CPAPtalk.com

Guest (assuming you are KLM)

But my PB330 (the one you linked to) does not have a T mode only. It has S Mode & S/T mode (they call it A/C but it is the same. ?

Also do you have any links that explain the speed with which say, the Remstar increases its pressure the moment a flow cessation event is detected. ?.

Cheers

DSM

dsm wrote:Guest (assuming you are KLM)

No, that wasn’t me, but I’m flattered by the assumption.

dsm wrote:Question: "Which home BiLevels allow the user to set them exclusively into T mode ?"

Off the top of my head, a couple examples of such bi-levels are the Respironics Synchrony and the Resmed Sullivan VPAP ST-A.

dsm wrote:Also do you have any links that explain the speed with which say, the Remstar increases its pressure the moment a flow cessation event is detected. ?.

I would suggest you scour the patent to see how the interval between detection and increased pressure is determined via the different algorithms in place. Perhaps that would give you an idea of the speed at which it can occur.

dsm wrote:If you were a proven sleep specialist I *might* be willing to explain a lot more about what was occuring with the observations of my wife and the studies that I conducted

If you are willing to make claims for all who read this forum to see, but are unwilling to back them up and explain them to anyone who is not a proven sleep specialist, then I would politely suggest you might want to refrain from making such claims on a forum comprised primarily of individuals who are not sleep specialists and might be unduly influenced by your statements, and who may not yet know enough to question them. Certainly, you could not have expected your statements to be accepted without skepticism.

Back to the original issue. I think while you're questioning how much one can rely on apap detection, you must logically also question how much one can rely on visual observation. You claim your apap machine's data was inaccurate and "not scientific by a long shot" because it was in disagreement with your wife's visual observations of your breathing. Was she was charting your breathing variations each time she observed them throughout all your sleeping hours on each machine by documenting the exact time they occurred, the pressure at which they occurred, how many seconds they lasted, whether or not (as best she could tell) there was any respiratory effort, if the pressure changed, the amount of time until the next complete breath stoppage, etc.? I'm assuming you compared her charts containing this data acquired by visual observation with the data as reported by the software and tried to match up what she perceived to be events with events recorded from the apap. Is this the method you employed which lead you to question the veracity of the data reported by your apap? I must admit I am more inclined to question the accuracy of such methodology than I am inclined to assume poor detection on the part of the apap.

Again, I would ask, in the absence of even a single central apnea event during your PSG, wouldn't it be logical to assume the stopped breathing your wife observes is caused by obstructive apnea, not central apnea? I don't understand your assumption that, in your case, this is the result of CSA or Mixed Apnea and not the result of your clinically diagnosed OSA.

It is possible your self-diagnosis of Mixed Apnea may have missed the mark. As was explained, the experiment you performed with your apap was invalid unless the "settling period" criteria had been met. There are previous posts on this subject if you'd like to research it. Also, relying on your wife's observations as evidence of central apnea is invalid, since it is not always humanly possible to visually differentiate between stopped breathing which results from obstructive apnea vs. central apnea. In addition, your assertion the apap data was inaccurate because it did not corroborate your hypothesis of central or mixed apnea is problematic because, in fact, all verifiable evidence points to the likelihood it is your hypothesis which may be inaccurate. If indeed you are experiencing some central apneas, (which only a PSG could confirm), rest assured the majority are normal physiologic events.

If you choose to make assumptions about the type of apneas you are experiencing based on visual observation, certainly that is your personal business. However, when you use this forum to publicly warn apap users, "can be lulled into thinking the data from their machine is scientific when it is nowhere near so," while admitting you reached this conclusion based on the fact that the data did not coincide with your wife's unscientific visual observations as a means of diagnosing central apnea, you invite intense scrutiny.

KLM wrote:
If you are willing to make claims for all who read this forum to see, but are unwilling to back them up and explain them to anyone who is not a proven sleep specialist, then I would politely suggest you might want to refrain from making such claims on a forum comprised primarily of individuals who are not sleep specialists and might be unduly influenced by your statements, and who may not yet know enough to question them. Certainly, you could not have expected your statements to be accepted without skepticism.

KLM,

I am willing to back up my claim if only you would stick to a single point and let us finish it.

It was you who tried to publicly rebut my remarks - 2 core ones being

1) That if you take the time to conduct a simple test with your Remstar AUTO where you slow then stop your breathing, the AUTO does nothing !.

2) That an AUTO doesn't start the user breathing again after the user has stopped breathing.

You attemted to rebutt both these assertions. You also tried to dodge issue 2 by claiming that you were not meaning centrals in regard to 2 and I kindly let you off the hook. Well I will go further and state that in 2 above even if caused by an obstruction, an AUTO does not normally (nor is it designed to) 'start the user breathing again'.

