PurSleep gone for now & why I did what I did

[GuestForADay]

OMG, OMG – PLEASE DON’T let it be over!
It’s better than GWTW!

The only thing left to do … would be to cast the movie version:

Working Title: One Flew Over the Sleep Apneas’ Nest

Starring:
SG …………………………….Russell Crowe
CQ ……………………………Cate Blanchett

In alphabetical order:
blarg………………………….George Clooney
Daniel ………………………Liam Neeson
(from sleepapnea.org)
drb…………………………….John Malkovich
dsm……………………………Robin Williams
FDA agent ……………… Kevin Costner
MrMango……………………Crocodile Dundee
(from talkaboutsleep.com)
NightHawkeye.........oooh I can't think of anyone...Tom Hanks
RestedGal…….………….Joan Allen
Ric …………………………… Jim Carey
SAW…………………………..Kevin Bacon
telly……………………………Jon Lovitz
Denzel Washington …………..Denzel Washington

Special Guest Appearances:
Kavanaugh…………………….Sarah Jessica Parker
bookworm……………………. Kelly Ripa

[-SWS]

What does an APAP, or BiPAP detect? Answer: CHANGE. Change in pressure, change in flow, change in vibration. Correct?

So, I think we can agree, the diffuser is a static portion of the circuit. ...<snip>... the machine doesn't care. It's only looking for changes within the current configuration. If the machine couldn't do that, we'd have to have a different setting for EVERY variable within that circuit.

In my opinion SAG and Blarg have correctly pointed out the principle that static characteristics alone do not ensure unaltered system behavior. And to very correctly say that human respiration is alternating hints at an APAP system's steady state characteristics. However, human respiration and flow-based APAP input signals vary significantly in the transient time domain throughout each night. Transient, versus steady-state signal analysis, by the APAP algorithm itself is where the potential for skewed system output can result. When you see 420e runaway pressure abated by turning off IFL1, for instance, then you see the need to turn off a transient input signal that is virtually constant. Each APAP system is highly proprietary and highly transient-time-domain signal oriented. And a constant presentation of transient signal alteration does not always amount to unaltered system output.

So a legitimate question arises in my mind about whether any transient input signals are altered here. Does this in-line diffuser equate to several converging parallel venturi tunnels? If it does, what are the resulting transient-domain inspiratory wave shape ramifications based on multiple venturi convergences? Independent testing and verification is a great thing for PurSleep in my opinion. However, in my own opinion no black-box verification and testing can accurately predict a highly proprietary algorithmic (transient-domain affected) sustained system response across a highly "flow-signal-diverse" patient population. I do think transient flow signal alterations are worth duly noting and documenting.

I don't think the PurSleep difuser represents a significant danger of any kind to the public. I do think there may be some cases of altered system behavior and hence altered therapy because of subtle flow signal alterations. Again, on whole, I suspect that PurSleep is a good thing for many of us. This is, after all, a discussion board to discuss all things relevant to CPAP.

One other thing that's been largely ignored in this thread, is how people using Bret's system FEEL.

My take is that EO's either provide a positive subjective experience for you or they don't. If you fall in that latter category, you simply avoid using EO's. If you fall in that former category, then you continue using EO's and your CPAP compliance may very well be enhanced. But that's short-term. For many years there will continue to be unanswered long-term epidemiological questions about EO exposure. But that statement holds true for so many products throughout or household, including what's inside our refrigerator. If EO truly helps with CPAP compliance, then the long-term risks of CPAP non-compliance should be considered, at least at a personal level IMHO. But public health and welfare issues are also very worthy topics of consideration IMHO.

I know I've not been kind to Christine on this issue. That is an emotional response to someone directly interfering with my life. Someone who has absolutely no right to do so. I called her a twit and a drama queen. I still feel that way. (BTW, RG, if you're going to quote me, by all means use my name.)

Those of you who believe Christine's motives are "righteous" are being naive.

