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EERS Experiment Data (sherwoga)
RE: EERS Experiment Data (sherwoga)
Regarding mask, at least part of the mask if not most of it would be flushed out when not using EERS, this is due to flow dynamics. During normal operation the air being supplied by cpap machine must flow into your mask, do a 180 degree change of direction inside the mask and then flood out the vents if I had to guess at least 75% of the mask volume is likely being purged of carbon dioxide during normal use. I could be wrong but I believe the studies I looked at talked about taking mask volume into consideration and your 6 inch version is probably in the 100-150 range and likely all you need for effective EERS (the effects on centrals should tell you if it is working).

Regarding the breathing like I said I don't know what to call it but it isn't isn't flow limitation, tremoring diaphragm was just a shot in the dark based on what I was seeing. Flow limitations cause a reduction in flow rate, they do not change flow direction and during those periods your breath direction is fluctuating throughout a normal breathing cycle. This isn't like rem where you are just getting irregular shaped breaths, there is an obvious repeatable breath waveform present being disturbed by some other action. Try to replicate that breathing in your head (or wearing mask if you want to see what it looks like on OSCAR), I don't even think I could do it.

How often does that kind of breathing occur? I'd be curious to see what an oximeter or video recording might tell you about the situation.
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RE: EERS Experiment Data (sherwoga)
(02-04-2020, 02:18 PM)Geer1 Wrote: Regarding mask, at least part of the mask if not most of it would be flushed out when not using EERS, this is due to flow dynamics. During normal operation the air being supplied by cpap machine must flow into your mask, do a 180 degree change of direction inside the mask and then flood out the vents if I had to guess at least 75% of the mask volume is likely being purged of carbon dioxide during normal use. I could be wrong but I believe the studies I looked at talked about taking mask volume into consideration and your 6 inch version is probably in the 100-150 range and likely all you need for effective EERS (the effects on centrals should tell you if it is working).

Regarding the breathing like I said I don't know what to call it but it isn't isn't flow limitation, tremoring diaphragm was just a shot in the dark based on what I was seeing. Flow limitations cause a reduction in flow rate, they do not change flow direction and during those periods your breath direction is fluctuating throughout a normal breathing cycle. This isn't like rem where you are just getting irregular shaped breaths, there is an obvious repeatable breath waveform present being disturbed by some other action. Try to replicate that breathing in your head (or wearing mask if you want to see what it looks like on OSCAR), I don't even think I could do it.

How often does that kind of breathing occur? I'd be curious to see what an oximeter or video recording might tell you about the situation.


I've been wearing an oximeter for better than a year and a half.  I wear it mostly because it monitors heart rate and tells me if I have had an atrial fibrillation event during the night.  My A-Fib is and has been almost 100% controlled with prescription drugs.  I've had no events in well over a year.  But as designed the oximeter's primary purpose is to monitor peripheral blood O2 saturation.  So I get a picture of that information, too.  It can not be interfaced with my CPAP or OSCAR software.  But my O2 levels remain almost universally between 90 and about 97%, with minimal drops of >4%.  It is an O2Vibe.  While I can't make the computer analyze for even small losses of oxygen during period of apparent rapid respiration (as indicated by OSCAR), I've tried looking for this behavior manually.  I never see anything that I can call a correlation.  

Regarding the flow pattern, it is much rarer that it doesn't occur sometime during the night than that is does. It happens most nights.
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RE: EERS Experiment Data (sherwoga)
So one thing that this reminded me of but in a much more exagerated form was what I just found out to be called cardiogenic oscillations. It is when your heart rate transfers into your flow rate data and it is visible on many if not most peoples data at some points although it is usually just little barely noticeable bumps only visible during the pause between inhalation and exhalation.

Assuming it is cardiogenic oscillations it would be a heart rate around 75 bpm which is probably about right. The strange part about this is why it is causing such a large affect and why it is transferring into your inhalation and exhalation periods.

An article kind of discussing this phenomenon.

https://www.semanticscholar.org/paper/Ca...767c655bcf
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RE: EERS Experiment Data (sherwoga)
Also I noticed this seems to screw with your pressure support a bit (every time your flow rate crosses 0 it starts or stops EPR/PS), hard to tell how bad it is affecting things though.

It got me thinking that one thing that might help with the Vauto is Ticontrol and possibly trigger sensitivity. I am still not sure about that and maybe it would just be more of a mess if it gets triggered too soon but it is another level of control you will have with the bilevel that would be worth looking into.
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RE: EERS Experiment Data (sherwoga)
(02-04-2020, 04:56 PM)Geer1 Wrote: So one thing that this reminded me of but in a much more exagerated form was what I just found out to be called cardiogenic oscillations. It is when your heart rate transfers into your flow rate data and it is visible on many if not most peoples data at some points although it is usually just little barely noticeable bumps only visible during the pause between inhalation and exhalation.