You in your arrogance have fallen for the same trap many people have. An AUTO does not recover a user from an immediate instance of stopped breathing due to either central or an obstructive apnea. An AUTO attempts *very slowly* to adjust its CMS to prevent the *next* occurence. It is too slow to react to an immediate occurence.

#added
But, a BiLevel with S/T, can try to clear both a central and an obstruction!. I think we already agree on that point.

I am telling you my position on this is correct and that you are typically jumping to conclusions.

I can prove my position and will present a new thread within days showing a study done with 4 AUTOs and simulated stopped breathing. I will make the effort to prove my statement versus your arrogant insistence that you are right merely because you say so.

Also, the reason you will never be willing to post the time it takes an AUTO to respond to a blockage is either because
- You don't know & won't admit it and don't understand the significance
- You do know but realised that if you admitted it it shoots down your argument that AUTOs will start a user breathing again.

But in your characteristic fashion I expect you will, once you realise (or have already realised) the fallacy in your position, merely deny that is what you meant.

Also once we can get an admission re how an AUTO actually works when a user stops breathing, I can return to point of my wife's observations because from where I see this she has highlighted issues that you clearly don't understand or have got embarrassingly wrong.

Cheers

DSM
PS why won't you register so we can discuss this privately as without PM, you are blocking the opportunity to sort this out privately. By remaining public, it leaves me with little option but to rub your nose in your fallacy

_________________

CPAPopedia Keywords Contained In This Post (Click For Definition): auto

_________________

CPAPopedia Keywords Contained In This Post (Click For Definition): auto

KLM wrote:Off the top of my head, a couple examples of such bi-levels are the Respironics Synchrony and the Resmed Sullivan VPAP ST-A.

Interesting, My Respironics BiPap S/T will operate in S or S/T mode. So how do I set it into T only mode.

My reading of the manual for the VPAP indicates it operates the same way. S or S/T mode. But am willing to accept your are correct if you can find any part of the manual the contrdicts my belief re this.


DSM

dsm wrote:But am willing to accept your are correct if you can find any part of the manual the contrdicts my belief re this.

DSM, you are capable of looking this up too. Anyone can.

The Respironics Synchrony (from their literature)

Spontaneous (S)—This is a bi-level mode which
responds to both your inhalation and exhalation by
increasing pressure when you start to inhale and
decreasing pressure when you start to exhale. There is no
automatic delivery of a breath should you not inhale.

Spontaneous/Timed (S/T)—This is an optional bi-level
mode which responds to both your inhalation and
exhalation by increasing pressure when you start to inhale
and decreasing pressure when you start to exhale. If you
do not start inhaling within a set time, the Synchrony will
automatically start inhalation. When the Synchrony starts
inhalation, it controls the time of inhalation and
automatically decreases the pressure for exhalation within
a set time.

Timed (T)—This is an optional bi-level mode in which
the Synchrony controls both inhalation and exhalation
independent of spontaneous breathing.
-------------------------------------------------------------------------------------
And the Resmed Sullivan VPAP ST-A from their literature:

Modes of Operation
The VPAP II ST-A can be operated in four different ways:
1. Spontaneous/Timed mode - VPAP II ST-A operates in Spontaneous mode with Timed mode as a backup.

2. Spontaneous mode - VPAP II ST-A accurately senses patient breathing patterns and switches between pressures accordingly.

3. Timed mode - VPAP II ST-A delivers IPAP and EPAP pressures at a predetermined breathing rate.

4. CPAP mode - VPAP II ST-A delivers constant positive airway pressure

dsm wrote:It was you who tried to publicly rebut my remarks - 2 core ones being

1) That if you take the time to conduct a simple test with your Remstar AUTO where you slow then stop your breathing, the AUTO does nothing !.

2) That an AUTO doesn't start the user breathing again.

Not "tried to rebut", but, in fact, did rebut. Go back and read the posts. The answers are there.

Now, let's try, yet again, to get your response. Back to the original issue. I think while you're questioning how much one can rely on apap detection, you must logically also question how much one can rely on visual observation. You claim your apap machine's data was inaccurate and "not scientific by a long shot" because it was in disagreement with your wife's visual observations of your breathing. Was she was charting your breathing variations each time she observed them throughout all your sleeping hours on each machine by documenting the exact time they occurred, the pressure at which they occurred, how many seconds they lasted, whether or not (as best she could tell) there was any respiratory effort, if the pressure changed, the amount of time until the next complete breath stoppage, etc.? I'm assuming you compared her charts containing this data acquired by visual observation with the data as reported by the software and tried to match up what she perceived to be events with events recorded from the apap. Is this the method you employed which lead you to question the veracity of the data reported by your apap? I must admit I am more inclined to question the accuracy of such methodology than I am inclined to assume poor detection on the part of the apap.

