CPAPtalk.com

[quote="MrGrumpy"][quote="DreamStalker"]APAP vs CPAP?

Grumpy is ... well, grumpy, and knows not what he mumbles about as grumpy people often do.

APAP does EVERYTHING a CPAP can do (an APAP can be set in CPAP mode) so an APAP too IS - "the gold standard" ... PLUS. APAP offers same exact treatment as CPAP with significantly more options (the PLUS part). Since your insurance pays 100%, the cost difference is a non-issue for you which should make your choice that much easier. Even if you paid 100% out-of-pocket, the APAP would still be the one to get if you had the cash flow to afford it.

As for blue lights, they don't bother me cuz I sleep with my eyes closed .... yes, I know, I'm weird that way. You can alway put a sock over the lights or do what Snoredog did and open the thing up and put electrical tape under the buttons on the inside.

HH, just go with the integrated. If you find you need more then get the HC150 off the auction site ... I got a spare there for less than $50 w/ shipping included.

I agree with ozij about resmed's "Autoset Algorithm" most likely being just a new name for their unchanged original algorithm (the "A10 algorithm") -- designed to not increase pressure above 10 when a full apnea is sensed.

That doesn't mean the machine can't treat people well. It's my understanding that ALL autopaps go about their work largely from a PREEMPTIVE standpoint. They all try to PREVENT apneas (and hypopneas) by sensing subtle changes (slight flow limitations) in the airflow from the person using the machine.

When autopaps sense a lessening of airflow (flow limitation) from you, they raise the pressure some. So, the resmed machine, just like any other autopap, could raise pressure well above a pressure of 10 to deal with flow limitations. Flow limitations could be indicators that an apnea is a'comin 'round the bend if you don't get the airway opened more.

Correcting the beginning of flow limitations (and the correction for those could be with pressures considerably above 10 cm) is intended to ward off apneas.

The resmed machine's design of "not gonna raise the pressure above 10 if an apnea happens" comes into play only if a sudden full apnea sneaks through. In that case, the resmed machine would just sit there waiting for the apnea to clear on its own.

Each brand of autopap has its own safety measure designed in so that the machine won't just keep raising pressure up, and up, and up, to no avail IF the "apnea" happens to be a central apnea rather than an obstructive apnea. The machines have no way to know for sure if an apnea is a central apnea -- where the throat is ALREADY open (brain has just not sent a signal, "Breathe now") and more pressure would NOT help.

To keep the autopap from upping the pressure unnecessarily in the face of a possible central apnea, these manufacturers put their own safety mechanism into the algorithm. As I understand it (I could be wrong):

resmed simply doesn't use pressure above 10 when a sudden apnea hits.

Puritan Bennett's 420E autopap has an advanced setting called "Max pressure for command on apnea" that comes from the factory set at 10. That advanced setting can be changed if a person needs it set higher or lower.

The Puritan Bennett 420E furthermore is designed to try to distinguish between "central" and "obstructive" apneas, through sensing cardiac oscillations (heartbeats) in the airflow. If heartbeats are sensed, the throat is open -- the machine figures it's a central apnea, not an obstructive apnea, and does not raise pressure.

According to the 420E's specs:
420e Central Apnea Specificity=100% (my note: That means, if it says a "Ca" happened, it really was a central.)
420e Central Apnea Sensitivity= 62%" (my note: That means, it's going to notice 62% of the centrals that could happen, and miss noticing 48% of them.)

As far as I know, the Puritan Bennett autopap is the only "regular" autopap that even attempts to distinguish between obstructive apneas and central apneas.

Respironics uses three small, increasing pressure nudges to see if an apnea "responds" to increasing pressure at all. If the airflow responds favorably by at least the third increase nudge, the machine considers it an obstructive apnea and fair game for more pressure to be used to clear it. If the airflow shows no sign of improvement after the third nudge, the machine assumes it might be a central apnea (throat already open) so, does not keep raising the pressure. It then marks that event on the data as "NR" (Non-Responsive) meaning more pressure (the three increasing pressure nudges) didn't get the airflow to improve at all.

