CPAPtalk.com

Last nights numbers below.
Here's a direct link if it's too big for your screen:
http://www.montfordhouse.com/cpap/s9/20 ... imetry.gif

Even though my AHI was 3.3, their durations seem, on the whole, shorter. The 02 line seems a little less eratic. I also feel a little better, I think, even with some aerophagia. I'm wondering if for my specific needs, I should be concentrating more on reducing the duration of the apneas and less on how many I'm experiencing. From previous night's graphs, it looks like a good portion of the beginning and end of my nights are sub-apneic events - just under the 10 second rule for apneas in breath after breath. The nights/naps where I have the long duration apneas seem worse for me. Anyway - food for thought. I had a couple OSA's this time - but I'm pretty sure it was from the effort of turning over - you know how you sometimes hold your breath when you're doing something strenuous. I think I was awake for the first. I know I was for the second - reaching to turn off the machine, eh?

On another interesting note: Heartbeat patency feedback - I found it!
Here's an example:


Last night's numbers:

Are you still using CPAP mode? I ask because I see your pressure varies ever so slightly, so you are either using CPAP mode and it isn't as constant as the machines usually report (which I would attribute to more accurate reporting on the S9), or you have APAP set with a minimum of 10.6 but don't make it over that too often.

DreamDiver wrote:filtering real data out of raw wave reports on what seems like a whim sounds not only professionally and scientifically malfeasant, but extremely difficult to attain, given the fluctuations in heart beat, the other rhythms you would have to screen out, and the fact that things like FOT show up at such high resolution. I'm not sure filtering just heartbeat from raw wave data is would be worth the effort in math-hours. Plus it's tampering with raw data. If anything, I would expect them to leave it as is to let others draw their own conclusions based on pure data rather than a patented process, just like seeing periodic breathing in the wave forms. Filtering seems improbable.

IMHO it's just a proprietary graphics report---not instrumentation for the scientific community or the Akashic records. They could have easily filtered COS...

DreamDiver wrote:On another interesting note: Heartbeat patency feedback - I found it!

But you found a NICE example of low-amplitude heart-rate frequency, showing COS is in the waveform. Very nice!

When past implementations relied on COS as an indicator of airway patency, that method yielded central-apnea sensitivity and specificity scores of 62% and 100% respectively. So that meant 38% of all central apneas would go undetected by the COS method. The 100% specificity score also meant that when COS happened to show up during an apnea, it was virtually certain to be central versus obstructive.

However, the 62% sensitivity and 100% specificity ratings were population based. The COS sensitivity rating, in particular, could vary drastically from one patient to the next. A patient almost never presenting COS during central apneas would find that airway patency detection method to be... shall we say malfeasant?

-SWS wrote:.. shall we say malfeasant?

Et tu Brute?

jmelby wrote:Are you still using CPAP mode? I ask because I see your pressure varies ever so slightly, so you are either using CPAP mode and it isn't as constant as the machines usually report (which I would attribute to more accurate reporting on the S9), or you have APAP set with a minimum of 10.6 but don't make it over that too often.

Correct - It's set to 10.6 Minimum. It doesn't get over that pressure because I'm experiencing central apneas with very few hypopneas. I'm considering going back to CPAP mode because APAP is useless for someone with predominantly central apneas.

unadog - The article is basically saying that some people end up with centrals just from treating obstructively? I'm wondering how many of them were actually misdiagnosed centrals to begin with. I also see that I've been mixing up Complex Sleep Disordered Breathing with Complex Sleep Apnea. Apparently there is also Mixed Apnea. I'm glad to learn there are distinctions, but I'm still a little fuzzy on the differences. I'd like to be able to more than cursorily skim the article, but my brain isn't back to that state yet. I'm better with abstracts. None of these terms is in the wiki yet, and there seems to be some difference of opinion as to exactly what is what when I skim threads in the forum. Wikipedia has some info on Complex Sleep Apnea and says it's equivalent to Mixed Apnea, but none on Complex Sleep Disordered Breathing.

