420E Run Question ???

Bill,

-you have no real snoring taking place, so that is not driving up pressure
-you don't really seem to have a problem with CA's from that report,
-while the Flow limitations are logging pretty heavily, the machine with those setting doesn't seem to be trending pressure up.

What happens to those runs if you drop Initial to 7.0 cm? You would also need to move Minimum to 7.0 for it to be effective.

IF you want to address those frank apnea and hypopnea, I would even consider increasing the A10 to like 12, you can see where it stopped at 10cm at hour 91 on that double Hypopnea/Apnea, that is clearly the "Maximum" pressure allowed to address an Apnea. Bump it to 12 cm from current 10 and it will go higher.

Sorry, but I don't buy into Ozij's theory on how this machine handles Hypopnea, it is addressed just like Apnea governed by the same A10 command on apnea parameter, not Flow Limitation. Flow Limitation is specific with specific flattening seen, it is how the machine detects it and it how it is explained in the patent.

These parameters just like the parameters found on the bipap auto create "rules" that have to be considered when setting up the machine. While the Bipap Auto from Respironics does a better job with those rules by not allowing some settings to take place, the 420e has no program limitation but it impacts how the machine responds.

So.... in my theory

FL1=is unchecked if you want to stop the machine from responding to stand-alone Flow Limitation.
FL2=is unchecked if you want to stop the machine from responding to Flow Limitation associated with a Hypopnea (HI+FL)
A10 Maximum Command on Apnea= Maximum "delivery" pressure delivered when an Apnea/Hypopnea is seen. IF this is set for 13 cm, then the machine will move up to 13 cm pressure in presence of an apnea, by default it only moves to 10 cm in the presence of these events "when" no Cardiac Oscillation is detected.

You do NOT need to worry about the 420e responding to Central Apnea, BUT you have to watch that A10 parameter "command on Apnea" pressure doesn't start to trigger them for the 38% of apnea where it may be used.

Those nearly constant Flow limitations seen may not mean anything and be a result of shallow breathing. Shallow breathing would show up as Flow Limitation and the more severe it becomes even Hypopnea.

The 420e can be made "aggressive" or non-aggressive in the presence of those FL's. You would probably not do very well on a Resmed Autoset machine because it too chases Flow Limitation and Snore with no mercy. It is why I could never use the Spirit, but my FL runs are not as severe as yours appear to be.

If you can tolerate it, I would like to see how you do at 7.0 cm on the Minimum and Initial side, that may even be better for your aerophagia.

As far as apnea is concerned (apnea/hypopnea) you can pretty much let the machine go on those, if any CA's show up it won't respond to them.

I know this thread is more for the "brainiacs" (said with total respect, BTW) and not for the still fairly uneducated, like me, but I am desperately trying to understand this more so that I can feel better, so if you will indulge my stupid questions, I would appreciate it.

I've just watched the movie once again that shows the different breathing disruptions, and I understand the hypopnea is 50% of normal flow. How does the 420E then count a hypopnea as flow limited also? Because, in my brain anyway, it would seem that hypopnea is a step up from flow limited already. The air coming through the extra little tube in the P.B. hose is what's determining how much air flow there is. Right? So is it, say, plain old flow limitation is at 40% of normal, hypopnea is 50% of normal, hypopneas with flow limitation is 60-80% of normal, on up to the 90% normal for an apnea? Am I getting this at all?

So question about the "flow limited cycle". How does that work? When I'm now getting some pretty decent AHIs, why is my borrowed 420E spending so much time in the flow limited cycle (anywhere from 42 to 57%)? The events aren't that many compared to the hours of sleep I'm getting, but doesn't that length in that cycle indicate that it's detecting some sort of "problem" to deal with? (Sorry about the quotes, but I'm assuming it's in that different than normal cycle because it perceives a problem.)

