APNEA -v- HYPOPNEA

[quote="inacpapfog"]This "Swift vs other mask" CO2 depletion rate fact is quite interesting! Sure makes sense considering the differences in pressure and mask air chamber sizes! Very interesting !
SWS
Could there also be a "Swift vs other mask" pressure need equation? Does the Swift always inflate a person's general pressure need as compared to other masks?
Let me explain....I have used Swift as my main interface for over a year, switching at times for a 2-5 day stint on the Aura, Activa or UMFF. (HI's have always been my major issue as AI is only .1 or 0.) I feel fine during the day when I use the Swift and because my AHI's have always been below 3, I've been satisfied. I recently bought the Hybrid, seeking to get away from a chin strap and mouthtape. Now, granted I've only used the Hybrid 2 nights, but the drop in pressure and rise in leak rate surprises me! 7.0 and 7.1 pressure as opposed to 10.0 being my average pressure need with Swift. Leaks with Hybrid .35 and .34 as opposed to .05 and less with Swift.

As this new Hybrid users have been reporting over the last several days, I've read the following;
birdiebaby says,
The vent flow on these masks is much higher than the ResMed masks are.
Maybe my Spirit is interpreting this higher air discharge as a leak?
oldgearhead says,
I believe the Hybrid holds the record for CO2 flush holes. At almost 50 L/Min at 10 cm/H2O
Again, it would seem that the Hybrid certainly discharges more volume of air than any other mask does?
maskjkie says,
...the upward force that the chin strap applies, the upper airway actually narrows and the resistance to flow increases. So a higher pressure is needed...
Perhaps this is the sole reason for my lower pressure need ?
Am I thinking right on these issues?

The Resmed machines have specific "mask" settings; Standard, Mirage, Mirage Full etc. They have this because they have specific exhaust port or intentional leak rates keyed into the machine. This is how they are able to give you the Star ***** rating system on mask leak.

Ah hah! So, the leak rate of the Hybrid could read higher/lower depending on which setting I selected on the Spirit? (
I currently have it set on the Mirage. What should I set it on?)

APAP/Swift

AHI=6.5;AI=0.7;HI=5.8;Pressure (95%)=8.8.

Fascinating, ain't it??????

Chuck

Very fascinating, Chuck. I can't wait for the reintroduction of 8 cm fixed pressure to Swift. So far it appears that you can manipulate your HI at will by manipulating those factors influencing CO2 depletion.

Now there's a seemingly opposite twist going on in another thread. In that thread we appear to have posters who seemingly get better HI scores by accelerating their CO2 depletion. That would be the exact opposite case of CSDB. CSDB is currently defined as a case of hypocapnic trigger. The other posters, by contrast, appear to manifest an ever so mild case of a hypercapnic trigger (measurement/manufacturer compatibility considerations may come into play in some of those posts, however). Respiratory similarities between the hypocapnic and hypercapnic cases of central induction? In both cases we potentially have the same maladjusting homeostatic CO2 respiratory trigger at play. Both are believed to be cases of hypercapnic respiratory drives or "CO2 misadjusted" respiratory drives. Both are potentially cases of short-term homeostatic maladjustment: one with a hypercapnic central apnea trigger and the other with a hypocapnic central apnea trigger. Both cases are influenced largely by CO2 kinetics.

The hypocapnic CSDB case is the new discovery. Frank pressure-influenced central apneas in response to a hypercapnic threshold is the old discovery. The old school of thought relating to those statistical 8 cm to 10 cm barriers was derived with a vague understanding of that hypercapnic triggering mechanism. The new CSDB discovery says that there are now some patients with a twitchy hypocapnic threshold instead. The new school of thought also recognizes that there is a gradual gradation of effects regarding the induction of central events, not merely the onset of frank central apneas at any given hard barrier. The new school of thought now says that CO2 considerations will be necessary in the evolving field of SDB medicine/therapy.

Are we convinced yet that "one size does not fit all" regarding xPAP therapy? The diversity and uniqueness of physiology in general and etiologies in specific are precisely why xPAP trail-and-error and even mask trial-and-error have been the best friend of quite a few patients on this message board.

I think this whole topic is fascinating. And I can't wait to see how Chuck's data continues to play out.

I often wonder what makes the AHI jump around so much with the exact same mask and exact same machine and exact same numbers. I do realize the APAP is fluctuating all the time. Maybe THAT is the key to this mystery. I've been trying a few things with my xPAP also, mainly going from min pressure of 8 to 10. And max pressure of 17 down to 16. +3/-3 And I tend to leave my note book with the data at home on a daily basis but I remember my AHI shooting up to 10 something today. My max pressure had gone up to 16 last night. Up to this point it's NEVER gone this high with the recent (new) pressure settings, but that's not to say it doesn't hit it's ceiling from time to time. I had a few beers the night before last. HA! By few I mean 7. My numbers were ok the first night, just about 1 cm of pressure higher than the night before. But last night both shot up. And it would seem that as my max pressure went up, so did my AHI, specifically, my HI.