Again, I would ask, in the absence of even a single central apnea event during your PSG, wouldn't it be logical to assume the stopped breathing your wife observes is caused by obstructive apnea, not central apnea? I don't understand your assumption that, in your case, this is the result of CSA or Mixed Apnea and not the result of your clinically diagnosed OSA.

It is possible your self-diagnosis of Mixed Apnea may have missed the mark. As was explained, the experiment you performed with your apap was invalid unless the "settling period" criteria had been met. There are previous posts on this subject if you'd like to research it. Also, relying on your wife's observations as evidence of central apnea is invalid, since it is not always humanly possible to visually differentiate between stopped breathing which results from obstructive apnea vs. central apnea. In addition, your assertion the apap data was inaccurate because it did not corroborate your hypothesis of central or mixed apnea is problematic because, in fact, all verifiable evidence points to the likelihood it is your hypothesis which may be inaccurate. If indeed you are experiencing some central apneas, (which only a PSG could confirm), rest assured the majority are normal physiologic events.

If you choose to make assumptions about the type of apneas you are experiencing based on visual observation, certainly that is your personal business. However, when you use this forum to publicly warn apap users, "can be lulled into thinking the data from their machine is scientific when it is nowhere near so," while admitting you reached this conclusion based on the fact that the data did not coincide with your wife's unscientific visual observations as a means of diagnosing central apneas, you invite intense scrutiny.

dsm wrote:If you were a proven sleep specialist I *might* be willing to explain a lot more about what was occuring with the observations of my wife and the studies that I conducted

You have made it evident to all of us you have no intention of "explaining a lot more". There is a valuable lesson to be learned here. If you are unwilling to discuss the premise you present, it would be prudent not to present it in the first place.

Thanks KLM, on that issue I accept that the Synchrony does work differently to my BiPap S/T (which is supposed to be the later model of the same machine).

Re this whole thread on how AUTOs deal with stopped breathing and your issue re my wife's observations, I am willing to offer a peace overture before we let it slip any further in more counter punches.

If you will highlight a single issue you want me to deal with, and we negotiate and agree on how that will happen, I will point out a single issue I want you to deal with and we can negotiate and agree on how we will deal with right down to eliminating ambiguous meanings.

I am sure we are both smart & mature enough to do this in a way respectful of the other's points - something I feel that has been lacking thus far (on both sides).

In fact I believe we will both learn a lot. I am concerned in particular at how many people misunderstand how AUTOs work and what their actual design purpose was and how they go about it. I am a researcher and a former engineer so tend to go about my research in fairly scientific ways and am always willing to vary the research and to accept that some hypotheses are different from what is expected.

Let me know if you are willing to take this step.

I would still prefer you to register so we can PM each other to help avoid public squabbling over details.

Cheers

DSM

dsm wrote:If you will highlight a single issue you want me to deal with, and we negotiate and agree on how that will happen, I will point out a single issue I want you to deal with and we can negotiate and agree on how we will deal with right down to eliminating ambiguous meanings.

DSM,
Will this require that we meet unarmed? On neutral ground? Switzerland, perhaps? I hope you're kidding, but something tells me you're not. I find it most peculiar you feel it necessary to treat this as some sort of Peace Accord wherein your responses will only be forthcoming through your defined terms of negotiation. This is a message board where people come to learn. We ask questions and we answer questions. I have answered every question you have asked, though clearly not to your satisfaction. Since my responses are not to your liking, I would suggest you start a new thread asking the same questions. I'm sure you'll get many replies, inciting a lively educational discussion and inviting many new questions; that is, of course, provided the poster is not made to feel the answer is going to be held hostage pending the release of reciprocal information. "I'll tell you the details of the experiments I constantly reference in which I claim it is possible for my wife to discern the type of apneas I'm having by watching me as I sleep and which I use as the basis for my claim that apap data is not scientific or accurate, but only if you tell me how the timing of the algorithms works for the flow sensors on an apap." The answers you're withholding are answers only you can give. No one else can tell us about your experiments. The answers you require in your trade agreement are answers that anyone can look up, but require a great deal of time and research. Seems a bit onerous, don't you think?

The information regarding the algorithms can be obtained by anyone willing to take the time to research the patent. You continue to imply the auto cannot sense stopped breathing and cannot react to it. There's no way to sugarcoat it; you're wrong. Per the patent, via the flow sensors, it can and does. You asked how long it takes to sense this and take action by increasing pressure. I have researched the patent for you and it says:

Once flow limitation is observed the pressure is increased 1.5 cm in 15 seconds and P therapy is initiated.

