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rested gal wrote:

dsm wrote:The definitions I read can be summed up in these words Mixed Apnea is a mixture of OSA & CSA
So when I see that quoted line above, I see a clear summary for Mixed Apnea.

dsm, I have a problem (as I've had many a time in the past) with the way you attempt to sum up things.

I think you may be confusing the definition of a term -- Mixed apnea -- with Dr. Ahsan's use of a word -- mixture -- when he mentions Complex Sleep Apnea as a fourth item on that list.

As I understand it (I could be wrong)...

A Mixed Apnea is a single event that has both central and obstructive components within that one apneic episode. It's a single apnea that starts out as a central (no ventilatory effort) but becomes obstructive when an unsuccessful effort to breathe begins. Mixed apneas can show up in the diagnostic part of a PSG sleep study. Mixed apneas do not mean a person has Complex Sleep Apnea.

Dr. Ahsan had already defined:
Obstructive apnea
Central apnea
Mixed apnea

Given that in his list he had already defined those items (briefly, as befits a short bulleted list) I think his fourth item (that you take issue with) is clear enough:

"Complex Sleep Apnea have a mixture of both OSA and CSA"
(colored emphasis mine)

Farther along (page 55) in the presentation, Dr. Ahsan offers a more elaborate explanation of Complex Sleep Apnea.
The word "mixture" is still used:

RestedGal,

I accept you may well be right & as this was never a big deal (until made so) I can accept as I said earlier, that it could be a matter of interpretation of the words. Once again awhy we have forums to discuss these sorts of matters.

Your explanation is a very good one.

Good work

Thanks DSM

rested gal wrote: <snip>
As I understand it (I could be wrong)...

A Mixed Apnea is a single event that has both central and obstructive components within that one apneic episode. It's a single apnea that starts out as a central (no ventilatory effort) but becomes obstructive when an unsuccessful effort to breathe begins. Mixed apneas can show up in the diagnostic part of a PSG sleep study. Mixed apneas do not mean a person has Complex Sleep Apnea.
<snip>

RestedGal,

As you well know this whole topic of SDB is both vast and complex and that is one reason why educated debate on these topics is a wonderful way for us all to learn & explore. The medical profession has trouble enough let alone us mere mortals who are subject to SDB therapy.

Now here is another point for learning & debate. In your definition above I understand we can talk of at least 2 ways of identifying Mixed Apnea - the way you already described, plus - an apnea that starts out as obstructive and becomes a central. I am no expert but that is what I understand & will be happy to have this clarified by polite debate should that POV be wrong.

Again, by debating any of these issues openly & politely, we learn, and that is what I am many others come here to do.

Cheers

DSM

RestedGal,

Seeing you have offered a POV am happy to follow up on this use of the word 'mixture' if you are willing to discuss it.

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.

The word 'combination' fits with other words such as 'includes' (OSA & CSA), 'converts' (OSA to CSA), 'shows as' (OSA then CSA).

JohnBFisher wrote:

rested gal wrote:... As I understand it (I could be wrong)...

A Mixed Apnea is a single event that has both central and obstructive components within that one apneic episode. It's a single apnea that starts out as a central (no ventilatory effort) but becomes obstructive when an unsuccessful effort to breathe begins. Mixed apneas can show up in the diagnostic part of a PSG sleep study. Mixed apneas do not mean a person has Complex Sleep Apnea. ...

Rested Gal, that's exactly how I understand it. And I did ask my sleep specialist.

I will use my own case as an example. I had an apnea index rate that consisted of several obstructive events, one mixed apnea, and many central apneas. In fact there were six times as many central apneas as obstructive apneas. Now, if I had ComplexSAS, my central events would tend to INCREASE as the pressure increases. In fact that was not the case. The central events were pretty evenly distributed. No matter the pressure they were present. In fact, even with the Respironics BiPAP AutoSV unit my prescription used the very top pressure to allow it to help clear my events. No need to limit the pressure.

So, while I have a mixture of events, I do not have ComplexSAS. (Thank goodness. I don't need to handle yet another issue!!)

ComplexSAS includes a mixture of events, but only appears as pressure (therapy) is applied. My central and mixed events exist with or without the pressure.