And why I'm trying to figure this out is that, between O., RG, and myself, I've gotten to a place in the last three nights where I have NO apneas!! Whoohoo! But I am still having some centrals popping up, and my doctor thinks they are "event related", so that kind of comes down to the hypopneas then in the last few days, and I'm wondering what I can adjust to make those go away also. I know -- I want the world! So I'm thinking if I can figure out what adjustments affect the hypopneas, then I can eliminate the centrals (and I'm hoping the aerophagia, under my theory that mine is caused from certain events making me gulp more air in), and then one of these days, I am going to wake up and say, "Holy sh*t! I actually feel GREAT this morning!!!"

If I'm asking for too much instruction at dufus level here, I apologize. I can read and read and read the documentation, but it's in one ear and out the other because my brain is just not that technically gifted. So if someone can put it into layman's terms and maybe offer a tweak here or there, I'd appreciate it. I am currently at 11 initial, 11 minimum, 14 maximum, 12 command on apnea, and IFL on.

(BTW, I should note the centrals do not appear to be pressure related for me. I have them anywhere from 8 to 14, in my experience. So I think my doc is right that they are event related, although there is that little niggle of doubt when I see one pop up all by its lonesome on the charts. At least there haven't been enough of them to show up on the 420E to get anyone too excited at this point.)

Thanks for your help!

Peggy

snoredog wrote:..how this machine handles Hypopnea, it is addressed just like Apnea governed by the same A10 command on apnea parameter

So.... in my theory

A10 Maximum Command on Apnea= Maximum "delivery" pressure delivered when an Apnea/Hypopnea is seen. IF this is set for 13 cm, then the machine will move up to 13 cm pressure in presence of an apnea, by default it only moves to 10 cm in the presence of these events "when" no Cardiac Oscillation is detected.

Okay. So I agree with your interpretation that cardiac oscillation is used to distinguish between a closed-airway apnea (presumed obstructive) and an open-airway apnea (presumed central).

But rhetorically... how is cardiac oscillation used to distinguish between an obstructive hypopnea and a central hypopnea? Both hypopnea types entail an open airway. That means both hypopnea types do not readily lend differentiation by simply discerning an open airway via cardiac oscillation detection.

And if hypopneas cannot be readily differentiated by the same method that apneas are differentiated, then how can we say the 420e handles apneas and hypopneas the same?

pjwalman wrote:I know this thread is more for the "brainiacs" (said with total respect, BTW) and not for the still fairly uneducated, like me, but I am desperately trying to understand this more so that I can feel better, so if you will indulge my stupid questions, I would appreciate it.

I've just watched the movie once again that shows the different breathing disruptions, and I understand the hypopnea is 50% of normal flow. How does the 420E then count a hypopnea as flow limited also? Because, in my brain anyway, it would seem that hypopnea is a step up from flow limited already. The air coming through the extra little tube in the P.B. hose is what's determining how much air flow there is. Right? So is it, say, plain old flow limitation is at 40% of normal, hypopnea is 50% of normal, hypopneas with flow limitation is 60-80% of normal, on up to the 90% normal for an apnea? Am I getting this at all?

So question about the "flow limited cycle". How does that work? When I'm now getting some pretty decent AHIs, why is my borrowed 420E spending so much time in the flow limited cycle (anywhere from 42 to 57%)? The events aren't that many compared to the hours of sleep I'm getting, but doesn't that length in that cycle indicate that it's detecting some sort of "problem" to deal with? (Sorry about the quotes, but I'm assuming it's in that different than normal cycle because it perceives a problem.)

And why I'm trying to figure this out is that, between O., RG, and myself, I've gotten to a place in the last three nights where I have NO apneas!! Whoohoo! But I am still having some centrals popping up, and my doctor thinks they are "event related", so that kind of comes down to the hypopneas then in the last few days, and I'm wondering what I can adjust to make those go away also. I know -- I want the world! So I'm thinking if I can figure out what adjustments affect the hypopneas, then I can eliminate the centrals (and I'm hoping the aerophagia, under my theory that mine is caused from certain events making me gulp more air in), and then one of these days, I am going to wake up and say, "Holy sh*t! I actually feel GREAT this morning!!!"