Assuming it is cardiogenic oscillations it would be a heart rate around 75 bpm which is probably about right. The strange part about this is why it is causing such a large affect and why it is transferring into your inhalation and exhalation periods.

An article kind of discussing this phenomenon.

https://www.semanticscholar.org/paper/Ca...767c655bcf

Thank you for the article reference.  I've read it entirely twice.  At a bare minimum it makes the case that what I am seeing is indeed cardiogenic oscillations; however, the researchers were attempting to use the presence of the oscillations on the air flow trace to generate an algorithm in a CPAP machine they were trying to design that would detect and classify an apnea as central.  I see the pattern during normal respiration when there is no indication of an event of any type.  The article is 20 years old and probably now suffers from the lack of technological advances that have been made in the design of CPAP machines during that 20 years.  Indeed, the paper may well have contributed either positively or negatively (i.e. showed the design engineers what direction not to go) to the evolution of those machines.  The paper is not directly applicable to what I am seeing, but it is fantastic to finally see in print my flow pattern and to be able to identify it.  Mechanism for transmitting the heart rate into the air flow trace might be a simple change in the lung volume in sync with the changing heart volume as the latter does it's thing (contracts and expands).

The paper appears to make no attempt to comment on the consequences, positive or negative, of the presence of cardiogenic oscillations.  Authors do comment that, even by 1999, patients showing these oscillations during normal respiration had been observed. So I remain ignorant whether my flow patterns are bad or of no consequence.  

Reviewing my initial posts to this board and my other records I can categorize my data as follows:

Oct 19 to Nov 5, 2019.  Data was all obtained with SD Flash Card in my CPAP, but no changes were made to my settings.  During this period I operated at settings that had been prescribed on or before Oct 20 of 2018.  I call thess my Rx (prescription) settings .  During this time I was learning how to use OSCAR software and stumbling around quite a bit as I did so, but those stumblings did not cause me to make any changes to my settings.  Runs in this period do show cardiogenic oscillations, but I would say they are not as exaggerated.  If I didn't know to look for them I might miss them.  My AHIs were much higher, too, with the lion's portion being attributable to CAs.  

Nov 6 to ~ Nov 21, 2019.  I started making changes to settings.  First and most significant was to lower my EPR from 3 to 1 in response to a Apnea Board recommendation.  At the same time it was recommended that I begin to lower my maximum pressure incrementally, which I did through this period.  There was no EERS involved through out this time because I didn't receive the parts to make an EERS until Nov 21.  Again, runs during this period clearly show cardiogenic oscillations and they are getting more defined.  OAs and CAs are lower in general (I believe in response to the settings changes) and this lowering of event seems to have also been coincident with the amplification of the oscillations in the air flow signal, that is they are easier to see.  

~ Nov 22 to Nov 28.  I was working on putting the EERS together and I made my share of stupid mistakes in that project.  But I eventually got it right.  During this brief period I was testing out my prototypes (even the completely failed ones) and my records are inadequate to comment on the state of the cardiogenic oscillations.  

Nov 29 til now with some interruptions.  I have been conducting my designed experiment in about 3 stages.  1)  Acquisition of the original 16 runs required to get 4 replicates as each corner of the design.  2) Acquisition of an additional 16 runs required to test for curvature.  3) Acquisition of 8 runs, four each at two treatment combinations not previously tested, but that were identified as potentially optimal based on the results of analysis of the data obtained in the first two stages.  I will have all of this data by Friday morning.  The cardiogenic oscillations have been present throughout this effort, even in runs when the treatment combinations called for NO EERS.  

My conclusion is that the EERS is not a cause of the oscillations, or even of amplification of the signal.  

Going forward from Feb 7, I will be using the Vauto.  More comments later.
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RE: EERS Experiment Data (sherwoga)
(02-04-2020, 05:02 PM)Geer1 Wrote: Also I noticed this seems to screw with your pressure support a bit (every time your flow rate crosses 0 it starts or stops EPR/PS), hard to tell how bad it is affecting things though.

It got me thinking that one thing that might help with the Vauto is Ticontrol and possibly trigger sensitivity. I am still not sure about that and maybe it would just be more of a mess if it gets triggered too soon but it is another level of control you will have with the bilevel that would be worth looking into.

I've reread the manual and I still don't understand triggering, cycling, or TiControl settings in the slightest.  I have a long way to go on that and it may have to involve my pulmonologist.  But he's not even on board with the Vauto yet.  I don't even know how to approach him but know I need to.  

I also don't know how to comment on your observations concerning the mask pressure, but I see what you see.  Higher PS will hopefully eliminate or elucidate this effect.  