Regarding your experiments; I seriously doubt anyone will have the tenacity to pursue it now that we've seen (after 5 pages) you don't care to reveal any of the details. Unless, of course, you bring it up again in the future, which would be be viewed as an indication that you welcome questions on the subject.

KLM

So its no is it ? -- dealing with clearly defined and specific issues one by is to hard is it ?

There was a good reason I have suggested we pinpoint a specific issue and that is because you

1) Jump to conclusions. Your leaps of logic don't instill confidence in me in dealing with you - yet another example is your statement of fact that I diagnosed myself with mixed apnea.
KLM I will agree to you asking me this question
"DSM do you have central or mixed apnea" but guess what - you haven't yet asked that question but you saw fit to publish an answer from me !!!

Is that jumping to conclusions or is it that you are blinded by a personal agenda such as attacking people who attempt to do their own sleep analysis ? - I am led to believe the latter. A good reason to treat any interaction with you very cautiously.

If you had asked me that question I would *not* have given the answer you so presumptuously published.

If you asked me
"DSM to you think you have mixed apnea" I would give yet a different answer and add lots of qualifications. But you didn't ask me directly either question. Certainly not in an agreed interaction on the topic. But it seems you already know all the answers !.


2) You have clearly shown you lack of an ability to concede a point. You dodge the issue when the evidence begins to show you may have got it wrong. That is yet another reason I would want to handle public interaction with you by establishing specific questions in advance.

But lets explore the issue of AUTOs having the ability to get a user with a blockage breathing again (an issue you still won't concede on) ...

In this reply...
>>
I have researched the patent for you and it says:
Quote:
Once flow limitation is observed the pressure is increased 1.5 cm in 15 seconds and P therapy is initiated.
<<

It says 15 seconds once a flow limitation is observed. I don't know where you got this & for what machine, I don't know in what context it is being stated but I can tell you it is direct conflict with my real world experiments with my AUTOs (I have 4). So what do we do here, do I believe your 'words' or do I believe my eyes, or do I pretend that what I am seeing isn't happening ?.

Your position on the issue of getting a user breathing again after a flow limitation just doesn't bear out in the real world. AUTOs are designed to prevent blockages by anticipating them they are not designed (yet) to try to correct a blockage in-flight, only the user can & does do that. AUTOs prepare for blockages by sensing for pre-blockage conditions (snores) and each machine has its own algorithm and its own strengths and weaknesses in achieving this.

As for pure flow-limitations ...
The Remstar in my tests will do nothing if I slow and stop breathing *unless* before I go through the stop, I snore quite a few times. In my tests it took over 90 seconds for the Remstar to raise its CMS by 1. And that was after lots of continuous snoring & snorting and simulated choking.

What AUTOs do is to 'correct' a pattern of breathing, not individual blockages. You seem to have misinterpreted the manufacturer's word 'correct' to mean it fixes a block on the spot by raising the pressure so the user can start breathing again (I expect you will deny this is what you meant). The fact is that AUTOs are too slow to respond. It is the user's own breathing that will correct the detected blockage well before the AUTO has adjusted, but by adjusting, the AUTO is attempting to anticipate the next blockage by rasing the positive airway pressure to a level that will hopefully prevent subsequent blockages. They don't always succeed 1st go and it may take several events before the AUTO has raised the pressure enough to be effective at correcting.

One reason I tell people with AUTOs is *NOT* to set them with a range of 4 to 20. This too me is plain stupid & any sleep therapist that puts machines out with those settings is ignorant as well as stupid. With that kind of range there is a very high probability that the user will suffer several events before the AUTO slowly attempts to correct the pattern. Have you not noticed the numbers of people who come into cpaptalk and complain that they don't feel that much better with their new AUTO - usually it was given to them set 4-20 - all the wise heads in cpaptalk say set your AUTO 3down3up (I prefer it to be even tighter at 2down2up). We can the ask why this particular situation arises ? - it is because the AUTO is generally and some in particular, are too slow to adjust to the inital apea blockages.


***************

I have 4 AUTOS and I have taken the time to conduct several types of expriments with each of them. Of my machines, the Resmed Spirit responds fastet to snores & snorts followed by a simulated blockage but even it took 40 seconds to increase the CMS by 2 cms.

The Resmed spirit as with the Remstar did nothing when I slowed & stopped my breathing without preceeding this with snores or snorts. Same with the other 2 AUTOs (a Tranquility AUTO & a Cloud Nine AUTO).

I am will to share these experiments here and even vary them or try different ways of testing them and if you were smart enough you would be willing to explore these tests through me rather than you characteristic dictating to me how you know this process works.