If I'm asking for too much instruction at dufus level here, I apologize. I can read and read and read the documentation, but it's in one ear and out the other because my brain is just not that technically gifted. So if someone can put it into layman's terms and maybe offer a tweak here or there, I'd appreciate it. I am currently at 11 initial, 11 minimum, 14 maximum, 12 command on apnea, and IFL on.

(BTW, I should note the centrals do not appear to be pressure related for me. I have them anywhere from 8 to 14, in my experience. So I think my doc is right that they are event related, although there is that little niggle of doubt when I see one pop up all by its lonesome on the charts. At least there haven't been enough of them to show up on the 420E to get anyone too excited at this point.)

Thanks for your help!

Peggy

zero AHI? looks like to me you are effectively treated for OSA.

Still have CA's with an auto setup to function as a CPAP?

Take that 96hr printout to your doctor and show them how well you do on CPAP at 11 cm pressure because that is what you really have.

Pressure induced centrals will show up as a train wreck all bunched together, usually a sign of unstable sleep. So if that condition regularly presents itself at a similar pressure you know that is your threshold for pressure, yours was 13.

Random CA's (one or two) don't really mean anything and may be exactly what your doctor says post-arousal centrals, they show up right after an event like an apnea, but with proper use of the machine and manipulation of pressure you should be able to prevent the apnea that leads to the CA's.

So really the only thing you need to avoid is the pressure that leads to the train wreck and allow the machine to take care of the rest.

So now you are essentially using straight CPAP pressure settings (what you get when you set Minimum pressure to 11 or near your titrated pressure) do you feel any better?

My guess is NOT, if you were you would probably have said I feel GREAT!!

It is my speculation you went over the hill and are stuck on the other side.

Snoredog wrote:What happens to those runs if you drop Initial to 7.0 cm? You would also need to move Minimum to 7.0 for it to be effective.

I've had both the Initial and Minimum below 7. The result was less aerophagia, but more events. I'm inclined to try this, Snoredog, because it might just help both aerophagia and the eustachian tube clogging I experience. Both are helped by lower pressures. I suspect it will raise the number of events though and to minimize that I'll need to raise the Initial pressure to 8.5 or so. Hmm ..., this is beginning to sound suspiciously like where I was just a couple of weeks ago ...

Snoredog wrote:IF you want to address those frank apnea and hypopnea, I would even consider increasing the A10 to like 12, ... Bump it to 12 cm from current 10 and it will go higher.

That's new! It's certainly worth a try. Assuming that the machine is catching central events there should be little reason not to do so.

Snoredog wrote:Those nearly constant Flow limitations seen may not mean anything and be a result of shallow breathing. Shallow breathing would show up as Flow Limitation and the more severe it becomes even Hypopnea.

The 420e can be made "aggressive" or non-aggressive in the presence of those FL's. You would probably not do very well on a Resmed Autoset machine because it too chases Flow Limitation and Snore with no mercy. It is why I could never use the Spirit, but my FL runs are not as severe as yours appear to be.

I'm gonna have to do some serious reading on the hypopnea, flow-limitation and flow-limitation runs algorithms for PB. I hear the words, they make sense, but not all the dots are connecting yet for me.

I don't yet grasp how the machine responds to hypoventilation relative to the reference level. I suspect that the runs are really an indication that the reference airflow level is going up and down. Like I said, I gotta read through the Rapoport patent(s) and try to understand more of the details.

Thanks for the comments, Snoredog.

Regards,
Bill

pjwalman wrote:I know this thread is more for the "brainiacs"

Umm ..., NO. I think maybe the reason you say this is because the folks on this forum using the PB420E tend to be more experienced CPAP users who, after trying other machines, have concluded that the 420E is simply the most capable unit. [FLAME suit ON]

I am pleased though that this thread has remained sufficiently interesting to run as long as it has and attracted so many participants. While my questions about flow-limitation runs have not been completely answered, a wealth of sharing has occurred.