Thank you for the article.

SWS - I wonder how COS compares to FOT in terms of reliability. I'd guess FOT is more sensitive, and certainly as specific. Who owns the patent to COS? I guess my interest in this might seem like an interest in using it as a method for central apnea detection. Clearly FOT is better. I just noticed I could hear it in my M-Series Pro, and wondered if - since the S9 is so quiet, I'd be able to at least detect something similar in the charts. So my interest is less about use, and more about 'Gee Whiz - there it is'.

ozij - I only partly get the reference to 'And you, Brutus?' from the Bard's play. I'm a way-fuzzy this morning. Could you help me make the leap for its reference here?

ozij wrote:

-SWS wrote:.. shall we say malfeasant?

Et tu Brute?

I was only trying to be humorous. Who would Julius Caesar be? The 420e?

I can't find that nice study you posted a while back, graphically showing COS distribution across the central-apnea population.

DreamDiver wrote:I wonder how COS compares to FOT in terms of reliability. I'd guess FOT is more sensitive, and certainly as specific. Who owns the patent to COS - Sandman?

My understanding is that Rapoport held the patent but sold or leased it to PB/Tyco/Sandman. Would love to find some specificity/sensitivity ratings for FOT.

I thought -SWS's "malfeasant " was a hint to your Latin in school. So I was wondering if -SWS too took latin in school...

Word Origin & History

malfeasance

malfeasant. (n.d.). Online Etymology Dictionary. Retrieved March 09, 2010, from Dictionary.com website: http://dictionary.reference.com/browse/malfeasant

1690s, from Fr. malfaisance "wrongdoing," from mal- "badly" (see mal-) + faisant, prp. of faire "to do," from L. facere "to do" (see factitious). Malfeasor "wrong-doer" is attested from early 14c. Related: Malfeasant.
Online Etymology Dictionary, © 2010 Douglas Harper

I should have written "Et tu Brute, took Latin in school too?" ... I though there were too many oo sounds in that....

ozij wrote:I was wondering if -SWS too took latin in school...

What a coincidence that you should ask...

As it turns out I DID experiment with Pig Latin for the better part of an afternoon during my high school years. ...But that's as far as my studies went.

unadog wrote:
<snip>

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2576323/

The appearance of treatment-emergent central apnea is well known and recently described. However the identification of central apnea appearing years after treatment of obstructive apnea is an older observation. Fletcher reported on a patient who four years earlier underwent curative tracheostomy for severe OSA and then had a 23-kg weight gain. He redeveloped hypersomnolence and when restudied, apneas of similar frequency, duration, and depth of desaturation reappeared but were now totally central in origin.

The mechanisms behind this phenomenon and CompSA are not well understood, but some comments can be offered. Presumably there must be dual causation that includes anatomic and physiologic vulnerability to OSA plus a central breathing control instability leading to chemo-reflex dysfunction. High loop gain is required.
 

Back to sleep. I have slept 2 hours + 3 hours so far... I'll try one last time .....  

Michael

Michael,

This para is another very memorable one - this whole thread has been remarkably stimulating & am betting that more of us have learned more about SDB & CompSA than many prior threads that attempted to deal with the topics.

>>
The mechanisms behind this phenomenon and CompSA are not well understood, but some comments can be offered. Presumably there must be dual causation that includes anatomic and physiologic vulnerability to OSA plus a central breathing control instability leading to chemo-reflex dysfunction. High loop gain is required. Loop gain is mathematically defined as the ratio of a corrective response (e.g., hyperpnea) to a disturbance (e.g., apnea). If corrective responses are greater than the disturbance (loop gain >1), then small disturbances can lead to self-sustaining oscillations. In the case of CompSA, we see a typical crescendo-decrescendo respiratory pattern indicative of a high loop gain state. In selected patients with OSA and higher loop gain, application of positive airway pressure in the form of proportional assist ventilation can produce such ventilatory instability leading to periodic breathing.4 Those patients with persistent CompSA like those with classic Cheyne-Stokes Respiration (CSR) can develop delays in the controller response during REM sleep. This explains the different behavior during NREM stage where disordered breathing events predominate and when in REM sleep, the events can disappear in patients with CSR or CompSA.5
<<

Thanks to all who have contributed & DD for triggering a fascinating journey through what can now be seen in ones own data. In this regard, it seems we cpappers have come a very long way in a very short time.

