A chart showing OSA effects - Part 1

I'm not sure Kenny if you're getting a headache from the technical issues, or from the obvious interpersonal clashes (it would be both for me). The interpersonal issues despite looming large, really should not be at the focus.
It does happen to us every now and then, the attempts to understand a professional's statement(s) suddenly veers into arguments about a member's point of view as though this were a debating club in which people have to prove a point of view. That veering off can indeed be very confusing.

Concerning OSA:

• About a week ago, dsm decided to share charts from a presentation titled The Ups and Downs of Bi Bi-level Pressure Therapy in Sleep disordered breathing, given by Dr. Shahid M. Ahsan MD a few months ago.
  Muffy kindly supplied the link to the full presentation, which appears in : http://www.in-isrc.org/docs/081013.Upsa ... PinSDB.pdf
  dsm criticised Dr. Ahsan for getting his definitions of Mixed apnea and CompSAS back to front.
  I thought this statement was incorrect, and furthermore, might make readers distrust a very informative presentation. So I took issue with dsm's criticism.
  After some discussion, some of it quite heated, it turned out that "Mixed apnea" was appearing on this thread in two disparate meanings:
  • As a description of an event scored during a PSG (Dr. Ahasan's usage on slide 4)
  • As a description of a condition, a usage which seem to have been more prevalent before CompSAS, or Complex SDB became the prevailing terns to describe that condition.

Dr. Ahsan in slide 4 of his presentation clearly refers to an event and the ways to score it.

The condition (or diagnostic entity) called "mixed apnea" isn't a subject of the presentation --

That said, knowing the medical dictionary description of the condition will help me understand the term when it is used as a diagnostic entity. It will also be very helpful for me to know that CompSAS and Complex SDB are two newer terms used to describe that same condition.

IMO, the important issue on this thread is the existence of a detailed informative, reliable presentation, available on the internet for all of us to learn from.

O.

Well, I personally don't care for either personality clashes or "word twisting". I have been trying to avoid both of those in this thread...

But the subject matter that's up for discussion is worth clarifying toward our common understanding IMHO. The fact that dsm corrected Dr. Ahsan is entirely unimportant to me at an intangible or interpersonal level. The fact that I think that correction might have been informationally wrong is specifically what I am interested in discussing. I have very specifically been confused about understanding the CONTENT of the information that dsm proposes as a correction to what Dr. Ahsan presented.

Toward trying to better understand the content of dsm's proposed correction, I have offered that the term "mixed apnea" often entails these two usages:
1) an individual clinical event that is comprised of exactly one apnea of mixed characteristics, or
2) a condition entailing an overall mixture of obstructive and central event types---and for some patients individual mixed apneas might even be thrown into the overall mix as well.

So we can see above, that a patient might actually have an overall condition referred to as "mixed apnea" while never having a single clinical event also correctly referred to as a "mixed apnea". They might have ONLY obstructive apneas and central apneas, while being categorized with the condition known as "mixed apnea".

I personally don't care to "kill" dsm's point of view. But I think if dsm is going to explain to us that Dr. Ahsan has medical terminology back-to-front, then we have a right to understand EXACTLY what it is that dsm is trying to tell us. I am not trying to twist dsm's words. Rather, I am trying to understand EXACTLY what it is that he is telling us about "mixed apneas"---with no attached personal agendas of any kind (contrary to earlier accusations). It's only after rereading this thread today that I THINK I might understand what dsm has been telling us about "mixed apneas" based on these two sets of comments:

dsm wrote:I didn't think what I said was 'clearly' a single event situation ?
... Further "an obstruction that can become a central" doesn't 'clearly' say a single-event ?

viewtopic.php?f=1&t=48860&start=45#p449735

dsm wrote:I never mentioned a string of events...
I saw a situation where an event pair was occurring.

viewtopic.php?f=1&t=48860&start=45#p449755

So I could be VERY wrong, but I think dsm is saying that "mixed apnea" as a clinical event is a pair of interrelated apneas---but specifically either: 1) an obstructive apnea followed by a central apnea, or 2) a central apnea followed by an obstructive apnea.

However, I have never seen a "mixed apnea" or the condition known as "mixed apnea" defined that way---as a pair. To the best of my knowledge, the term "mixed apnea" refers to either a single apnea of mixed characteristics or an SDB condition with an overall mixture of event types.

And IMHO there's absolutely nothing sinister about trying to nail those important definitions down on an apnea-related message board of all places.