Recall from your past career in law enforcement that noble but burdensome jurisprudence concept known as "burden of proof". Rhetorically: why did this jurisprudence concept become a necessity in so many modern justice systems? The answer, I think, is to avoid the human tendency to incorrectly condemn based on mere superficialities. So how can anyone on a message board, of all places, definitively assign psychologic motives then publicly condemn perceived character traits?

I think the practice of attacking concepts, principals, and even methods, without attacking people best serve any rational forum or venue.

[-SWS]

OMG, OMG – PLEASE DON’T let it be over!
It’s better than GWTW!

Hey! You didn't buy the two-day pass!

[bookwrm63]

GFAD said:
Special Guest Appearances:
Kavanaugh…………………….Sarah Jessica Parker
bookworm……………………. Kelly Ripa

Kelly Ripa???? You couldn't do any better than that?

Ok..well perky, happy blonde is better than nothing!

Oh wait...I am a perky, happy blonde!

Mary

[Rabid1]

I think the practice of attacking concepts, principals, and even methods, without attacking people best serve any rational forum or venue.

Your point is very well taken. I attacked Christine personally, and I regret doing that.

Christine, please accept my public apology for the name calling. I've thought it over, and I feel bad about it.

Rick

[WearyOne]

Look out, brainstorm! The air intake entrainment idea...


SAG-'n-Sleep



WearyOne, I'll split the profits.

OK, let's do world hunger next.
SAG

SAG, you've got a deal!!

Let me know when we start on world hunger.

Pam

[-SWS]

That effect probably changes the flow by way of the Bernoulli Principle, creating a venturi effect

Okay. Having a closer look at pictures here. I admittedly can't tell just by looking at the picture below, but I don't think the venturi principle applies here. The cross-sectional area sum total of airflow passages (around the diffuser media) appears to equal or exceed that of the CPAP hose's diameter. I also suspect that DS would have pointed out the possibility of venturi effect if it existed here.

If there is any significant transient-domain flow-signal skewing here, then it would have to do with surface deflection. I am guessing that transient flow-signal alteration here is negligible. But therein lies one of the positive outcomes of PurSleep's independent verification IMO. It obviates potentially inaccurate guesswork about flow-signal alterations on our part.

[NightHawkeye]

The only thing left to do … would be to cast the movie version:

Working Title: One Flew Over the Sleep Apneas’ Nest

The most obvious cast member of all, Jack Nicholson, remains uncast . . ., although he's certainly the right age to have apnea, and he has an appropriately grumpy personality.

Hmmm . . ., (just wondering if any of the prime characters remains uncast . . .)

How about?
Snoredog ......................... Jack Nicholson

NightHawkeye.........oooh I can't think of anyone...Tom Hanks

Whew . . ., (NHE wipes sweat from his brow . . .) Thanks GFAD.

Regards,
Bill ( . . . wondering if he has any chance of living up to Tom Hanks' image)

[DreamStalker]

I have one, the cross-sectional area does exceed that of the hose by about two times.

hose x-sectional area = 0.8 inches-squared

x-sectional area of cotton pad = 0.2 inches-squared

max x-sectional area of diffuser = 2.3 inches-squared - area of cotton pad = 2.1 inches-squared

[-SWS]

I also suspect that DS would have pointed out the possibility of venturi effect if it existed here.

I have one, the cross-sectional area does exceed that of the hose by about two times.

Thank you, DS. I think that nicely answers venturi effect. That also satisfies impedence concerns. We're on to transient surface deflection issues, which I also suspect are negligible here.

[Snoredog]

Okay. Having a closer look at pictures here. I admittedly can't tell just by looking at the picture below, but I don't think the venturi principle applies here. The cross-sectional area sum total of airflow passages (around the diffuser media) appears to equal or exceed that of the CPAP hose's diameter. I also suspect that DS would have pointed out the possibility of venturi effect if it existed here.

If there is any significant transient-domain flow-signal skewing here, then it would have to do with surface deflection. I am guessing that transient flow-signal alteration here is negligible. But therein lies one of the positive outcomes of PurSleep's independent verification IMO. It obviates potentially inaccurate guesswork about flow-signal alterations on our part.