********************

You do come across as both sanctimonious and opinioned rather than genuinely interested in learning from us. You really don't seem willing to give some of us the benefit of the doubt on general points. You manner on this board is that of an unfriendly inquisitor.

But back to the value of my wife's observations:
How do you think I decided to try these tests. It gets back to what my wife was observing - which I then tried simulating & also analysing the data from at that time both the Remstar and the Resmed. These two machines gave conflicting results on AI vs HI and quite different AHI indexes. So here I am a user interested in my therapy and what may be happening analysing conflicting data on HI & AI. what conclusions do you imagine I might come to. I did further tests & decided the Resmed was inline with my wifes observations.

I will be mystified if you can't see this analysis and approach as a sound and reasonable way of looking at my own situation. So why didn't I go into more detail before, because as I said, I don't know who you are, what you are, and what your questionable agenda is. IMHO you seemed to have a cocked up understanding of how AUTOs work so I had and still have no confidence in discussing anything with you in detail *unless* it is speecific and unless you give as much value as you demand.

I am sure you know what my specific question to you would be about. Here is an example ...
- "KLM, can you explain in say 10 points how an AUTO, timed in seconds, reacts to a specific flow limitation from the instant it occurs - lets assume the AUTO is set for low=10, upper=18 and titration for user of 15"

I would be very interested in you step by step analysis and timing.

But at the moment I understand this approch is to purile for you ? true ?

***************

Also why won't you register and use PM ??? - that is another aspect that leaves me with doubts about your agenda & sincerity. There seems to be a distinct lack of it.

Cheers

DSM

_________________

CPAPopedia Keywords Contained In This Post (Click For Definition): resmed, Titration, AHI, auto

DSM's personal experience is just that: his personal experience. It does not alter the facts.

DSM didn't feel his OSA was successfully treated with the REMstar Auto. One man's personal experience does not disprove the well-established fact that apaps are capable of performing the functions of detection and correction. It proves only that DSM felt it did not work for him.

Ideally, the pressure range is set appropriately to prevent all events. This is not always possible as all events do not necessarily occur gradually enough to be prevented. When an event is not prevented, (e.g. stopped breathing caused by an obstructive apnea as indicated by restricted airflow) this is detected by the algorithms used by the manufacturer. The pressure is raised to open the airway, breathing resumes and the event is corrected. If the event is not corrected (e.g. stopped breathing caused by a central apnea event) the different manufacturers use different criteria to determine how to proceed. (This has already been previously discussed in this thread.)

With regards to the breath-holding experiment with the REMstar Auto:

-SWS wrote:This variable-breathing detection controller also explains why some people have posted that they unsuccessfully tried to fool their Remstar Auto into triggering on simulated apneas by intentionally halting their breath while still awake: while wide awake and experimenting they wouldn't have presented that highly regular breathing pattern characteristic of slumber.

viewtopic.php?p=16259#16259

-SWS wrote:Recall that as soon as you turn on any AutoPAP it incurs a "settling period". During that initial time frame the Remstar Auto will not react to sleep events, genuine or artificial (with the possible exception of snore, which is highly indicative of sleep). I believe the Remstar Auto's settling period is defined by some quantified sequence of respiratory cycles (perhaps with additional respiratory criteria thrown in as well---I actually forgot) as opposed to the 420e or Spirit. These latter two models define a settling period simply using the criteria of time alone.

The Remstar Auto also has a variable breathing controller which can detect a change in the cadence or rhythm of breathing. The variable breathing controller will first try to normalize the respiratory rate, then it will go into a fifteen minute "sit out" period in which it will not address any sleep events, genuine or artificial. The breathing pattern changes that occur during the transition from sleep to wake just may be enough to trigger that variable breathing controller as Wader suggests. Or highly variable breathing that might occur while awake regardless of prior sleep may be enough to trigger that variable breathing controller. In either case simulated apneas will not trigger the machine.

I would expect the 420e likely employs some kind of similar algorithmic controller that cautiously suspends pressure increases when irregular or highly variable breathing is present. If so, that controller or even the 420e's fifteen-minute settling period would be potential impediments to fooling the 420e with an artificial apnea.

viewtopic.php?t=2561


The REMstar Auto's detection and correction method:
REMstar Auto with C-Flex Algorithm Reference Guide:

P critical Mode: defines pressure level where airway begins to collapse utilizing 0.5cmH20 drop per minute pressure slope + flow limitation trending calculations. Once flow limitation is observed the pressure is increased 1.5 cm in 15 seconds and P therapy is initiated.

