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Re: Sandman Auto
Posted: Wed Aug 20, 2008 7:30 am
by Slinky
Uh, er, DreamStalker, that wasn't central apneas, Echo was asking about. It was central HYPOPNEAS. We've seen a couple of light discussions about central hypopneas, what they are, do they really exist, what determines what they are, etc. There doesn't seem to be much information about them and they are only recently "recognized" as I remember it.
Re: Sandman Auto
Posted: Wed Aug 20, 2008 7:32 am
by echo
I know what a central apnea is, but I didn't realize you could have central hypopnea's either.
Edit: Slinky, ha ha you beat me to a post AGAIN
Re: Sandman Auto
Posted: Wed Aug 20, 2008 8:02 am
by -SWS
An obstructive hypopnea is a hypopnea that occurs because of airway narrowing. A central hypopnea is a hypopnea that occurs because of lesser central respiratory effort.
Warning- My Interpretation Only: I think this machine scores obstructive hypopneas only when these two-fold criteria are met: a) adequate amplitude reduction occurs (the "height" of the breath signal is too short), and b) an "obstruction like" or "FL like" wave shape is superimposed on that amplitude-reduced flow signal. I also think the remaining hypopneas are simply relegated to the central hypopnea category by default. That would mean obstructive hypoponeas are explicitly differentiated and central hypopneas are implicitly differentiated by defaulting into their category. Who knows what the specificity and sensitivity ratings are for this type of hypopnea differentiation? I honestly don't think they can be very high compared to a PSG---where they also have difficulty routinely differentiating central from obstructive hypopneas with far better equipment.
So the above speaks of differentiating obstructive from central hypopneas. By contrast this APAP algorithm uses the detection of cardiac oscillation signals (or "heartbeat" detected through an open airway) to differentiate central apneas from obstructive apneas. I do not think that same cardiac-oscillation technique would lend itself to hypopnea differentiation since the airway is open during both types of hypopneas. Even amplitude analysis of that "heartbeat" signal toward hypopnea differentiation would get fairly dicey IMO.
Re: Sandman Auto
Posted: Wed Aug 20, 2008 9:48 am
by -SWS
-SWS wrote: Warning- My Interpretation Only: ...I do not think that same cardiac-oscillation technique would lend itself to hypopnea differentiation since the airway is open during both types of hypopneas.
I just now took a look at the patent description and I have to retract my above speculative statement about hypopnea differentiation. Here's the part of the patent description that allows for cardiogenic oscillations to be used as
one of several criteria in assessing elevated airway resistance associated with obstructive hypopneas (the bold emphasis below is mine):
United States Patent 6739335 wrote: The present invention also provides a method for resolving an ambiguity in breath monitoring to determine whether or not breathing is labored due to an obstruction, by the presence or absence of cardiogenic oscillations. According to the present invention, identification of inspiratory flow limitation can be accomplished with improved accuracy even when the breaths show a shape which is intermediate between definitely abnormal shape (flow limited) and definitely normal sinusoidal shape. This is accomplished by further examining whether there is cardiogenic oscillation present during expiratory periods and between breaths. This is detected by signal processing to enhance and identify small oscillations in the flow signal in the range of the pulse frequency in the range of the pulse, which oscillations represent cardiogenic oscillations. When these oscillations are detected, and breath whose shape is possibly abnormal, i.e., ambiguous, the breath may be classified as normal. When oscillation is absent, the threshold of the parameters used to classify the the shape of the inspiratory airflow abnormal is lowered and the breath is classified as having a high resistance. This technique is used to make the decision as to whether therapeutic CPAP pressure needs to be raised for obstructive events. It has the benefit of avoiding false positive detection of abnormally shaped breaths causing excessive rise in pressure in those patients who have them, while not sacrificing sensitivity to abnormal events in those who are more classical. The inspiratory flow signal, both amplitude and contour, and the presence or absence of cardiogenic oscillations on the flow signal are used to define the state of resistance of the upper airway.
So cardiac oscillations are definitely used to differentiate central from obstructive apneas. But cardiac oscillations are also used to
help differentiate central hypopneas from obstructive hypopneas---specifically when flattening or "obstruction-hinting" wave shape of the hypopnea's flow signal is ambiguous (i.e. the flow signal is not quite sinusoidal or perfect, but not properly FL shaped either). That's when cardiac oscillations enter the hypopnea differentiation routine.
I think this prior statement is still true but needs to be appended to account for thoracic and abdominal muscular effort getting slightly out of phase with one another (not a case of lesser or marginally diminished central respiratory effort).
An obstructive hypopnea is a hypopnea that occurs because of airway narrowing. A central hypopnea is a hypopnea that occurs because of lesser central respiratory effort.
See additional central hypopnea dynamics in physiology described below:
http://www.sleepreviewmag.com/issues/ar ... -04_07.asp
Sleep Review Magazine wrote:Central hypopneas are associated with reductions of purely in-phase thoracic and abdominal effort or movement signals, followed by an increase in chest and belly movements at the end. There is no evidence of phase shifting or paradoxical breathing, no airflow flattening, and no snoring throughout the entire central hypopnea.