"NR" on the Respironics software data might have been a central, or might not have been. I'd take it as, "yeah, that probably was a central."

My point is that all autopaps have their own way of avoiding increasing pressure unnecessarily if an apnea is really a central apnea (throat open, brain not saying "breathe now") instead of an obstructive apnea (throat collapsed shut.) If the throat is already open, but no airflow is happening, more pressure is not needed to open the throat -- it's already open.

Personally, I like the ways Puritan Bennett and Respironics chose to handle obstructive apneas and possible centrals, rather resmed's way of just capping the response at 10 if faced with a sudden apnea.

My understanding of those things may be off, or I may be explaining it poorly. -SWS and ozij understand the workings of the various autopaps far better than I do. I'd rely on what they say the machines do/don't do.

[quote="DreamStalker"][quote="MrGrumpy"][quote="DreamStalker"]APAP vs CPAP?

Grumpy is ... well, grumpy, and knows not what he mumbles about as grumpy people often do.

APAP does EVERYTHING a CPAP can do (an APAP can be set in CPAP mode) so an APAP too IS - "the gold standard" ... PLUS. APAP offers same exact treatment as CPAP with significantly more options (the PLUS part). Since your insurance pays 100%, the cost difference is a non-issue for you which should make your choice that much easier. Even if you paid 100% out-of-pocket, the APAP would still be the one to get if you had the cash flow to afford it.

As for blue lights, they don't bother me cuz I sleep with my eyes closed .... yes, I know, I'm weird that way. You can alway put a sock over the lights or do what Snoredog did and open the thing up and put electrical tape under the buttons on the inside.

HH, just go with the integrated. If you find you need more then get the HC150 off the auction site ... I got a spare there for less than $50 w/ shipping included.

rested gal wrote:It's my understanding that ALL autopaps go about their work largely from a PREEMPTIVE standpoint.

From prior discussions on the subject, it seems that none of the APAP machines responds immediately with a pressure increase, rather they all wait for the apnea event to clear before raising pressure further. I seem to recall that once an obstructive apnea occurs there's no reason to immediately raise pressure. The apnea must clear itself first because further pressure increases, if anything, would tend to maintain the apnea.

I think the main conclusion which can be drawn from the discussion so far is that APAP machines from the different manufacturers provide somewhat different treatment. Ostensibly, they all work well for most OSA patients, but the differences in treatment can be dramatic for some individuals under some circumstances.

The moral, Needsdecaf, is that if one brand of APAP doesn't work well for ya, then another very well might.

Regards,
Bill

rested gal wrote:I agree with ozij about resmed's "Autoset Algorithm" most likely being just a new name for their unchanged original algorithm (the "A10 algorithm") -- designed to not increase pressure above 10 when a full apnea is sensed.

That doesn't mean the machine can't treat people well. It's my understanding that ALL autopaps go about their work largely from a PREEMPTIVE standpoint. They all try to PREVENT apneas (and hypopneas) by sensing subtle changes (slight flow limitations) in the airflow from the person using the machine.

When autopaps sense a lessening of airflow (flow limitation) from you, they raise the pressure some. So, the resmed machine, just like any other autopap, could raise pressure well above a pressure of 10 to deal with flow limitations. Flow limitations could be indicators that an apnea is a'comin 'round the bend if you don't get the airway opened more.

Correcting the beginning of flow limitations (and the correction for those could be with pressures considerably above 10 cm) is intended to ward off apneas.

The resmed machine's design of "not gonna raise the pressure above 10 if an apnea happens" comes into play only if a sudden full apnea sneaks through. In that case, the resmed machine would just sit there waiting for the apnea to clear on its own.