OK, I'm pretty good on "Part 1".

Let's get a look at "Part 2".

Muffy

Muffy wrote:OK, I'm pretty good on "Part 1".

Let's get a look at "Part 2".

If you can help get us straightened out on either "mixed apnea" usage, that would help immensely IMHO: 1) the term "mixed apnea" as a clinical event, versus 2) the term "mixed apnea" as an overall SDB condition...

It's clearly a "mixed" topic that we need to understand better.

Seriously, it's just so much easier to just block dsm's posts. It's simply too frustrating.

Everybody else in the thread is exactly right. A mixed apnea (a SINGLE event) starts out central, but when effort resumes, becomes obstructive. It is far more easy to conceptualize this by assuming obstruction was always present (see the thread where we discussed how many central apneas on ambient pressure have, in fact, a closed airway) but only became apparent with patient effort.

Collections of central apneas and obstructive apneas in a single patient study might be labelled "mixed" only because it is a convenient adjective-- however, given this discussion, it's pretty obvious that that should be avoided like the plague. The disease process therefore, would probably be termed be CompSAS if that scenario occurred during titration, and something like "obstructive sleep apnea with underlying central component" if it occurred during diagnostic.

Anyway, nomenclature of SDB is determined by the International Classification of Sleep Disorders, and last time I looked, "mixed apnea" as a disease state was not there.

Muffy

And BTW, before you ask:

http://www.ncbi.nlm.nih.gov/pubmed/1885 ... &linkpos=1

Muffy

Muffy wrote:Collections of central apneas and obstructive apneas in a single patient study might be labelled "mixed" only because it is a convenient adjective

That's the impression I was under: not a formal diagnosis, but a convenient usage for the intermixed condition itself---and falling out of favor in that context.

Muffy wrote:-- however, given this discussion, it's pretty obvious that that should be avoided like the plague.

Boy, do I agree with that.

Muffy wrote: The disease process therefore, would probably be termed be CompSAS if that scenario occurred during titration, and something like "obstructive sleep apnea with underlying central component" if it occurred during diagnostic.

Anyway, nomenclature of SDB is determined by the International Classification of Sleep Disorders, and last time I looked, "mixed apnea" as a disease state was not there.

Once again, thank you!

And thanks to everyone who contributed clarifying information to this thread regardless of point of view.

dsm wrote:
I keep asking myself what is 'a mixture of both OSA and CSA' or 'a mixture of OSA' as taken from the presentation and in relation to an OSA event that converts CSA - I just can't see a clear explanation.

CompSA is defined repeatedly as OSA that converts to CSA (see the chart you posted). Where does 'mixture' come into it ?. The OSA doesn't mix or come as a mixture (Mixed Apnea does depending on how you want to define mixture) ?. CompSA 'includes' OSA (that converts to CSA) and CSA but where is the 'mix' / 'mixture' ?. It seems to me it is a stretch of the use of English to say it mixes ?.

Cheers

DSM

#2 - PS I looked at the original Mayo Clinic definition & they don't use the word mixture anywhere
http://www.mayoclinic.org/news2006-rst/3608.html
Extract "The newly discovered type, complex sleep apnea, is a combination of both obstructive and central sleep apneas. " - no mention of mix or mixture.

That was an interesting presentation, but why are you so concerned with the word "mixture" DSM?

Can I hypothesize as to where the word "MIXTURE" came from? Dr. Ahsan indicates by his footnote that he is presenting information originally from Morganthaler et. al. In my experience, when writing papers, preparing presentations etc, it is of the utmost importance not to plagiarize other people's work, so we have to summarize and keep to the closest meaning without using the original author's exact words. There are only so many synonyms for the word combine, but I would guess one of the most common is mix. Could he be summarizing?

My next guess would be that Morganthaler et. al actually used the word mix or mixture. Guess what Morganthaler et. al. Hypothesized on page 1203 of SLEEP, Vol. 29, No. 9, 2006? (I added the bold) :

We hypothesized that, since the differentiating respiratory
feature in CompSAS was the development of central apneas or
Cheyne Stokes pattern mixed in with or superseding the obstructive
pattern, the clinical and polysomnography (PSG) patterns
seen in patients with this disorder should more nearly match those
in patients with the CSA pattern or Cheyne-Stokes breathing syndrome
(which for simplicity we together call central sleep apnea,
or CSA) than those with the OSAHS. We undertook to determine
the prevalence of the CompSAS in a sleep disorders center. Next,
we sought to determine the clinical and PSG features of patients
with CompSAS and compare or contrast them with those of patients
with OSAHS and CSA.