-SWS wrote:Remstar Auto Algorithmic technique for but a SINGLE sleep apnea event:
===================================================
1) apnea detected,
2) increase pressure for the first time
3) measure patient airflow
4) if airflow reflects "unresponsive" or uncorrected condition, increase pressure for the second time
5) measure patient airflow,
6) if airflow reflects "unresponsive" or uncorrected condition, increase pressure for the third time
7) measure patient airflow
if airflow still reflects "unresponsive" or uncorrected condition, decrease pressure for fear of inducing central apneas

viewtopic.php?p=11966#11966



The ResMed AutoSet's detection and correction method:
The AutoSet Algorithm

Preemptive Response

AutoSet devices act preemptively by increasing pressure in response to inspiratory flow limitation, which typically precedes snore and obstruction. This early intervention prevents snoring and obstructive apneas, thereby reducing respiratory arousals.

Sudden Apnea Response

Apneas may occur suddenly, without being preceded by flow limitation or snore. These sudden apneas are generally associated with sleep onset, change in body position, or REM onset. Following a sudden apnea, AutoSet devices will increase pressure relative to the severity of the event. If no further events occur, AutoSet devices reduce the pressure back to a minimum level.

The AutoSet Algorithm

The efficacy of the AutoSet algorithm is due to its ability to increase pressure in response to the severity of the three parameters (flow limitation, snore, and apnea):

The greater the flow limitation, the more pressure delivered
The louder the snoring, the more pressure delivered
The longer the apnea, the greater the increase in pressure
By responding to these three separate parameters, AutoSet devices effectively normalize sleep while delivering a mean pressure typically 37% lower than fixed pressure therapy.

The fact that apaps are capable of detection and correction is indisputable. DSM's personal experience is an example of how some individuals prefer one machine's algorithms over another. While the majority of users should feel confident they will receive effective treatment with any apap, DSM feels he, personally, did not receive effective treatment with the REMstar Auto. The issue here is not capability, but rather the personal dissatisfaction with this particular machine specifically for DSM.

The above long post by anon (whoever) is a very nice tidy post & has lots of well presented data.

There are some points I feel it attempts to address that need far better explanation that the presented text achieves -

In this post I will address the item giving a step by step response of an AUTO to a single event.

The REMstar Auto's detection and correction method:
REMstar Auto with C-Flex Algorithm Reference Guide:
Quote:
P critical Mode: defines pressure level where airway begins to collapse utilizing 0.5cmH20 drop per minute pressure slope + flow limitation trending calculations. Once flow limitation is observed the pressure is increased 1.5 cm in 15 seconds and P therapy is initiated.


-SWS wrote:
Remstar Auto Algorithmic technique for but a SINGLE sleep apnea event:
===================================================
1) apnea detected,
2) increase pressure for the first time
3) measure patient airflow
4) if airflow reflects "unresponsive" or uncorrected condition, increase pressure for the second time
5) measure patient airflow,
6) if airflow reflects "unresponsive" or uncorrected condition, increase pressure for the third time
7) measure patient airflow
if airflow still reflects "unresponsive" or uncorrected condition, decrease pressure for fear of inducing central apneas

viewtopic.php?p=11966#11966

Words are great on paper, but if those words don't coincide with actual use, then there is a problem. Also, I know what settling time is. I did all my tests after 20 mins prone use of the machine in question. On the Resmed I can program or remove the settling time. To be fair I set a minimum of 20 mins in a steady prone (on my back) use before trying the experiments.

So at this time I am willing to take advice on how to change the experiments, but if anyone says, "oh, but to truly test this situation you can only do it when asleep", I will reply that that is a cop out.

My 1st comment is that there are *no* times included (seconds in each stage) without the times the sequence is wishful thinking if it takes more than 60 or so seconds from start to finish, I am positing that in the elapsed time as described, the user will have recovered breathing themselves before the AUTO has increased pressure. AUTOs are not as fast as T mode BiLevels at responding to a flow limitation. That is an undisputable fact.
My test to date can't better 40 secs to raise a Resmed 2 cms no matter what patterns of breathing I try. In my tests the Resmed *is* faster to respond than a Remstar.

If someone has some suggestions re how I can vary my tests I am more than willing to try these suggestions against the reality of the machine's reaction.

Also I am not intending posting the data to just targeted one brand of AUTO, I am targeting defects in the behavior of any machine. My 1st machine was a Remstar AUTO and it has a lot of great features. If I had to choose between using my Resmed AUTO and the Remstar AUTO, the Remstar would win out just on the quietness (requested by my wife), as hen I used the Resmed Spirit (S7 style) she would go sleep in another room (actually the slight whine didn't bother me excessively).