Each brand of autopap has its own safety measure designed in so that the machine won't just keep raising pressure up, and up, and up, to no avail IF the "apnea" happens to be a central apnea rather than an obstructive apnea. The machines have no way to know for sure if an apnea is a central apnea -- where the throat is ALREADY open (brain has just not sent a signal, "Breathe now") and more pressure would NOT help.

To keep the autopap from upping the pressure unnecessarily in the face of a possible central apnea, these manufacturers put their own safety mechanism into the algorithm. As I understand it (I could be wrong):

resmed simply doesn't use pressure above 10 when a sudden apnea hits.

Puritan Bennett's 420E autopap has an advanced setting called "Max pressure for command on apnea" that comes from the factory set at 10. That advanced setting can be changed if a person needs it set higher or lower.

The Puritan Bennett 420E furthermore is designed to try to distinguish between "central" and "obstructive" apneas, through sensing cardiac oscillations (heartbeats) in the airflow. If heartbeats are sensed, the throat is open -- the machine figures it's a central apnea, not an obstructive apnea, and does not raise pressure.

According to the 420E's specs:
420e Central Apnea Specificity=100% (my note: That means, if it says a "Ca" happened, it really was a central.)
420e Central Apnea Sensitivity= 62%" (my note: That means, it's going to notice 62% of the centrals that could happen, and miss noticing 48% of them.)

As far as I know, the Puritan Bennett autopap is the only "regular" autopap that even attempts to distinguish between obstructive apneas and central apneas.

Respironics uses three small, increasing pressure nudges to see if an apnea "responds" to increasing pressure at all. If the airflow responds favorably by at least the third increase nudge, the machine considers it an obstructive apnea and fair game for more pressure to be used to clear it. If the airflow shows no sign of improvement after the third nudge, the machine assumes it might be a central apnea (throat already open) so, does not keep raising the pressure. It then marks that event on the data as "NR" (Non-Responsive) meaning more pressure (the three increasing pressure nudges) didn't get the airflow to improve at all.

"NR" on the Respironics software data might have been a central, or might not have been. I'd take it as, "yeah, that probably was a central."

My point is that all autopaps have their own way of avoiding increasing pressure unnecessarily if an apnea is really a central apnea (throat open, brain not saying "breathe now") instead of an obstructive apnea (throat collapsed shut.) If the throat is already open, but no airflow is happening, more pressure is not needed to open the throat -- it's already open.

Personally, I like the ways Puritan Bennett and Respironics chose to handle obstructive apneas and possible centrals, rather resmed's way of just capping the response at 10 if faced with a sudden apnea.

My understanding of those things may be off, or I may be explaining it poorly. -SWS and ozij understand the workings of the various autopaps far better than I do. I'd rely on what they say the machines do/don't do.

Well I had an experience recently that correlates well with what you and the others describe regarding the Resmed S8 Autoset Vantage APAP. A few months ago, I tried unsuccessfully to get on some testosterone gel my doctor prescribed me. What happened was the following:

I have my Resmed APAP set with a minimum pressure of 10, which is my titrated pressure from sleep lab. I add in the Androgel and if you dont know, testosterone is notorious for worsening OSA. Its in the testosterone literature. The first two weeks on Androgel, my max pressures start going all over the place...spiking up to 13, 14...even 15. This is every single night.

Normally, my max pressure spikes to 12, sometimes a little higher, sometimes a little lower.

Then, around the end of the second week on Androgel, my Apnea Index starts to EVERYDAY spike like crazy. Im having a minimum of 1 apnea event everyday, many days it was like 1.5 or even 2. Obviously, the Androgel was causing this.

As soon as my Apnea Index started spiking like I describe, my max pressures started to decrease like crazy. Around the beginning of the third week on Androgel, my max pressures are consistently around 11, rather than typical 12, 13, 14 or even 15 I was experiencing the first two weeks on Androgel.

When that happened, I began having dark rings under my eyes, began having restless sleep again and basically started feeling like a sleep deprived zombie.

At the beginning of the fourth week on Androgel, I gave up and stopped the Androgel. My pressures began to increase quickly and my Apnea Index normalized back to my typical "0." And I began feeling passable again.