Muffy wrote:And BTW, before you ask:

http://www.ncbi.nlm.nih.gov/pubmed/1885 ... &linkpos=1

Muffy

Not to be a troublemaker Muffy, but there are two articles in that journal printed right next to each other in the Pro/Con Debate section. The other one is called Complex Sleep Apnea: It Really Is a Disease by Peter C. Gay, M.D.page 403-405. Journal of Clinical Sleep Medicine, Vol. 4, No. 5, 2008. I don't think they've decided if it is or isn't yet.

I would also like to see part two of Dr Ashan's presentation.

r

Rebecca R wrote: but there are two articles in that journal printed right next to each other in the Pro/Con Debate section. The other one is called Complex Sleep Apnea: It Really Is a Disease by Peter C. Gay, M.D.page 403-405. Journal of Clinical Sleep Medicine, Vol. 4, No. 5, 2008. I don't think they've decided if it is or isn't yet.

I would also like to see part two.

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

That kind of back-and-forth debating via published white papers---entailing a highly rational exchange of ideas--- are a tradition and an extremely important part of science/medicine IMHO. That same kind of highly rational (well-intended) "peer debate" occurs for UARS and a host of other medical and scientific topics to this day.
viewtopic.php?f=1&t=40009&p=352405#p352405

I'm not sure if I love those more than I respect them... or if I respect them more than I love them.


This well-known example of rational contention by John P. A. Ioannidis questions scientific research in its entirety:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1182327/

Thank you, ozij, -SWS, Muffy, Rebecca R, and JohnBFisher for providing clarifying information, expressed in your very well thought-out posts.

Thank you very much Muffy for posting a direct link (early in this thread, on page 2) to the presentation.

I appreciated dsm's bringing Dr. Ahsan's good presentation to the forum's attention in the post that started this most interesting thread.

Rebecca R wrote:Not to be a troublemaker Muffy, but there are two articles in that journal printed right next to each other in the Pro/Con Debate section. The other one is called Complex Sleep Apnea: It Really Is a Disease by Peter C. Gay, M.D.page 403-405. Journal of Clinical Sleep Medicine, Vol. 4, No. 5, 2008.

Rebecca R wrote:I don't think they've decided if it is or isn't yet.

Well, if you ask me, when somebody gets out the dictionary to preface their comments:

dsm wrote:http://medical-dictionary.thefreedictio ... leep+apnea

mixed sleep apnea,

a condition marked by signs and symptoms of both central sleep apnea and obstructive sleep apnea.
It often begins as central sleep apnea and develops into the obstructive form. Mixed sleep apnea
may also result from obstructive sleep apnea as hypoxia and hypercapnia induce signs and symptoms
of the central form.

Ooops! Sorry! Wrong quote!

Peter C. Gay wrote:Dorland's Illustrated Medical Dictionary (WB Saunders, Philadelphia) defines disease:Disease [Fr. dès from + aise ease] any deviation from or interruption of the normal structure or function of a part, organ, or system of the body as manifested by characteristic symptoms and signs; the etiology, pathology, prognosis may be known or unknown.

it really makes you wonder how much confidence a person has in their position.

I would have looked up/debated "complication" instead of "disease".

Muffy

BTW, a rare telephone interview regarding the JCSM article happened a bit ago:

viewtopic.php?f=1&t=35298&p=309165&hilit=jcsm#p309165

Muffy

Muffy wrote:

Rebecca R wrote:Not to be a troublemaker Muffy, but there are two articles in that journal printed right next to each other in the Pro/Con Debate section. The other one is called Complex Sleep Apnea: It Really Is a Disease by Peter C. Gay, M.D.page 403-405. Journal of Clinical Sleep Medicine, Vol. 4, No. 5, 2008.

Rebecca R wrote:I don't think they've decided if it is or isn't yet.

Well, if you ask me, when somebody gets out the dictionary to preface their comments:

dsm wrote:http://medical-dictionary.thefreedictio ... leep+apnea

mixed sleep apnea,

a condition marked by signs and symptoms of both central sleep apnea and obstructive sleep apnea.
It often begins as central sleep apnea and develops into the obstructive form. Mixed sleep apnea
may also result from obstructive sleep apnea as hypoxia and hypercapnia induce signs and symptoms
of the central form.