If this is the case, then raising my minimum pressure from 8 to 10 wasn't such a great idea. I might want to lower it back to the original 8 to 17 settings the doctor prescribed. While I want to take control of this therapy, I don't have many guidelines to go by and thus have to rely on what the doctor prescribed. This is assuming the doctor actually had anything to do with that setting in the first place.

Rasta:

If you haven't read my recent posts on pressure and AHI, If you scroll back on this thread, I have posted my experience with pressure and AHI.

While your situation probably is very different from mine - there might be some relevance or thought for you there.

Best,

Tom

APAP/Swift

AHI=5.4;AI=0.4;HI=5.4;Pressure (95%)=9.4.

Slept poorly, feel rotten.

Though I believe in scientific method, I'm thinking of D/Cing this APAP trial and going back to CPAP at 8.0cmH2O. But, I'm gonna try to go a full week.

I'll keep you posted.

Chuck

Chuck,

If you're starting to feel like it's affecting your energy and daily routine, take a breath, regroup, and when you're ready, try again - if you feel so inclined. You're been at this awhile and if it's playing games now with your well being during the day, you can just walk away for a little bit.

I know how much you do in a day and how badly you need to be at the top of your game. Thank goodness you know your settings/masks combos that will ensure you can feel that way and all you have to do is go back to that for a few days...or for however long you feel you want to before recommencing the experiment. Like I keep telling you, you are one of the fortunate ones in that regard.

Chuck, my opinion only. We can never execute the scientific process on a message board. What we have speculated about in this thread might be considered "the very front end of the very front end" of the scientific method. Your health is the primary consideration here. I suggest going back to 8 cm fixed pressure and calling it a day. Then in future days consider titrating down with your doctor in the loop.

The only pure and scientific conclusion that can come out of this is that we have discovered a good therapeutic combination for Chuck... But we certainly have generated plenty of fodder for future consideration.

-SWS wrote:we certainly have generated plenty of fodder for future consideration.

This thread has contained some pretty complex (no pun intended! ) discussions. Quite fascinating. The reasoning you bring to your hypotheses and speculations, -SWS, is a treat to watch in action. I hope you keep hauling that wagon to the silo as often as you can!

RG (or any one else with some good technical savvy)-

Once again, could you help me to paste some graphs from an Excel workbook into a post on this thread???? I have some wonderful graphs , a 3-D one in particular that is VERY revealing.

I use my Macintosh TiBook for this purpose and I'm using Microsoft Office 2004 for Mac. Therefore, advice on how to do this inthe Wintel world doesn't help (leastwise, I'm not smart enough to translate it to a Mac).

Thanks in advance. I'm anxious to share these graphs of the data that I've been carefully collecting with you folks for all to see.

1. You will need a way to turn these items into a "jpg" or "gif". In Windows "Prt Scrn" works fine. You could also print them and then scan them into a jpg.

2. You will need a place to post them on the web, I use PhotoBucket.com, it is free.

3. Transfer your jpgs or gifs to the web site and post a "URL" to them on Cpaptalk.com and your finished.

Hope this helps,

Bob

Chuck,

1) Perform a series of Macintosh "screen dumps" while viewing your spread sheets

2) Save each of those "screen dumps" to an image file

3) Upload each screen dump file to one of the free picture-hosting services such as photobucket.com

4) Submit each image in your cpaptalk.com posts by using the "Img" button as you compose (you will need to point your cpaptalk.com thread that is being composed to each picture's URL/web-address location on photobucket.com---don't forget to use "Close Tags" after copying/pasting each image address as well---the result should look like this: [img]web-URL-address-of-image-goes-here[/img])

5) Discuss and enjoy

Here's a Google search for "macintosh screen dump":
http://www.google.com/search?q=%22macin ... S:official
That first Google return gives instructions for two older Mac OS'es, but they will probably work on the newer OS'es as well.

Here's a URL to photobucket.com's FAQ:
http://photobucket.com/faq.php

Hope this helps, my friend!

GoofyUT wrote:RG (or any one else with some good technical savvy)-

Once again, could you help me to paste some graphs from an Excel workbook into a post on this thread???? I have some wonderful graphs , a 3-D one in particular that is VERY revealing.

I use my Macintosh TiBook for this purpose and I'm using Microsoft Office 2004 for Mac. Therefore, advice on how to do this inthe Wintel world doesn't help (leastwise, I'm not smart enough to translate it to a Mac).

Thanks in advance. I'm anxious to share these graphs of the data that I've been carefully collecting with you folks for all to see.

Just Google search for a "PDF writer for Mac", most are freeware, such as CutePDF writer, you install it, then print your spreadsheet to the PDF selected printer.

When you install the PDF writer it shows up just like another printer (but it is a virtual printer), then it prompts you for the filename.pdf to use for the document. Then you can post the pdf document just like a .jpg, .gif or other file, you have to be careful on the size and not post a 3Gig file.

With tremendous thanks for the help offered by RG, Snoredog, SWS, Bob and ESPECIALLY the wonderful Lori, here's a graph representing my experiences over the past few weeks as I experimented with APAP -v- CPAP, Swift -v- Activa, good -v- evil, France -v- Italy, and of course, American League -v- National League.

I hope that this helps at least one of you!



Chuck