I wondered what was happening and now I think I might know what was happening. Going by the descriptions of the Resmed APAP algorhythm, sounds like when the Androgel began spiking my Apneas to 1.o and above, the machine basically just cut me off at that mark.

Thats pathetic...I wonder what my hypoxia levels were those last two weeks on Androgel due to Resmed's failure to handle my increased apneas?

Eric

NightHawkeye wrote:

rested gal wrote:It's my understanding that ALL autopaps go about their work largely from a PREEMPTIVE standpoint.

From prior discussions on the subject, it seems that none of the APAP machines responds immediately with a pressure increase, rather they all wait for the apnea event to clear before raising pressure further. I seem to recall that once an obstructive apnea occurs there's no reason to immediately raise pressure. The apnea must clear itself first because further pressure increases, if anything, would tend to maintain the apnea.

Could you please point me to the discussion you got that from?

I'm not following why you quoted my statement about autopaps being designed to work preemptively -- preventing most apneas in the first place -- since you went on to talk about what you think an autopap will do if an apnea does occur.

Of course, how well autopaps can act preemptively depends in large part on getting the settings right in the first place -- especially the minimum pressure setting.

Anyway, if a sudden apnea hits, I don't think the REMstar Auto just sits there waiting for the apnea to clear. I could be wrong, but I think that's when it would begin its routine of using the first of three pressure increments to see if more pressure will improve the airflow. If one of the three pressure increases does improve the flow, it will continue (I think)using more pressure to get the airflow normal.

If that's the way it works, then the REMstar Auto is not just sitting there waiting for an apnea to clear on its own before doing anything else.

Of course if none of the three pressure increase nudges do anything to improve the flow, the machine will sit that one out, in case it happens to be a central apnea.

NightHawkeye wrote:I think the main conclusion which can be drawn from the discussion so far is that APAP machines from the different manufacturers provide somewhat different treatment. Ostensibly, they all work well for most OSA patients, but the differences in treatment can be dramatic for some individuals under some circumstances.

I agree.

NightHawkeye wrote:The moral, Needsdecaf, is that if one brand of APAP doesn't work well for ya, then another very well might.

Yep. Or even straight cpap (machine or mode) which could work even better for some people.

rested gal wrote:

NightHawkeye wrote:I think the main conclusion which can be drawn from the discussion so far is that APAP machines from the different manufacturers provide somewhat different treatment. Ostensibly, they all work well for most OSA patients, but the differences in treatment can be dramatic for some individuals under some circumstances.

I agree.

NightHawkeye wrote:The moral, Needsdecaf, is that if one brand of APAP doesn't work well for ya, then another very well might.

Yep. Or even straight cpap (machine or mode) which could work even better for some people.

I too agree.

And certainly Rested Gal's description of the different ways the companies handle the possibility "open airway" apneas fits in with what I've read.

O.

rested gal wrote:Could you please point me to the discussion you got that from?

I don't know if I dare, RG! How about we start over from scratch on this. This gives me an opportunity to examine a Respironics patent, something I've not done before.

A quick look at the flow chart for testing (by testing, they mean testing to decide whether or not to increase pressure), Figure 7, in Respironics patent 5,645,053, AUTO CPAP SYSTEM AND METHOD FOR PREVENTING PATIENT DISTURBANCE USING AIRFLOW PROFILE INFORMATION, reveals that whenever an apnea is sensed, the control system abstains from any further pressure increases. The same response to abstain occurs if a hypoventilation event (i.e., possible central apnea) is sensed. A written description of this operation is also provided.

rested gal wrote:Anyway, if a sudden apnea hits, I don't think the REMstar Auto just sits there waiting for the apnea to clear.

Actually, RG, that is what the machine does, and the written description in the patent says that. On page 12, 2nd column, line 61: "If an apnea, hypoventilation or respiratory variation error is detected during the testing, the testing mode is exited and the system goes directly to the holding pressure of the previous non-testing period."