Don't feel bad about not understanding all this stuff. Neither does anyone else here. Each of understands bits and pieces of it. (Some more than others, of course.)

Regards,
Bill

SnoreDog, I'd respond except I don't have a clue how to do that to what you wrote. I sense the derision, of course, but I don't see constructive suggestions of what to do differently. I didn't say zero AHI -- I said zero apneas. Three days in a row of no plain-old apneas is a first for me -- pardon me for being excited about it. If I thought I was cured, why in the hell would I subject myself to your insults by asking my stupid questions so that I could better understand? I guess I'm supposed to go running off with my tail between my legs because I've exposed my stupidity in this thread. Sorry! Wasn't the first time, won't be the last, and brow-beating me won't get rid of me. I'll keep reading and trying to figure things out. Though maybe not in this thread as it looks like I stepped into something I should have kept my dainty little shoes out of.

Peggy

NightHawkeye wrote: Don't feel bad about not understanding all this stuff. Neither does anyone else here. Each of understands bits and pieces of it. (Some more than others, of course.)

What Bill said.

I think that also describes the situation among practitioners and researchers in sleep medicine. Even those bona fide braniacs don't understand the complete picture. Nor do they always agree. Being able to put diverse views and experience together---even when those views disagree---is extremely important IMHO.

And Peggy seems to be picking this stuff up very quickly. So how soon before she's teaching us?

-SWS wrote:And Peggy seems to be picking this stuff up very quickly. So how soon before she's teaching us?

Uhh ..., I'm already learning, -SWS. Have I mentioned before that I'm about as dumb as a box of rocks?

pjwalman wrote: I've just watched the movie once again that shows the different breathing disruptions, and I understand the hypopnea is 50% of normal flow. How does the 420E then count a hypopnea as flow limited also? Because, in my brain anyway, it would seem that hypopnea is a step up from flow limited already.

Your brain got it right, Peggy. Generally airway obstructions occur in progressive shades of severity. A flow limitation is slight airway narrowing. An obstructive hypopnea is even more airway narrowing (of adequate duration). And an obstructive apnea is either a full airway closure or very close to being a full closure (also of adequate duration).

pjwalman wrote:The air coming through the extra little tube in the P.B. hose is what's determining how much air flow there is. Right?

That little tube is hooked up to the pressure sensor inside the machine. The big tube is hooked up to the flow sensor. And you are right that flow is what the machine measures to determine obstructive events.

pjwalman wrote: So question about the "flow limited cycle". How does that work? When I'm now getting some pretty decent AHIs, why is my borrowed 420E spending so much time in the flow limited cycle (anywhere from 42 to 57%)?

Well, clearly it's going to boil down to a case of either false positives or genuine persistent airway narrowing. We've discussed one possible way that Bill might be measuring FL false positives on his machine. Shallow breathing (central hypoventilation) as snoredog suggests might be yet a second hypothetical way for the 420e to score FL false positives. I'm sure there are plenty of other hypothetical ways we can dream up to skew that inspiratory wave shape into scoring FL false positives on the 420e.

But let's consider the case of genuine persistent flow limitations for a moment. We're talking slight airway narrowing. And that can be predominately static or dynamic in nature. In the Resmed presentation we pretty much see the dynamics of airway narrowing occur. However, some patients have airway characteristics that are inherently narrow to start with. SDB patients falling into that latter category can very easily spend higher percentages of the night with flow limited cycles than the rest of us.

Most people with obstructive SDB experience some mix from that full spectrum of events: flow limitations, hypopneas, and apneas. However, those with inherently narrow airways (characteristic of UARS) can genuinely have significantly more flow limited cycles than typical apnea and hypopnea patients.

pjwalman wrote: And why I'm trying to figure this out is that, between O., RG, and myself, I've gotten to a place in the last three nights where I have NO apneas!! Whoohoo!