John

I don't believe anyone is disputing the meaning of Mixed Apnea ?

Cheers

DSM

dsm wrote:... I don't believe anyone is disputing the meaning of Mixed Apnea ? ...

Ah! Further proof that I am just mixed up! Sorry then for my confusion. It is, however, a normal state of affairs for me!

dsm wrote: Ozij is not responding to my point & yes her perspective is fine

I was not?

dsm wrote:I don't believe anyone is disputing the meaning of Mixed Apnea ?

You were not?

I read the following statement as disputing both the definition of Mixed Apnea, and the description of complex apnea.

dsm wrote: The 1st & most obvious mistake is that in slide 4 titled 'SLEEP APNEA' the doc wrote the definitions for
Mixed Apnea & CompSA back to front. An embarrassing slip up & one that still shows in the linked to original.
DSM

I also read it as a rather stern admonishmet of the doctor for making more than one mistake in his presentation.

As to this new issue, of whether people with CompSAS have a "mixture of OSA and CSA", or a "combination of CSA and OSA" that, in my mind is a non-issue, which you did not refer to when talking about the doctor's "first and most obvious mistake".

If you understand CompSAS better when calling it a "combination" of CSA and OSA, and not a mixture, that's fine with me, dsm. It is my impression that Dr. Ahsan's understanding of the sdb is at least as good as yours.

O.

ozij wrote:

dsm wrote: Ozij is not responding to my point & yes her perspective is fine

I was not?

dsm wrote:I don't believe anyone is disputing the meaning of Mixed Apnea ?

You were not?

I read the following statement as disputing both the definition of Mixed Apnea, and the description of complex apnea.

dsm wrote: The 1st & most obvious mistake is that in slide 4 titled 'SLEEP APNEA' the doc wrote the definitions for
Mixed Apnea & CompSA back to front. An embarrassing slip up & one that still shows in the linked to original.
DSM

I also read it as a rather stern admonishmet of the doctor for making more than one mistake in his presentation.

As to this new issue, of whether people with CompSAS have a "mixture of OSA and CSA", or a "combination of CSA and OSA" that, in my mind is a non-issue, which you did not refer to when talking about the doctor's "first and most obvious mistake".

If you understand CompSAS better when calling it a "combination" of CSA and OSA, and not a mixture, that's fine with me, dsm. It is my impression that Dr. Ahsan's understanding of the sdb is at least as good as yours.

O.

Ozij

1) I was being kind due to the spelling of his name & the challenges many have with learning English. There is no other serious professional I can find who uses the word 'mixture' when refering to CompSA. It just does not fit.

2) I have *not* disputed the definition you or RG or anyone else raised in regard to Mixed Apnea - in fact I added to RG's knowledge of the topic & am waiting for her acceptance or denial of the 2 ways that Mixed Apneas occur (Iam now worried that the cat got her tongue )

Maybe instead of saying the esteemed Dr got them 'back to front' I really should have said he created confusion with his CompSA definitions ('mixture') that in fact made them look more like Mixed. I repeat NO Professional in the industry used the word 'mixture' when describing CompSA !.

Cheers

DSM

PS Ozij - I luv ya - you really make me work hard at what I say I respect that greatly ! - RG usually (as she did this time just like many others) pokes me in the eyes & says wanna debate LOL !

dsm wrote:

rested gal wrote: <snip>As I understand it (I could be wrong)...

A Mixed Apnea is a single event that has both central and obstructive components within that one apneic episode. It's a single apnea that starts out as a central (no ventilatory effort) but becomes obstructive when an unsuccessful effort to breathe begins. Mixed apneas can show up in the diagnostic part of a PSG sleep study. Mixed apneas do not mean a person has Complex Sleep Apnea.
<snip>

Now here is another point for learning & debate. In your definition above I understand we can talk of at least 2 ways of identifying Mixed Apnea - the way you already described, plus - an apnea that starts out as obstructive and becomes a central. I am no expert but that is what I understand & will be happy to have this clarified by polite debate should that POV be wrong.

DSM, I don' see the idea you bolded in anywhere Rested Gal's text. Frankly I'm surprised any apnea that starts out as obstructive can eventually turn into a central one, as you seem to imply.
In the spirit of educated debate, would you mind sharing you sources for that? You will notice that whenever I point to a definition, I add the link, so that everyone can read the same text I do. The sharing of sources is a sine qua non of educated discussions.