I don't think there is any venturi principle here either, if there was that would only speed up the velocity pressure through the device. The question is what the diffuser may do to signal curves used by the machine to respond to events. More specifically the safety grate which places a restrictive obstacle in circuit of flow.

Vibratory snore is one such signal, if the safety grate in the device dampens vibratory snore (any) the machine won't be able to detect them with the sensitivity it once did. Snore is easy to test, measure snore without the device in place then measure it again with it in place. Any loss in amplitude would provide the answer needed.

But snore is easy, and personally, I could care less about snores, but what we are looking at is WHAT impact the diffuser may or may not have on flow signal curves.

As you mentioned before these machines rely heavily on those signal curves, the Respironics Digital AutoTrak uses it almost exclusively on every one of its machines equipped with Biflex or Cflex and I'm sure even the newest Adapt SV machine will still use it. Even the basic Resmed machines use it as well.

It uses Volume triggers and Shape triggers. So not only does the device need to be measured for its impact on flow rates but also if it may modify the signal shape as that can trigger a different response from the machine.

Examples of Flow Volumes and Flow Shapes used by the Digital AutoTrak technology:

[-SWS]

More specifically the safety grate which places a restrictive obsticle in circuit of flow."

Restrictive as in a bona fine impedance concern? Based on Roberto's input above I don't think so.

The grating may have significant transient surface-deflective issues. Right about now I'm very seriously doubting that. Like you, Snoredog, I don't have one of these diffusers in my posession to make accurate physical assessments. Roberto's physical assessment sounds pretty fair to me right about now.

[roster]

For goodness sake, if I ever switch to an apap machine, am I to worry about "significant transient-domain flow-signal skewing" caused by the inlet tube on a particular mask I may be using; or the way I have that particular inlet tube hanging; or the curve in the six-foot hose? Look at the variety of masks on cpap.com and think about the varying ways we manage our inlet tubes and our air hoses. If apaps are "fooled" by the PurSleep in-line device then they must have even bigger problems with the other variables mentioned.

[DreamStalker]

Okay. Having a closer look at pictures here. I admittedly can't tell just by looking at the picture below, but I don't think the venturi principle applies here. The cross-sectional area sum total of airflow passages (around the diffuser media) appears to equal or exceed that of the CPAP hose's diameter. I also suspect that DS would have pointed out the possibility of venturi effect if it existed here.

If there is any significant transient-domain flow-signal skewing here, then it would have to do with surface deflection. I am guessing that transient flow-signal alteration here is negligible. But therein lies one of the positive outcomes of PurSleep's independent verification IMO. It obviates potentially inaccurate guesswork about flow-signal alterations on our part.

I don't think there is any venturi principle here either, if there was that would only speed up the velocity pressure through the device. The question is what the diffuser may do to signal curves used by the machine to respond to events. More specifically the safety grate which places a restrictive obstacle in circuit of flow.

Probably not much either ...

For goodness sake, if I ever switch to an apap machine, am I to worry about "significant transient-domain flow-signal skewing" caused by the inlet tube on a particular mask I may be using; or the way I have that particular inlet tube hanging; or the curve in the six-foot hose? Look at the variety of masks on cpap.com and think about the varying ways we manage our inlet tubes and our air hoses. If apaps are "fooled" by the PurSleep in-line device then they must have even bigger problems with the other variables mentioned.

Absolutely!

[-SWS]

If apaps are "fooled" by the PurSleep in-line device then they must have even bigger problems with the other variables mentioned.

As it turns out, sometimes APAPs do have problems with those other variables mentioned. Reference runaway pressure threads and plenty of patient-individualized complaints about any given APAP algorithm.

But I personally don't think PurSleep represents a signal skewing problem either. Rather I think PurSleep just may represent slight skewing of system output behavior. And if that slight skewing happens at all, then I would have to guess that it would be for patients who present signals near the "margins" of transient-signal detection for any given APAP.

Much incriminating flow-signal ado about nothing regarding this diffuser from what I can tell. And that is the purpose of my attempting to analytically delve in a little further.