DSM

This is fascinating, isn't it? Going from the micro snapshots to the macro theories, while the doctors themselves are still debating what is going on?

We have access to an incredible level of detail. Now the task is to figure out what is meaningful, what is irrelevant, what is transitional - will go away as our brains adapt to the noise of CPAP, for example, and what really correlates with how we feel?

I have often thought that medical textbook explanations are so abstract - in some cases - as to really miss what is going on in the patient. Think of reading about "depression" or "schizophrenia" in college. No blood and guts, just boring text droning on .... Descriptions of "referred pain" in nerves, for example, also make you think it is not even an issue - not "real" pain - just a "misunderstanding" in the nerve system. But the pain is still real, even if it is perceived in a remote location - like a foot, rather than an impacted nerve in the back!

I think the same thing is going on here. The correlation between waveforms on a graph and how we feel the next day is pretty abstract. But for those of us struggling to feel better, bam, it gets our attention every day and won't let go! We have a certain experimental insight to what the squiggles and terms mean, and a lot of motivation to keep going!

It seems that there is a combination of brain learning (improved function), brain "habituation" (neutral maybe?) and brain dysfunction (impairment) going on here. I can see how the high gain could be prophylactic - extra breathing because the brain sees the patter "coming" - but could also be a product of brain degeneration - atrophy from overuse of a system that isn't getting adequate rest, for example. A product of ongoing, chronic fatigue/misuse day after day for years, and maybe recruitment of alternative brain areas to that behave in different ways "take up the slack."

They have been finding that type of dysfunction in the brains of people with chronic pain. Certain brain areas shrink at a certain, predictable rate in the presence of pain, so that the researchers can tell just looking at an fMRI how long someone has been in pain! (An argument for aggressive treatment of pain with analgesics - you are doing harm!)


patients with chronic pain caused by damage to the nervous system showed shrinks in the brain by as much as 11% - equivalent to the amount of gray matter that is lost in 10-20 years of normal aging.

The decrease in volume, in the prefrontal cortex and the thalamus of the brain, was related to the duration of pain.


They also see the same kind of deranged signal processing in people with fibromyalgia. I think, personally, that fragmented sleep architecture plays a large component in that altered function and systemic degradation! They also just releases a study on February 3 that showed chronic brain changes in people with severe OSA that has been untreated - maybe leading to centrals?

http://www.nlm.nih.gov/medlineplus/news ... 94873.html

WEDNESDAY, Feb. 3 (HealthDay News) -- People with severe obstructive sleep apnea have reduced concentrations of gray matter in multiple areas of the brain, new research shows.

Gray matter refers to the brain's cerebral cortex, where the majority of information processing takes place. These changes in brain structure may help explain the memory, cardiovascular and other problems experienced by people with obstructive sleep apnea (OSA), the study authors explained in a news release from the American Academy of Sleep Medicine.

The findings also show the importance of diagnosing and treating the condition, according to the South Korean researchers.