That is worth celebrating. Great progress! It's not a given that everyone with outstanding flow limitations suffer with significant daytime symptoms. It's a virtual certainty that outstanding flow limitations will in some way impact your sleep architecture.

Now that you have apneas and hypopneas in better control, you might be surprised at how much better you feel by day. However, many genuine UARS patients discover that outstanding flow limitations adversely affect how they function and feel by day. And the fact that quite a few sleep clinics today virtually ignore UARS diagnosis and proper treatment leaves quite a few patients in the lurch, IMO.

Of course, we have no way of knowing whether you have an inherently narrow airway or genuine UARS characteristics. You may get to the point where you want to solicit a second opinion about your SDB. If you do, consider finding out which sleep clinics in your area diagnose and treat UARS.

NightHawkeye wrote:

-SWS wrote:And Peggy seems to be picking this stuff up very quickly. So how soon before she's teaching us?

Uhh ..., I'm already learning, -SWS. Have I mentioned before that I'm about as dumb as a box of rocks?

LOL! Bill, you've always been one very smart cookie in my book!

And not many days before Peggy overtakes us!

-SWS wrote:

snoredog wrote:..how this machine handles Hypopnea, it is addressed just like Apnea governed by the same A10 command on apnea parameter

So.... in my theory

A10 Maximum Command on Apnea= Maximum "delivery" pressure delivered when an Apnea/Hypopnea is seen. IF this is set for 13 cm, then the machine will move up to 13 cm pressure in presence of an apnea, by default it only moves to 10 cm in the presence of these events "when" no Cardiac Oscillation is detected.

Okay. So I agree with your interpretation that cardiac oscillation is used to distinguish between a closed-airway apnea (presumed obstructive) and an open-airway apnea (presumed central).

But rhetorically... how is cardiac oscillation used to distinguish between an obstructive hypopnea and a central hypopnea? Both hypopnea types entail an open airway. That means both hypopnea types do not readily lend differentiation by simply discerning an open airway via cardiac oscillation detection.

And if hypopneas cannot be readily differentiated by the same method that apneas are differentiated, then how can we say the 420e handles apneas and hypopneas the same?

ozij wrote:And remember how Derek (with a preponderance of hypops) found he did much better on the Respironics' fixed mode than on auto.

I do remember that, ozij. And quite a few posters have also discovered that same trend, leading to your valid observations expressed in another thread:

ozij wrote:The way to handle too many hypopneas on an auto is to raise the minimal pressure.

And some people with a preponderance of hyponeas do better at fixed pressure.

ozij wrote:Wild assumptions:
Somtimes (Always?) IFL1 follows the slope method - depending on percentage of flow limited breaths?

Doesn't seem so wild from my perspective.

ozij wrote:When a person has a larger percentage of flow limited breaths (etiology unknown) and IFL is on, Max. is meant to be be capped?

Well, this "large percentage" situation sure seems to happen often enough. And I've been wondering if Rapoport intended UARS obstruction to at least receive an attempt at "muscling through" with high pressure. Clearly "muscling through" with high pressure is going to cause a variety of problems for different patients. But does maximal pressure ever yield increased efficacy for those patients with high upper airway impedance who also happen to be high-pressure tolerant? I'm admittedly inclined to think that it seldom does if ever.

However, a patient with high upper airway impedance is not necessarily a UARS patient. To be a UARS patient, there also needs to be arousals and especially symptoms associated with those flow limitations. If you don't have significant arousals, desats, or symptoms to go with those flow limitations, then what's the point in attempting to treating the FL with high pressures?

But I'm also disinclined to believe that highly symptomatic UARS patients, who are believed to be inherently afferent-receptor sensitive, can also be high-pressure tolerant. These two characteristics seem physiologically dichotomous to me.