I'm certainly no expert on the matter, but the Respironics patent is written in understandable language and the operation of the testing algorithm seems clear enough.

Regards,
Bill

NightHawkeye wrote:

rested gal wrote:Could you please point me to the discussion you got that from?

I don't know if I dare, RG! How about we start over from scratch on this. This gives me an opportunity to examine a Respironics patent, something I've not done before.

A quick look at the flow chart for testing (by testing, they mean testing to decide whether or not to increase pressure), Figure 7, in Respironics patent 5,645,053, AUTO CPAP SYSTEM AND METHOD FOR PREVENTING PATIENT DISTURBANCE USING AIRFLOW PROFILE INFORMATION, reveals that whenever an apnea is sensed, the control system abstains from any further pressure increases. The same response to abstain occurs if a hypoventilation event (i.e., possible central apnea) is sensed. A written description of this operation is also provided.

rested gal wrote:Anyway, if a sudden apnea hits, I don't think the REMstar Auto just sits there waiting for the apnea to clear.

Actually, RG, that is what the machine does, and the written description in the patent says that. On page 12, 2nd column, line 61: "If an apnea, hypoventilation or respiratory variation error is detected during the testing, the testing mode is exited and the system goes directly to the holding pressure of the previous non-testing period."

I'm certainly no expert on the matter, but the Respironics patent is written in understandable language and the operation of the testing algorithm seems clear enough.

Regards,
Bill

You just piqued my curiosity with that quote, Bill. Actually, that section does not describe the machine's response to an apnea. Rather that section describes the algorithm's premptive search for optimum versus critical pressure. That little pre-emptive search toward an optimum "pressure holding pattern" occurs when the algorithm is not otherwise preoccupied responding to a sleep event, NR, variable breathing, etc. (all different parts of the algorithm).

Specifically, the Remstar Auto periodically performs little pressure-delta tests, searching for tell-tale variations in the flow signal. All toward differentiating an "optimum" holding pressure versus understanding a "critical" pressure threshold below which subtle hints of adverse flow variations are detected. The idea is for the algorithm to detect those subtle flow variations and to not cross below that threshold---rather to keep the "pressure holding pattern" at just a slightly higher "optimum". This part of the algorithm speaks of achieving the lowest and presumably most comfortable holding pressure that is safely afforded.

I think Rested Gal is right about that three-pressure-increment limit in direct response to an apnea. After that limit of three pressure increments in response to an apnea, it is either resolved (in three or fewer pressure attempts) or it is labeled as non-responsive (NR).



I also agree with Rested Gal that the Resmed A10 algorithm leverages preemptive apnea treatment. That means an obstructive apnea that resolves at higher than 10 cm is often preemptively eliminated by that algorithm as long as typical snores and/or flow limitations serve the algorithm as precursor indicators.

I don't think I agree with the statement that people having apneas resolved by CPAP higher than 10 cm are ill-served by A10. Specifically, it would be those people who atypically have no snore and no FL precursors and require apnea resolution at pressures higher than 10 cm who would be poorly served by A10. To simply meet that atypical failing requirement for just a small yet significant portion of the night still means that A10 is probably not your best choice. But as Bill correctly points out, IMHO, all the APAP algorithms have their respective little efficacy shortcomings that tend to be manufacturer-specific.

I ain't sayin' I'm right. I'm just sayin' that's my opinion. .

I went to the Auto Algorithm software training program (that many of us downloaded some time ago) and re-typed the following, verbatim, from it. I'll let you all draw your own conclusions, but it doesn't appear to be an "immediate" response to me.....based on the number of events it has to see over a given period of time, depending on which events it's detecting.