Also re the other threads on BiPap flipping. My criticism of these machines is because of how they behave, not their brand. The fact that I spent 1000s of $s on a BiPap S/T states where I thought my therapy direction lay. It came as a rude shock to me to find the machine had a pressure flipping problem that I haven't fully solved. I even bought another Bipap to compare yet a 3rd one. It did not surprise me to have other people stepping forward and claiming they had similar problems.

I see myself as more like a Ralph Nader of xPAP , if any brand of machine appears to have defects and I have purchased a machine that seems to have defects, once I have enough evidence I will approach the vendor to discuss. Also I will have no hesitation in discussing here in cpaptalk.

More later on other excerpts in the anon post.

DSM

(what is it with some folk that they won't register & identify themselves in some form ???)

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CPAPopedia Keywords Contained In This Post (Click For Definition): resmed, bipap, C-FLEX, auto

With regards to the breath-holding experiment with the REMstar Auto:
-SWS wrote:
This variable-breathing detection controller also explains why some people have posted that they unsuccessfully tried to fool their Remstar Auto into triggering on simulated apneas by intentionally halting their breath while still awake: while wide awake and experimenting they wouldn't have presented that highly regular breathing pattern characteristic of slumber.

viewtopic.php?p=16259#16259

I am well aware of how my breathing changes as I relax and go off to sleep. I have had many years of listening to others go to sleep. With 5 children I'd say I have a very good idea of how people breathe when asleep.

So what is the point of the above ?.

If it is to put the position that no one awake can emulate sleeping breathing then it is once again a cop-out. I am satisfied an awake person can do a a fair job of emulating sleeping breathing patterns.

The pure flow-restriction tests I carried out were as close as I could get to what happens when I go off to sleep and were as close as I could get to match the situation my wife was describing to me about how I was 'slowing breathing, then stopping'.

Again,

I am willing to vary the experiments. Let me have some suggestions.

DSM



DSM

The ResMed AutoSet's detection and correction method:
The AutoSet Algorithm
Quote:
Preemptive Response

AutoSet devices act preemptively by increasing pressure in response to inspiratory flow limitation, which typically precedes snore and obstruction. This early intervention prevents snoring and obstructive apneas, thereby reducing respiratory arousals.

Sudden Apnea Response

Apneas may occur suddenly, without being preceded by flow limitation or snore. These sudden apneas are generally associated with sleep onset, change in body position, or REM onset. Following a sudden apnea, AutoSet devices will increase pressure relative to the severity of the event. If no further events occur, AutoSet devices reduce the pressure back to a minimum level.

The AutoSet Algorithm

The efficacy of the AutoSet algorithm is due to its ability to increase pressure in response to the severity of the three parameters (flow limitation, snore, and apnea):

The greater the flow limitation, the more pressure delivered
The louder the snoring, the more pressure delivered
The longer the apnea, the greater the increase in pressure
By responding to these three separate parameters, AutoSet devices effectively normalize sleep while delivering a mean pressure typically 37% lower than fixed pressure therapy.

The fact that apaps are capable of detection and correction is indisputable.

Aha ! - so does this explain why the Autoset may be quicker to respond than a Remstar ?

But!, I am wanting to prove that even those words can be matched in real life with one of those machines. How does the Resmed machine 'pre-empt a snore 'is it clairvoyant ? (a joke) - people change their breathing flow continuously as the night progresses. My breathing is slow & deep when I start off to sleep but in parts of the night goes shallow and slow then can go shallow & faster. These patterns if not including snores don't seem to change the pressure of the machine.

The only way I have thus far seen the CMS change is when airflow oscillations are induced (simulated snoring) and simulated chokes (gagging & snorting).

Re AUTOs addressing individual apneas, again we have a poster claiming that an AUTO can adjust its CMS once having decided a flow limitation has occurred, quicker than the average apnea event lasts. I say prove it. I believe I can repeatedly prove the opposite.

I fear that the anon poster here is trying to mystify the process of breathing and how AUTOs work in order to obscure some harsh realities about their effectiveness.

DSM

The fact that apaps are capable of detection and correction is indisputable.

This is a statement of the obvious.

But what does correction mean. That it can do it instantly, or corrects patterns.

That wording is a big trap that can be palmed off to mean something it doesn't.

A T mode Bilevel can respond to an immediate flow-limitation in as little as 4 secs.

An AUTO doesn't. It takes a lot longer and requires a set of pre-conditions. An AUTO is good at averaging treatment and thus correcting from an event that has already occured. But this is not a big deal. So AUTOs are slower than CPAPs & BiLevels !.

The average apnea blockage is only a few seconds.

It is that simple.