"Poor sleep quality and progressive brain damage induced by OSA could be responsible for poor memory, emotional problems, decreased cognitive functioning and increased cardiovascular disturbances,"


One real question for us then becomes: are the changes permanent? The consensus so far seems to be “maybe”, which will probably resolve to – some yes, some no.
While we have a privileged seat to see the granular effects of this, we have to be careful not to project our own individual experience to every problem (“I don’t think you have a broken leg, I think you have sleep apnea.”) Sort of the obverse of the doctors problem of drowning in statistics, with no sense for the reality of what the patient is experiencing (“Sure, you are tired, but so is everyone. It is just normal as you get older …”)

Cheers! Glad I can spin theories, and that I don’t have to justify grants on the micro level! I hope to get a prescription for an ASV after a sleep study next week, then I can start sticking the probes in my own brain!

Best,
Michael

First, I want to say thanks to all of the people who have helped enlighten me on this journey. I'm still pretty fuzzy about most of it, but it is beginning to sink in. Thank you.

Second, what I'm seeing from this is that having this machine may not be the best method for treating centrals, even if it is aces at detecting them. I'm loath to consider giving up a machine that can give me this much data. I have half a mind to write Resmed and beg them for a hybrid S9 that will give me SV treatment with S9 recording granularity. I am not sure I'll be able to afford yet another machine, especially one that is considerably more expensive. One consideration is this: will having an SV machine give me that much better results, or am I always going to have to live with a certain amount of headache and central apnea?

The kicker is that aerophagia will always wake me up at any pressure over 11, so higher pressures won't really work for me.

I'd be grateful for some feedback from forum members who have predominantly centrals, using SV units.

I understand these are the options available:
Respironics BiPAP Auto SV
S8 VPAP Auto 25 BiLevel Machine
Are there other machines that might suit my particular needs better?

I think I need to see a sleep doc, and I've been fortunate enough to receive some suggestions by fellow forum members living in the Atlanta, GA area.
Are there any suggestions as to what I should ask, be prepared for, etc., when talking to someone about Complex Sleep Apnea, etc.?

My first impulse is to go in armed with graphs and data.

This is turning out to be one interesting month.
Again - thank you, DSM, SWS, ozij, unadog, jmelby, DreamOn, snnnark, Arizona-Willie, coreyg, Uncle_Bob, preemiern.. -- everyone.

DreamDiver wrote:First, I want to say thanks to all of the people who have helped enlighten me on this journey. I'm still pretty fuzzy about most of it, but it is beginning to sink in. Thank you.

Second, what I'm seeing from this is that having this machine may not be the best method for treating centrals, even if it is aces at detecting them. I'm loath to consider giving up a machine that can give me this much data. I have half a mind to write Resmed and beg them for a hybrid S9 that will give me SV treatment with S9 recording granularity. I am not sure I'll be able to afford yet another machine, especially one that is considerably more expensive. One consideration is this: will having an SV machine give me that much better results, or am I always going to have to live with a certain amount of headache and central apnea?

The kicker is that aerophagia will always wake me up at any pressure over 11, so higher pressures won't really work for me.

I'd be grateful for some feedback from forum members who have predominantly centrals, using SV units.

I understand these are the options available:
Respironics BiPAP Auto SV
S8 VPAP Auto 25 BiLevel Machine
Are there other machines that might suit my particular needs better?

I think I need to see a sleep doc, and I've been fortunate enough to receive some suggestions by fellow forum members living in the Atlanta, GA area.
Are there any suggestions as to what I should ask, be prepared for, etc., when talking to someone about Complex Sleep Apnea, etc.?

My first impulse is to go in armed with graphs and data.

This is turning out to be one interesting month.
Again - thank you, DSM, SWS, ozij, unadog, jmelby, DreamOn, snnnark, Arizona-Willie, coreyg, Uncle_Bob, preemiern.. -- everyone.

DreamDiver

My belief is that unless Resmed do a serious redesign of the Vpap Adapt SV, it will not be the best choice to become another S9 model.

The problems it would bring (without significant redesign) is that the mask management would be a nightmare for too many people. The machine is very leak intolerant & its very tight breathing control means it is very prone to breaching mask seals. The Bipap Auto SV is a better candidate (itself with some changes such as adding a decoupled eepap that auto titrates epap without pushing Ipap & SV pressure ranges up & down).