Den

------------------------------------------------------------------------------------

From the Event Responses section:

Flow Limitation response:
While in Ptherapy mode, if flow limitation occurs during the last 4 breaths or over several minutes, the algorithm begins a Popt search

Vibratory snoring:
In Ptherapy mode, if 3 vibratory snores are detected within 1 minute, with less than 30 seconds between snores, the algorithm increases pressure by 1 cmH2O over 15 seconds.
Re-initiate Ptherapy for 5 minutes.
Further vibratory snoring-related increases are limited to 1 cmH2O per minute.

Apnea/Hypopnea:
While in Ptherapy mode, if 2 apneas/hypopneas are detected within 3 minutes, the algorithm increases pressure by 1 cmH2O
Re-initiate Ptherapy for 5 minutes

In Popt search mode, if 2 apneas/hypopneas are detected within 3 minutes, the algorithm increases pressure by 1 cmH2O.
Re-initiate Ptherapy for 5 minutes.

Non-Responsive:
Above 8 cmH2O pressure, the pressure increase for sustained apneas/hypopneas is limited to 3 cmH2O above the pressure setting at the onset of the apnea/hypopnea sequence.
The pressure setting at the onset of the sequence is called the "Onset Pressure".
The pressure 3 cmH2O above the "Onset Pressure" is called the "NRAH Threshold".
"NRAH" is an acronym for "Non-Responsive Apnea/Hypopnea".

------------------------------------------------------------------------------------

Exception Condition:
The persistence of large leaks, particularly when the patient's breath have small tidal volumes, could potentially induce false apnea and hypopnea detection. Therefore the REMstar Auto monitors the patient's flow over several minutes.
The patient's flow is compared to "expected leak". "Expected leak" is a value that has been determined through testing of various mask and tubing combinations.

------------------------------------------------------------------------------------

-SWS wrote:

NightHawkeye wrote:

rested gal wrote:Could you please point me to the discussion you got that from?

I don't know if I dare, RG! How about we start over from scratch on this. This gives me an opportunity to examine a Respironics patent, something I've not done before.

A quick look at the flow chart for testing (by testing, they mean testing to decide whether or not to increase pressure), Figure 7, in Respironics patent 5,645,053, AUTO CPAP SYSTEM AND METHOD FOR PREVENTING PATIENT DISTURBANCE USING AIRFLOW PROFILE INFORMATION, reveals that whenever an apnea is sensed, the control system abstains from any further pressure increases. The same response to abstain occurs if a hypoventilation event (i.e., possible central apnea) is sensed. A written description of this operation is also provided.

rested gal wrote:Anyway, if a sudden apnea hits, I don't think the REMstar Auto just sits there waiting for the apnea to clear.

Actually, RG, that is what the machine does, and the written description in the patent says that. On page 12, 2nd column, line 61: "If an apnea, hypoventilation or respiratory variation error is detected during the testing, the testing mode is exited and the system goes directly to the holding pressure of the previous non-testing period."

I'm certainly no expert on the matter, but the Respironics patent is written in understandable language and the operation of the testing algorithm seems clear enough.

Regards,
Bill

You just piqued my curiosity with that quote, Bill. Actually, that section does not describe the machine's response to an apnea. Rather that section describes the algorithm's premptive search for optimum versus critical pressure. That little pre-emptive search toward an optimum "pressure holding pattern" occurs when the algorithm is not otherwise preoccupied responding to a sleep event (a different part of the algorithm altogether).

Specifically, the Remstar Auto periodically performs little pressure-delta tests, searching for tell-tale variations in the flow signal. All toward differentiating an "optimum" holding pressure versus understanding a "critical" pressure threshold below which adverse flow variations are detected.

I think Rested Gal is right about that three-pressure-increment limit in direct response to an apnea. After that limit of three pressure increments in response to an apnea, it is either resolved (in three or fewer pressure attempts) or it is labeled as non-responsive (NR).



I also agree with Rested Gal that the Resmed A10 algorithm leverages preemptive apnea treatment. That means an obstructive apnea that resolves at higher than 10 cm is often preemptively eliminated by that algorithm as long as typical snores and/or flow limitations serve the algorithm as precursor indicators.