In the mean time, Geer1, and I suspect you will have a visceral reaction to this, you are in actuality setting me up for another designed experiment.  Please, don't waste your time trying to school me on the way to conduct research.  I hold a PhD in chemistry and have 35 years of conducting research under my belt, even if I have many limitations.  You'll be wasting your time and mine.  On the other hand, I can see your heart is in the right place and I really appreciate your persistence in sharing your knowledge, thoughts, and even wisdom.  I'm glad we've kept this dialog going and hope we can continue to do so.
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RE: EERS Experiment Data (sherwoga)
This recent thread covers those settings.
Caveats: I'm just a patient, with no medical training.
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RE: EERS Experiment Data (sherwoga)
Regarding cardiogenic oscillations, there is no consequence to normal oscillations, as far as I am concerned this is a phenomenon that can be seen when the body pauses and relaxes after an exhalation. These oscillations can be seen on most peoples OSCAR data and I don't think they indicate central apnea as the study was kind of theorizing. One way to visualize them(at least in my case) is to lay down, exhale and relax, if like me you will be able to see your chest/belly moving to your heart beat. I agree with you that this shows up on flow data because of heart contraction/expansion affecting lung size creating minor flow changes the machine picks up. 

What doesn't seem normal to me is why your heart beats have such an amplified affect on this and why they remain present during active inhalation/exhalation. Here is an example of my cardiogenic oscillations which is on par with what I have seen in other users OSCAR data, as you can see it is only visible during relaxation after exhalation and this is the same as was commented on in the study. Your breathing during these periods is similar but significantly amplified and still remains present when body is actively breathing.

   

As for research, I can tell you know how to do it. I disagree with a couple points on the setup/target of the test but  hey that is what sets a scientist apart from an engineer. Scientist like to to take into account all variables and perform rigorous analysis before drawing any conclusions whereas we engineers are expected to make conclusions on limited data in a short amount of time so focus more on eliminating any and all variables that we believe to be inconsequential. We sometimes miss things by making wrong assumptions so I am all for you performing whatever tests you think you need to do, I am just providing a different point of view on things and seeing if you have thought through some of these things that I am curious about. I have actually been following your thread for a while and was hoping to see some clear conclusions that might be applicable for my grandfather but as time has gone on I started questioning if you were on the right path and figured I would give my two cents, hopefully I haven't brushed you the wrong way in doing so.

Triggering and cycling sensitivity controls when the machine will initiate IPAP or EPAP, the higher the sensitivity the faster it will react and either increase or decrease pressure. I don't know exactly how it works but I believe it does this either by changing the flow rate at which IPAP/EPAP is triggered (ie perhaps high trigger sensitivity starts building pressure soon as flow rate passes 0 whereas lower sensitivity starts it at flow rate of 3, these are random numbers just to convey point). I thought maybe it increased the speed at which pressure was raised but that appears to be another variable that is available in S mode (rise time). Regardless of how exactly it works this sensitivity setting has an effect on people and some think it helps while others feel like it is forcing them to breath to soon. 

TiControl has two variables TiMin and TiMax and it is simply a range of allowable inhalation time that Vauto imposes. If your body only takes a short little breath of air the autoset would stop supplying increased pressure as soon as the flow rate passes 0 but with the vauto it will continue to supply/increase pressure until TiMin is reached in the hopes you may take in more air. TiMax sets a max time for inhalation in order to try and keep the machine in rhythm with your body by lowering pressure to help initiate expiration. 

Now what I am not sure about is how these settings are going to affect you. A high trigger sensitivity and TiMin could force air on you(and continue to force air for length of TiMin) before you are ready for it if the severe cardiogenic like oscillations trigger the inhalation process in the machine. If that is the case you may find lowering the sensitivity helps. Conversely the combination of these settings once set right may keep some of these oscillations in check by not reducing pressure after the first oscillation and helping you with the inhalation process by continuing to increase pressure. I am not really sure what the ideal settings will be in your case I just see these settings on the Vauto as potentially being either helpful or a hindrance and something to be aware of.

Your current Autoset does not have this functionality and that is why your pressure can't make its mind up on what to do when your breathing is out of whack. I could see these settings having more of an effect on that breathing then a higher level of pressure support, I just can't wrap my head around whether or not it will be a positive or negative effect though. 

As for the Pulmonologist, rather then dropping the bilevel bomb on him to start I would probably question him about this breathing and any other things you are wondering about then discuss the EERS if you haven't already done so. That way you can gauge his feelings and then ask his thoughts on things and bilevel rather than getting a skewed reaction because he is annoyed you have started using bilevel (and possibly EERS).
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RE: EERS Experiment Data (sherwoga)
(02-05-2020, 05:18 PM)Geer1 Wrote: Regarding cardiogenic oscillations, there is no consequence to normal oscillations, as far as I am concerned this is a phenomenon that can be seen when the body pauses and relaxes after an exhalation. These oscillations can be seen on most peoples OSCAR data and I don't think they indicate central apnea as the study was kind of theorizing. One way to visualize them(at least in my case) is to lay down, exhale and relax, if like me you will be able to see your chest/belly moving to your heart beat. I agree with you that this shows up on flow data because of heart contraction/expansion affecting lung size creating minor flow changes the machine picks up. 