The Vpap Adapt SV is very good at what it was designed to do but when it goes askew (due to the regular mask issues one has) it does more harm than good to ones sleep. The Bipap Auto SV with its Average Peak Flow tracking & less dominant pressure changes still does a good SV job but is far easier to manage over time. When it goes askew it does far less disruption to sleep.

So if there were to be SV capability added to an S9, it would (IMHO) need the following modifications ...

- Remove the proximal mask pressure sensing line (thus requiring a reworking of the SV control algorithm)
- Extend the 3 min tracking window to at least 4+ mins & look more at averages rather than a tight & specific tidal flow target
- Reclassify the purpose of the machine as the mods I am suggesting would detune the machine somewhat (i.e. the original machine would remain best choice for CHF & CSR patients)

The blower in the S9 is totally capable of providing SV support.

Cheers

DSM

-2 put 'in' in front of the word tolerant.
-

DreamDiver wrote:One consideration is this: will having an SV machine give me that much better results, or am I always going to have to live with a certain amount of headache and central apnea?

I don't think anyone or anything short of an ASV trial can answer that.

DreamDiver, do I understand correctly that your central dysregulation problem is largely manifest immediately after bathroom breaks?

DreamDiver wrote: will having an SV machine give me that much better results, or am I always going to have to live with a certain amount of headache and central apnea?

This is probably the best summary I have seen. It is from the powerpoint slides at the first link I posted this morning:



ADAPTIVE PRESSURE SUPPORT SERVO-VENTILATION
• Figure 2. Box plots of effect of treatment on central apnea
index. Horizontal bar: median; thick vertical line: interquartile
range; circles: outliers; thin bar: range excluding outliers.
Also shown are statistical significance of comparisons
between control and each of the four treatments, and
between ASV and the other four conditions.


I am not sure of the date on the data? It seems to indicate on the slide that they were from 2001, which is way too early! But I have seen the numbers in table form elsewhere - think maybe there were from Shahrokh Javaheri, in November, 2009?


Going through the hurdles to get approvaed for an ASV is another question! My centrals are from medication, so it is a different "sub-category" I believe. It won't just "go away." Approval is easier there I think.

The steps outlined in this BCBS Policy Manual are quite daunting! Section F, page 4:
http://www.bcbsnc.com/assets/services/p ... evices.pdf

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

F. Complex Sleep Apnea:

“Complex Sleep Apnea” as used in this policy is defined as a clinical syndrome where central apneas develop during pressure titrations in the sleep lab in patients who have demonstrated obstructive sleep apnea either at initial p olysomnography or during an unattended (unsupervised) home sleep study.

Coverage of bilevel PAP device with a backup rate or an adaptive servo-ventilation (ASV) device may beconsidered medically necessary in patients with Complex Sleep Apnea syndrome when the central apneas
have failed to respond to:

1. Reduction in the administered CPAP or bilevel pressures in the sleep lab (’down titration’); and

2. Acclimation/desensitization to pressure therapy by a trial of auto bilevel PAP in the home setting with appropriate, gradual acclimation measures for a period of at least four weeks, followed by a bilevel PAP titration in the sleep lab for determination of definitive treatment pressures; and

3. Evaluation and treatment of underlying medical conditions or etiologies (e.g., thyroid disease, opiateuse, renal failure, etc.);

and when the back-up rate or ASV device has been shown to be effective in the sleep lab.

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

Thinking out loud ...
Perhaps Resmed can add a new feature to another model of S9 called PBC that can be activated & deactivated & perhaps have 3 or so levels of drive.
The name meaning Periodic Breathing Control feature. Sort of like the EPR feature which was a bilevel functionality disguised as an add on feature.

ASV machines are just going to remain far too hard to get approval through both Drs and Health insurance. At least until their cost drops a great deal..

DSM

-2 qualified meaning of approval in last line