Re: Sandman Auto
Posted: Wed Aug 20, 2008 10:23 am
by echo
Ahh, thanks for the sleuthing and the info SWS! I'll have to read it sometime when my mind is clear.
Re: Sandman Auto
Posted: Wed Aug 20, 2008 10:59 pm
by rested gal
Thunder Road wrote:The new software does not include the 96 report you referenced.
Oh no! I really hate to hear that. The 96 hour graph was the
only thing I looked at when using the 420E and Silverlining software that the Sandman machine and Sandman software are based on.
If they've left that graph out of the Sandman software.... darn.
Re: Sandman Auto
Posted: Thu Aug 21, 2008 12:22 am
by Snoredog
rested gal wrote:Thunder Road wrote:The new software does not include the 96 report you referenced.
Oh no! I really hate to hear that. The 96 hour graph was the
only thing I looked at when using the 420E and Silverlining software that the Sandman machine and Sandman software are based on.
If they've left that graph out of the Sandman software.... darn.
I wonder if there isn't a switch to enable it, like you I am perplexed at why they would remove that report graph, probably the most informative graph in the whole package.
I recall in the earlier versions of Silverlining there was a report template screen (currently on my Macbook so I don't have it immediately available), in it you could customize reports to display the panels wanted. I wonder if that area of the software still exists and what the defaults are, I'll have to fire up my Sony laptop and check it out. I remember when the 420 came out, Silverlining available didn't support it, Ted and I hacked it from his 416P version and got it to work with the 420. They may have come out with a patient version and removed it. Hopefully there is a clinical version.
Re: Sandman Auto
Posted: Thu Aug 21, 2008 5:30 am
by ozij
rested gal wrote:Thunder Road wrote:The new software does not include the 96 report you referenced.
Oh no! I really hate to hear that. The 96 hour graph was the
only thing I looked at when using the 420E and Silverlining software that the Sandman machine and Sandman software are based on.
If they've left that graph out of the Sandman software.... darn.
It's called "Detailed Record" in Silverlining. Don't you ever get to see those details?
Maybe they're still working on the software - cpap.com was selling version 1.0 and then version 1.1 .... That detailed record is
so helpful!
O.
Re: Sandman Auto
Posted: Thu Aug 21, 2008 8:27 am
by Hawthorne
Don't know if I get what you are talking about when you say the 96 hour report but a member using Sandman sent me this along with his 8 page report. He said if you click on the date you get this.
I don't think he will mind me posting it since there is no ID here.
Re: Sandman Auto
Posted: Thu Aug 21, 2008 8:47 am
by -SWS
Below is the right-most portion of a Silver Lining detailed report. That picture is missing quite a few hours to the left, but you can still get an idea of what the report looks like. Is there anything like that hiding in the new software?
Re: Sandman Auto
Posted: Thu Aug 21, 2008 10:14 am
by Thunder Road
This report is available with the Sandman software. It is in the WaveForm report of the software. It seems to not print but you are able to view it. Sandman 1.1 is for the Auto and Info model providing detailed data while the 1.0 is compliance only software for the intro model. Hope this helps. It really is a fine APAP.
Re: Sandman Auto
Posted: Thu Aug 21, 2008 10:19 am
by ozij
Yay!
I have no doubt that what you've just heard is a collective sigh of relief.
O.
Re: Sandman Auto
Posted: Thu Aug 21, 2008 10:34 am
by -SWS
Thunder Road wrote:This report is available with the Sandman software. It is in the WaveForm report of the software. It seems to not print but you are able to view it. Sandman 1.1 is for the Auto and Info model providing detailed data while the 1.0 is compliance only software for the intro model. Hope this helps. It really is a fine APAP.
ozij wrote:
Yay!
I have no doubt that what you've just heard is a collective sigh of relief.
O.
Yup!
Thanks for the info Thunder Road!
Re: Sandman Auto
Posted: Thu Aug 21, 2008 1:29 pm
by Snoredog
-SWS wrote:Thunder Road wrote:This report is available with the Sandman software. It is in the WaveForm report of the software. It seems to not print but you are able to view it. Sandman 1.1 is for the Auto and Info model providing detailed data while the 1.0 is compliance only software for the intro model. Hope this helps. It really is a fine APAP.
ozij wrote:
Yay!
I have no doubt that what you've just heard is a collective sigh of relief.
O.
Yup!
Thanks for the info Thunder Road!
Yup! Yup! Yup! I know the next machine I'll be getting. But man I had a rough night last night, woke up couldn't breathe, felt like I had a golf ball in my throat way down LOW like in the adams apple, guess I had a vocal cord closure, I really panicked I could not breathe then it popped open and I gasp for air, by then I was sitting up with the mask off. Freaky deal, never had one of those before and hope I never have another.
Re: Sandman Auto
Posted: Thu Aug 21, 2008 1:54 pm
by jnk
Snoredog wrote:. . .I had a rough night last night, woke up couldn't breathe . . .
Please be careful, Snoredog. We need you.
jnk