DSM

#PART 2

Lets us look at the three main types of xPAP and see how fast they deal with OSA (centrals are a different issue)

1)
A CPAP set at the titration level for a user is (providing the titration was adequate) already maintaining a Positive Airway Pressure that is adequte to prevent OSA. So we could say that a CPAP is preventing OSA.

2)
A BiLevel with T mode can detect a flow limitation and as I can prove (in this instance I can match the claims of the manual for the PB330), will flip from EPAP to IPAP in 4 seconds and because the IPAP CMS is usually the established titration CMS required for this user, may be able to fix the blockage. But the question has to be asked, how did could an OSA blockage have happened if the user was already at the PosAirPressure required. But because the EPAP to APAP flip has he potential to clear a detected blockage it can be said to be able to resolve immediate blockages

3)
An AUTO will try to look for breathing patterns that indicate an impending OSA blockage based on a set of programmed probabilities.
A) One breathing pattern is the airflow oscillations associated with snoring and this is combined with variations in the volume of user's airflow. The louder the snoring the greater the airflow oscillation & the higher the AUTO will rate the pattern and sooner or later the AUTO will take action. (at dispute here in this thread is the speed with which this occurs **(see bottom)).
B) Another airflow pattern is declining airflow without oscillations such as might happen with a central.

One trap some people fall for is to believe an AUTO can correct a central by raising the pressure. The simple fact is that raising the pressure does not command the user to breath again !!!. I believe we have agreement on this trap in thinking.

If an AUTO can detect an OSA blockage and can raise the pressure, the issue becomes how much pressure is needed to clear a blockage and how fast the AUTO can start raising the pressure once it has decided there is a problem requiring increased pressure.

If the AUTO was at 6cms and the pressure needed to effectively clear the blockage is 12 then it would have to go through its decision making cycle approx 12 times do do steps of 0.5 cms.

However we look at it, the AUTO is in many instances reacting after the event and in the best possible circumstances may be quick enough to clear a long blockage if it was already close to the required CMS needed but in most cases the user would have gone through an arousal and recommenced breathing on their own before the AUTO got to the needed CMS BUT, the AUTO is now positioned to deal better with the next event. It could take several such events before the AUTO is at the same pressure the CPAP & BiLevel were at all along!. So while the claim says that AUTOs correct OSA blockages, the word is loose enough to me that it may take servar goes to do so. I believe it is fair to say an AUTO chases events and eventually will 'correct' them (being a pattern of blockages or OSA events).

DSM


**
The heart of this current part of this thread is the speed with which AUTOs act. Essentially it seems neither side has put forward convincing proof of their case.
The side arguing an AUTO can fix an immediate blockage is using broad descriptions & interpretations of words like 'corrects' to prove their case but words aren't enough to do so. My argument is that I have done tests that can show results but I accept that some people may not be willing to accept those tests. I then say well put forward some tests you will accept.

The standoff will be if no test I conduct is ever acceptable & that to me would be a poor way to try win the argument. I am not willing to accept just the words when the tests I conduct can't back them up.


## One additional condition. I will not invest *any* time performing tests requested by an unregistered poster or an unknown registered poster.

If I am going to invest time & effort & money the least I expect in return is that the requestor offer something in return. The starting thing i will require is my insistance they are a regular registered member of cpaptalk (no instant phantoms, no guests, no anons). Just people with the courage to identify themselves. so simple !.
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CPAPopedia Keywords Contained In This Post (Click For Definition): Titration, Arousal, CPAP, auto

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CPAPopedia Keywords Contained In This Post (Click For Definition): Titration, Arousal, CPAP, auto

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DSM didn't feel his OSA was successfully treated with the REMstar Auto. One man's personal experience does not disprove the well-established fact that apaps are capable of performing the functions of detection and correction. It proves only that DSM felt it did not work for him.

Now come on. This remark is distorting what the issue is about. Once again we have this anon poster saying what I am thinking and experiencing. No
I am not focussing on the Remstar AUTO per se, I am focussing on AUTOs and how they work.

And this wording(which at least shifts back to the true focus of AUTOs in general) is yet another distortion...

does not disprove the well-established fact that apaps are capable of performing the functions of detection and correction

My experience and my opinions don't change any facts - how stupid!.
My opinions & tests *do* challenge the meaning of 'correction' in the context it is being used!. How many times do I have to state this !.
How many ways do I have to state it ?.

I do resent it when words get manipulated to create an impression that is not correct. Just like that statement that I 'said' I had diagnosed myself with mixed apnea - to be blunt that posting was a lie. There is no post I made anywhere in this whole thread that justified that lie in any form.

If you plan to win arguments with lies & distortions I will challenge you and expose them but it does indicate what I am dealing with. Perhaps it also explains why you lack the courage to post under a real cpaptalk id

Cheers

DSM

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