I do not agree with the statement that people having apneas resolved by CPAP higher than 10 cm are ill-served by A10. Specifically, it would be those who atypically have no snore or FL precursors and require apnea resolution at pressures higher than 10 cm who would be poorly served by A10. But as Bill correctly points out, IMHO, all the APAP algorithms have their respective little efficacy shortcomings that tend to be manufacturer-unique.

snoredog wrote:and how would it differentiate a Flow Limitation at those higher pressures say above 10 cm?

I'm not sure exactly what you're getting at with the above question, Snoredog.

Are you saying that machine pressure above 10 cm somehow skews the patient flow signal (making FL signal differentiation impossible)?

Or rather are you saying that if a machine's pressure happens to be above 10 cm that flow limitations don't happen?

Or perhaps you are saying that Wally used A10 and it never responded to his flow limitations above 10 cm?


The rest of your post I view as valid opinion. Although I noticed the timing of some of those opinion-changes seems to have coincided with MAP just a teensie bit, eh? .

-SWS wrote:

snoredog wrote:and how would it differentiate a Flow Limitation at those higher pressures say above 10 cm?

I'm not sure exactly what you're getting at with the above question, Snoredog.

Are you saying that machine pressure above 10 cm somehow skews the patient flow signal (making FL signal differentiation impossible)?

Or rather are you saying that if a machine's pressure happens to be above 10 cm that flow limitations don't happen?

Or perhaps you are saying that Wally used A10 and it never responded to his flow limitations above 10 cm?


The rest of your post I view as valid opinion. Although I noticed the timing of some of those opinion-changes seems to have coincided with MAP just a teensie bit, eh? .

The above questions are more related to supposedly the preemptive treatment of events.

I only pointed out that FL's can be seen at high pressure as well as low and that a FL doesn't necessarily develop into a Hypopnea and a Hypopnea doesn't develop into a apnea.

We also know if you snore there is a darn good chance that if an apnea is likely to occur, it will happen on inhale right after that snore (reason why most machines chase snores so aggressively).

Hey wait a minute, I just answered my own questions about the only preemptive treatment you can expect from these machines is if it accidently does so responding to another type of event like a snore.

come to think of it, they ALL do that

But they're not accidentally responding to snore or FL. They are intentionally responding to snore and flow limitation with pressure increases, trying their flawed best to make sure those obstructive apneas never happen.

On the interesting subject of Wally's flow limitations at high pressures... I'm still of the opinion this can happen two ways: 1) passive relaxation of muscle mass (remiss active airway maintenance), and 2) reflexive partial airway closures (neurological control gates activated toward closure).

I think gravity predominately drives scenario one and defensive/reflexive neurology drives scenario two. And I think scenario two is more prominent in OSA than medicine has recently suspected. Now that's wild man speculation!

Scenario one is an easy job for CPAP but sometimes scenario two can be "reflexively challenging" for ordinary PAP to resolve. I suspect cyclic alternating pattern (CAP) may even be characteristically hyperactive during reflexive scenario two. Again, pure wild speculation.

[quote="-SWS"]But they're not accidentally responding to snore or FL. They are intentionally responding to snore and flow limitation with pressure increases, trying their flawed best to make sure those obstructive apneas never happen.

On the interesting subject of Wally's flow limitations at high pressures... I'm still of the opinion this can happen two ways: 1) passive relaxation of muscle mass (remiss active airway maintenance), and 2) reflexive partial airway closures (neurological control gates activated toward closure).

I think gravity predominately drives scenario one and defensive/reflexive neurology drives scenario two. And I think scenario two is more prominent in OSA than medicine has recently suspected. Now that's wild man speculation!

Scenario one is an easy job for CPAP but sometimes scenario two can be "reflexively challenging" for ordinary PAP to resolve. I suspect cyclic alternating pattern (CAP) may even be characteristically hyperactive during reflexive scenario two. Again, pure wild speculation.