I would also like to add that I will, of course, not debate a definition made by professionals attempting to describe their subject matter. It is the professionals' prerogative to define. It is for us laymen to use the terms carefully, as defined by the professionals.

So, can you please supply links to professional sources in which a mixed apnea is defined as one that starts obstructive, (airway closed, tremendous breathing effort) and then suddenly breathing efforts stop, the obstruction disappears, and yet breathing is not resumed?

TIA for the links.

O.

Great presentation by Dr. Ahsan IMHO. Thanks for posting that, dsm. Put me down as another reader who didn't see anything wrong with Dr. Ahsan's introductory wording regarding complex sleep apnea----especially in light of that same subject matter's expansion several view graphs later.

Below is another broad-scope presentation that some readers might find complementary to Dr. Ahsan's great presentation. Please be warned that Dr. White's broad presentation below discusses the pathogenesis of both OSA and CSA---and can make for difficult reading since the focus is at times highly technical:

http://ajrccm.atsjournals.org/cgi/conte ... 72/11/1363


(my personal oops note: I originally had the above reply sitting in the wrong thread)

LINK to the article in Sleep

Link to the task force report on the American Academy of Sleep Medicine site

rested gal wrote:

LINK to the article in Sleep

Link to the task force report on the American Academy of Sleep Medicine site

Rested Gal,

I said that 'Mixed Apnea' can be a central that becomes an obstruction or an obstruction that can become a central.

Are you saying that this is *not* the case ???. It is a pretty easy reply to make, yes or no !.

Cheers

DSM

Mixed Apnea
===========
I agree that it doesn't seem to make sense that an obstruction can become a central
& Ozij in a post above has framed questions about how this can occur. RestedGal
has posted a reference to a 2005 Update document that only describes centrals
becoming obstructions. But, there are later publications that explain how
obstructions can become centrals. 2005 is a long time ago in SDB history

Below is the info I have that explains how Mixed Apneas can consist of two variants
Type 1 is the normal & better understood mixed apnea being central=>obstruction, and
type 2 is the less well understood mixed apnea which is when obstruction=>central.

The way I understand an obstruction can become a central is when hypoxia
and hypocapnia triggered by the obstructive phase induce signs & symptoms of a
central apnea as the 2nd phase.
Hypoxia is the lowering of oxygen level. The hypocapnia results from a paCO2 imbalance
(blood CO2 becomes too low) which in turn impacts the respiratory drive. The hypocapnia
signals the sleeper to not breathe while their paCO2 level builds up. One way the
paCO2 level can drop is when the sleeper gasps & hyperventilates momentarily after
the obstructive event & the resulting hypocapnia triggers the central phase.

Below I have highlighted several papers that I understand support this.

DSM

********************************************************************************
(NOTE: This para explains the type 1 then highlights how type 2 can occur)

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2698052/

The occurrence of apnea leads to several consequences that conspire to promote
further breathing instability. The first is the inertia of the ventilatory
control system that prevents the return of rhythmic breathing until PaCO2 increases
by 4–6 mmHg above eupneic arterial PCO2 [19]. In addition, central apnea is
associated with narrowing or occlusion of the pharyngeal airway [20]. Thus,
resumption of ventilation requires opening of a narrowed or occluded airway and
overcoming tissue adhesion forces [21] and cranio-facial gravitational forces.
Termination of central apnea is associated with variable asphyxia (hypoxia and
hypercapnia) and transient arousal, resulting in ventilatory overshoot, subsequent
hypocapnia, and further apnea/hypopnea. This sequence explains the overlap between
central and obstructive apnea (upper airway obstruction often follows central
apneas upon resumption of respiratory effort, i.e., mixed apnea).

................

http://chestjournal.chestpubs.org/content/89/6/800

... in three patients, pauses in inspiratory effort following experimental obstructive apnea were
prevented by administration of 4 percent CO2 and 40 percent O2 inspired gas. This study suggests
that: hyperventilation with hypocapnia occurs at the termination of obstructive apneas, and
hypocapnia may be responsible for the attenuation or cessation of respiratory effort initiating
the subsequent cycle of obstruction.

