in the past to point out the inherent weaknesses in single-channel APAP machines. I won't counter by saying that APAP sleep-event measurement can be as accurate as PSG measurement. It simply cannot be IMO.

But I will counter by saying that the APAP algorithm and PSG session perform completely different analytic methods on that flow channel. Out of algorithmic necessity, the APAP channel will derive multiple input signals that are not derived from the same flow channel during a PSG.

And toward the end of demonstrating precisely what/why/how an APAP misses what it does, human-eye analysis is unintentionally misleading IMO. The APAP does track multiple input signals. More importantly, the APAP necessarily works with temporal variables. The APAP algorithm does not at all have the time-domain micro-snippet limitations imposed by these demonstrations. And most importantly, any APAP algorithm is guaranteed to employ much more robust analytic methods than will ever be performed by a cursory inspection of human eyes.

Human eyes cannot perform algorithmic-equivalent exercises on PSG waveform analysis either---especially as depth-of-data analysis becomes increasingly important (such as in the domain of quantitative temporal analysis). To demonstrate the depth-of-analysis shortcoming of the human mind, think of how many sleep professionals (SAG included) were surprised by the CSDB/CompSA prevalence rate unveiled by the Mayo group and yet other research teams. The cyclic-alternating-pattern waveform manifestation (CAP) very nicely demonstrates that same human-mind depth-of-analysis flaw that has been overcome by incredibly robust computational methods as well.

So please think twice, kind sir, before displaying unintentionally misleading micro-snippets of information for cursory inspection to demonstrate the shortcomings of robust computational methods--or of the analysis of other researchers for that matter.

SAG wrote:looking at the whole picture is essential to proper analysis, and why a snippet of breathing tells little of the story.

Human cognition and its end-result variation (regarding brain-based pattern recognition) is precisely the reason that when a characteristically novel researcher places a pattern of bumps on our screens, and then earnestly conveys why he believes he has encountered an efficacy pattern, that I am very interested in hearing what he has to say.

I suspect that right now many of us are much less interested in having Dr. Krakow's theories and analysis displaced with alternatives (that are always readily available for comparison later), and that many of us are much more interested in hearing the complete novel analysis.

I personally think it's preferable to maintain differences of opinion as we listen to others. But if we truly want to glean the experiences of others, then we have to preserve the flow and continuity of the very discussion venue on which they rely. Regarding differences of opinion: If any one researcher happened to be twice as smart as Albert Einstein and Albert Schweitzer combined (2xAlbert-squared), then we should also expect to find errors and inconsistencies in their work--especially if it's a work in progress.

I know SAG feels comfortable displaying loop-gain theory and waveform analysis. And for that I am profusely grateful! But I hope that Dr. Krakow continues feeling comfortable expressing his views. And I express my extreme gratitude for the information he has so kindly shared with us already.


disclaimer: all of them.

Very well said, -SWS.

I join both the thanks for what Dr. Krakow has shared, and the hopes he will continue to do so.

O.

SWS I hope that Dr. Krakow continues feeling comfortable expressing his views. And I express my extreme gratitude for the information he has so kindly shared with us already.

Thank you SWS for the insights into the interpretation of those "graphics." It gets difficult to sort out the information when it gets highly technical I certainly hope Dr. Krakow continues to contribute many more BiPAP Pearls. I'm not ready to start another education to learn all I'd need to understand some of the recent threads. I have begun to wonder if I somehow stumbled into a Binary forum. I appreciate and want to have those knowledgeable people doing my sleep studies-then I want to have someone who can translate the results into something I can use. I appreciate Dr. Krakow's ability to explain the complex. I hope he is just off presenting at a conference.
Will be starting BiPAP soon thanks to reading his posts and realizing I could/should be getting more out of PAP treatment.