What doesn't seem normal to me is why your heart beats have such an amplified affect on this and why they remain present during active inhalation/exhalation. Here is an example of my cardiogenic oscillations which is on par with what I have seen in other users OSCAR data, as you can see it is only visible during relaxation after exhalation and this is the same as was commented on in the study. Your breathing during these periods is similar but significantly amplified and still remains present when body is actively breathing.

...

Triggering and cycling sensitivity controls when the machine will initiate IPAP or EPAP, the higher the sensitivity the faster it will react and either increase or decrease pressure. I don't know exactly how it works but I believe it does this either by changing the flow rate at which IPAP/EPAP is triggered (ie perhaps high trigger sensitivity starts building pressure soon as flow rate passes 0 whereas lower sensitivity starts it at flow rate of 3, these are random numbers just to convey point). I thought maybe it increased the speed at which pressure was raised but that appears to be another variable that is available in S mode (rise time). Regardless of how exactly it works this sensitivity setting has an effect on people and some think it helps while others feel like it is forcing them to breath to soon. 
...

Now what I am not sure about is how these settings are going to affect you. A high trigger sensitivity and TiMin could force air on you(and continue to force air for length of TiMin) before you are ready for it if the severe cardiogenic like oscillations trigger the inhalation process in the machine. If that is the case you may find lowering the sensitivity helps. Conversely the combination of these settings once set right may keep some of these oscillations in check by not reducing pressure after the first oscillation and helping you with the inhalation process by continuing to increase pressure. I am not really sure what the ideal settings will be in your case I just see these settings on the Vauto as potentially being either helpful or a hindrance and something to be aware of.

...
I do appreciate the ongoing dialog.  Writing, although I'm pretty verbose, always helps me develop and focus my thinking. 

You supplied your flow patterns to illustrate cardiogenic oscillations superimposed but not nearly so obvious as in my previously shared flow pattern.  I've used graphic cut and paste software (SnagIt from Techsmith) to combine your flow patterns with another example of mine.  This time I'm sharing an example where the cardiogenic oscillations are not as obvious. It represents about the most "normal" pattern I ever see.  Admittedly, differences in computer displays and the machinations I've used to create the comparison may well have introduced at least some distortion, but I hope my efforts to make the axes similar have created only very minimal distortions.  

   

I note in my patterns three very significant differences relative to your patterns (calling yours "normal" or at least more nearly normal). 

  1. Starting at the most negative point on your pattern for each breath, the signal rises pretty rapidly to a plateau region at the zero line.  My signal rises much more slowly from the minimum toward the zero line.  
  2. The plateau region in your pattern occupies roughly between 30 and 50 % of the total breath cycle (that being a very crude visual judgement).  My plateau doesn't really seem to exist at all, but the presence of the oscillation superimposed on my signal makes that judgement call more difficult to make.  I think I can safely claim that any plateau that is there occupies a much smaller % of my total breath cycle. Does this plateau correspond to a complete cessation of respiration effort and amount to a rest period in your pattern? And if so is it of note that I appear to be missing out on that rest in my breath cycle?    
  3. Once your signal starts to rise above the zero line you get a peak that is very rounded on top with a relatively narrow width.  My corresponding peak is flat topped and appears to be wider.  

Does this examination inspire any additional thoughts regarding my breath cycle?  regarding the Trigger and Cycle settings?
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RE: EERS Experiment Data (sherwoga)
Flow rate waveform depends on sleep stage as well as likely a number of other factors, that was just one example of mine during a period showing more oscillations. I think it might be slow wave sleep as slow wave sleep has lower ventilation requirements and has really nice looking breathing. Here is another one of mine more similar to yours, taken from the same night if I had to guess probably N2 sleep. 

   

When your breathing is like that I don't foresee any issues. It is specifically the periods of time when your breathing looks like the waveform shown in the following post that I could see trigger sensitivity and Ticontrol either helping or causing havoc. It is this waveform specifically that I do not believe is normal and when you compare it to your more normal breathing just posted you can probably see why I say it seems like it might be due to an amplified cardiogenic oscillation type situation but if so I don't get how or why. 

http://www.apneaboard.com/forums/Thread-...#pid332359

Edit: The flatter peaks on your breathing could be indicating flow limitation. That is closer to flow limitation then what this odd looking breathing is.
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