................

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.

................

dsm wrote:The way I understand an obstruction can become a central is when hypoxia
and hypocapnia triggered by the obstructive phase induce signs & symptoms of a
central apnea as the 2nd phase.

Well, that's not at all what your three supporting references below are saying. Only the first of those three events describe a single-event mixed apnea---and that mixed-apnea description has the central component of that single event occurring before airway closure:

dsm wrote: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2698052/

The occurrence of apnea leads to several consequences that conspire to promote
further breathing instability. The first is the inertia of the ventilatory
control system that prevents the return of rhythmic breathing until PaCO2 increases
by 4–6 mmHg above eupneic arterial PCO2 [19]. In addition, central apnea is
associated with narrowing or occlusion of the pharyngeal airway [20]. Thus,
resumption of ventilation requires opening of a narrowed or occluded airway and
overcoming tissue adhesion forces [21] and cranio-facial gravitational forces.
Termination of central apnea is associated with variable asphyxia (hypoxia and
hypercapnia) and transient arousal, resulting in ventilatory overshoot, subsequent
hypocapnia, and further apnea/hypopnea. This sequence explains the overlap between
central and obstructive apnea (upper airway obstruction often follows central
apneas upon resumption of respiratory effort, i.e., mixed apnea).

What you have in bold above is a single-event mixed apnea starting out central.

dsm wrote: http://chestjournal.chestpubs.org/content/89/6/800

... in three patients, pauses in inspiratory effort following experimental obstructive apnea were
prevented by administration of 4 percent CO2 and 40 percent O2 inspired gas. This study suggests
that: hyperventilation with hypocapnia occurs at the termination of obstructive apneas, and
hypocapnia may be responsible for the attenuation or cessation of respiratory effort initiating
the subsequent cycle of obstruction.

The above excerpt and the rest of that 1986 paper never even describes a single mixed event. Rather, they sequence: : 1) apnea (obstructive), 2) hyperventilation (breathing), 3) hypocapnia (CO2 deficiency), 4) hypopnea (more breathing albeit with undershoot), 5) pauses in inspiratory effort (central pauses). Recall in 1986 the terms CSDB and CompSAS did not exist. That paper talks about overall cycling and ventilatory dyscontrol---not single-event mixed apneas.

You're commenting that a 2005 paper is too old so you counter it with an older 1986 paper?

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.

I think that non-specialized medical dictionary reflects what doctors were sometimes calling CompSAS/CSDB way back in 1986---namely a condition called "mixed sleep apnea". And, in fact, the wording "a condition marked by signs and symptoms of both central sleep apnea and obstructive sleep apnea" describes a condition---not at all a singular clinical event such as a single mixed apnea.

Interesting links, none the less. Thanks for posting those.

SWS

I had not understood Mixed Apnea *had* to be a single event ? -- Does it ?
But I am merely an amateur delving into a very complex environment

Cheers

DSM

dsm wrote:SWS

I had not understood Mixed Apnea *had* to be a single event ?
But I am merely an amateur delving into a very complex environment

Cheers

DSM

If that's true, then the confusion over lexicon in this thread seems to mirror pretty much the same ambiguity and confusion in the medical community prior to 2005 according to Gilmartin, et al:
http://www.ncbi.nlm.nih.gov/pubmed/16217173

A recent report has clarified some of the features of more subtle forms of mixed disease. These include periodic short cycles of obstruction, minimal disease in REM sleep, and incomplete responses to positive airway pressure. Qualitative scoring of this type of disease is limited by imprecision of terms such as 'mixed apnea,' and accurate scoring of central hypopneas is impractical in routine clinical practice. The term 'complex' is used to convey the high likelihood that both obstructive and control factors are involved in creating this pattern of disease

Part of the purpose of that seminal 2005 paper was apparently an attempt to minimize ambiguity of terms regarding "mixed disease"----hence that 2005 proposal to use the term "complex" for the overall condition. Prior to 2005 some medical professionals referred to CSDB/CompSAS as "mixed apnea" while medical professionals also referred to single mixed events as "mixed apneas".

Now they tend to refer to single mixed events as "mixed apneas" while referring to SDB with a mixture of both event types as "complex".