Ooops! Sorry! Wrong quote!

Peter C. Gay wrote:Dorland's Illustrated Medical Dictionary (WB Saunders, Philadelphia) defines disease:Disease [Fr. dès from + aise ease] any deviation from or interruption of the normal structure or function of a part, organ, or system of the body as manifested by characteristic symptoms and signs; the etiology, pathology, prognosis may be known or unknown.

it really makes you wonder how much confidence a person has in their position.

OMG!!!

Peter C. Gay, ibid wrote:Several sources provide evidence that CompSA is indeed a defined disease state in the readily accessible literature. Even the website Wikipedia (http://en.wikipedia.org/wiki/Main_Page) states: Patients with complex sleep apnea exhibit OSA, but upon application of positive airway pressure, the patient exhibits persistent central sleep apnea. This central apnea is most commonly noted while on CPAP therapy, after the obstructive component has been eliminated. This has long been seen in sleep laboratories…

WIKIPEDIA???? Where anyone can write anything and anyone can edit it? Give me a break!

I would have looked up/debated "complication" instead of "disease".

Muffy

Ah well, Muffy. Wonderful distinction. But describing a "complication" is far less sexy than being a person who first identified a new disease. As some wise psychologist once wrote in a paper (I paraphrase):"Whether or not everyone has an Oedipus comlex is debatable. But clearly, we all have an Edifice complex". He was referring to those how publish academically....

Perhpase we can refer to compSA as "Gay's Edifice"....

I find it amusing than in one corner, we have:
Dr. Gay who "has received research support from ResMed and has received honoraria for speaking at national and international academic meetings on complex sleep apnea".

While in the other, we have Dr. Malhotra who "has received consulting and/or research support
from Respironics, Sepracor, Pfizer, Itamar, NMT Medical, Apnex Medical, Restore Medical, Inspiration Medical, and Cephalon.
Dr. Wellman who "is a consultant for Repironics".
Dr. Bertisch who "has indicated no financial conflicts of interest".

ResMed is ResMed and Respironics is Respironics, and never the twain shall meet?
O.

Muffy wrote:

Rebecca R wrote:Not to be a troublemaker Muffy, but there are two articles in that journal printed right next to each other in the Pro/Con Debate section. The other one is called Complex Sleep Apnea: It Really Is a Disease by Peter C. Gay, M.D.page 403-405. Journal of Clinical Sleep Medicine, Vol. 4, No. 5, 2008.

OHO...after that grin, I am afraid to read what follows. I have seen grins like that before. I am a deer in the headlights. Okay okay, I was trying to be a troublemaker. I am just so cranky these days. I get cranky when I have to read things four times to figure out what the confusion is about. I get cranky enough with the brain fog when the reading is straight forward. To be a troublemaker, I pointed out that it is there;the fact that Dr. Gay references Wikipedia in a scholarly journal speaks for itself. I know, I Know. You are humoring me.

I am also cranky because I am a research hoarder. I simply cannot look up one article without getting distracted and suddenly I have saved 50 more unrelated articles to read later. I don't have Central Apnea or CompSAS or Mixed Apnea or whatever...so I probably don't really need ALL of the articles I was compelled to collect while looking up Morgenthaler. I did, however, have some central apneas and mixed apneas, the events not the conditions, scored during my sleep study. Sorry I couldn't help myself.

Thanks for the ICSD link. I promise to try to behave. Please don't grin at me like that again Muffy. It frightens me.

ozij wrote:
WIKIPEDIA???? Where anyone can write anything and anyone can edit it? Give me a break!

I find it amusing than in one corner, we have:
Dr. Gay who "has received research support from ResMed and has received honoraria for speaking at national and international academic meetings on complex sleep apnea".

While in the other, we have Dr. Malhotra who "has received consulting and/or research support
from Respironics, Sepracor, Pfizer, Itamar, NMT Medical, Apnex Medical, Restore Medical, Inspiration Medical, and Cephalon.
Dr. Wellman who "is a consultant for Repironics".
Dr. Bertisch who "has indicated no financial conflicts of interest".

ResMed is ResMed and Respironics is Respironics, and never the twain shall meet?
O.

That is amusing.

R

Rebbeca, the break I wanted was from Dr. Gay of course, not you. I'm just saying this in case it wasn't clear....
O.