So perhaps the 420e's maximum pressure parameter is meant to be capped as you say.

snoredog wrote:Flow Limitation is shown all over the patents put up seen as flattening, that is what the machine looks for to identify FL, looks at the sine wave changes from a normal rounded breath to flattening that of FL.

Well, you can see from the patent excerpt posted by ozij that more than simple flattening is discerned to score FL on the 420e. But for the sake of simplicity let's continue to call that handful of characteristic wave shape criteria flow-limitation "flattening".

snoredog wrote:it is what I've been saying all along, you guys have been bundling Flow limitation and Hypopnea as the same event all along

So as mentioned above the 420e runs a little multi-part criteria to decide if waveshape is "flattened". If it is "flattened" then a "flow limited cycle" is declared. That's waveshape, of course.

If that "flattened" wave shape occurs with little or no amplitude reduction, then the 420e simply calls it FL. If that "flattened" wave shape occurs with sufficient amplitude reduction, then the 420e calls it "H+FL" (that's not just "us guys" calling it a single event). If sufficient amplitude reduction occurs wiithout that "flattening" then the 420e simply calls it "H" (note they're not calling it "A").

So what's the significance of the 420e discerning between that "H" line and that "H+FL" line? Well, the "H+FL" that has "flattening" at the top does so because it is obstructive and needs static pressure to stent the airway. By contrast an "H" with no "flattening" at the top might be central, and should not receive an increase in pressure. So who treats a central hypopnea with yet more static pressure?

Anyway, that's the rationale behind what I think the 420e is doing...

snoredog wrote:Observe past reports and pressure used where HI show up, disable both IFL1 & 2, use a Minimum pressure lower than the A10 Command on Apnea setting or bump up that A10 setting higher than any Minimum set, then you should see it respond.

I agree that's a pretty good test. As you mentioned in another post there's not much past data to scrutinize with IFL1 and IFL2 turned off. I think we'll have to rely on new charts with that test in mind.

Snoredog wrote:

Adrian wrote:

Snoredog wrote:...
Have you tried raising the Maximum pressure ceiling from current 9.0 cm?

I would increase it to at least 15 cm even with those 2 centrals present.

But what I do see is AV or snoring continuing, so I would allow the machine to increase on up and take care of those, right now it looks like they are bumping up against your 9.0 cm ceiling. You are asleep when that snoring is happening so I wouldn't worry about it impacting your current therapy, but your snore index is over 101, bit too high.

Your Flow Limited cycles is close to 38% also too high in my opinion. Your target Normal cycle should be around 95%

Thanks for the suggestions. I have tried higher pressures, in the past, although my titration was 8. But any pressure I set, it appears that the 420E moves to more than 90% of the time to that maximum pressure and the AHI increases.
Anyway I'll try once again and will post here results in a few days.

Adrian

IF there was anyone that ever needed their IFL1 box unchecked it's you. And if those runs didn't settle down I'd uncheck IFL2 as well. You don't really have any apnea showing up in that report above, only a few Hypopnea, you have a couple CA's on line 2 BUT those are probably caused by all the FL runs and just because they show up on the reports don't forget the machine is NOT responding to those.

I would still increase the Maximum, if you uncheck that IFL1 box that should slow down or stop the runaway pressures.

Well I increased maximum to 13. Result is below:



As I expected the machine jumped to (almost) the maximum pressure, the trigger being a snore.
It seems very clear that the runs are not related to pressure. They happen both at 9 and at 13.
The flow limited cycle was at the same level (33%).

The only improvement was in the snore index that dropped from 36 to about 10, but the number of centrals increased.

I'm starting to believe in the shallow breath theory, but I'll also try unchecking IFL2 as well (but in theory it should not change much for me).

I hope you can give me some more advice.

Adrian

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CPAPopedia Keywords Contained In This Post (Click For Definition): 420E, Titration, AHI, Hypopnea