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Why is pressure changing by 1.5 cm H2O? - Asking because my spinal joints hurt
#31
(04-12-2016, 01:36 PM)green wings Wrote: Thanks for this info, RobySue. Is information about the PR Auto's algorithm available, either in text form or in equation form, online?
There used to be some pretty useful information about the PR Search algorithm on the PR pages that were accessible to patients. They seem to be long gone. Oh-jeez

If I get a chance I'll try to find some links that are still live. Some of the links, however, may point to sites that are no allowed by the forum rules.

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#32
(04-12-2016, 01:36 PM)green wings Wrote: Thanks for this info, RobySue. Is information about the PR Auto's algorithm available, either in text form or in equation form, online?

I find the information that you give about the algorithm to be very interesting, and I do want to know why the algorithm is reacting in the way that it does, because sometimes it certainly isn't obvious.

I used to work in process control in the 1980s and 1990s, and even though my knowledge of that field is rusty and outdated, I would love to know more about how the PR algorithm works.

Ditto for the Resmed algorithm.

I'm not sure if the pressure changes from the algorithm searching were a problem for me or not. It's very hard to tell. Plus, I have fibromyalgia, which by definition means that my pain perception threshold is not normal, so I'm prone to "princess and the pea" behavior. Bag-head

Back when I was a newbie (over 5 years ago) I had significant "princess and the pea" problems with the Resmed Auto algorithm. Those sharp increases in pressure caused by flow limitations would not only wake me up at times, they'd give me serious aerophagia.

The PR Search algorithm on my PR BiPAP, however, has never been an issue. The linear 2cm increase in pressure in the search algorithm feels quite tame compared to the Resmed aggressive increases in pressure.

Fact is: Some people find the PR Search algorithm irritating and some people find the Resmed's overly aggressive pressure increases in response to flow limitations and snoring irritating.
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#33
(04-12-2016, 12:59 PM)green wings Wrote: Paula,

I'm not sure what you mean about making changes so quickly. Do you mean stopping the two auto trials because of discomfort?

Aside from the two short auto trials, the rest of my 2.5 months use of CPAP has been spent increasing my therapy pressure from the original prescription of 7.0 cm to a current 10.0 cm.

Yes. Five days here and there do not give you nor your body time to adjust. Those of us with chronic pain have to take things slower and give stuff time. Unless the pain got worse each night (as in it accumulated), you need to give it time.

You also say you had it set to 9 to 10.5? That's an awful tight range. A wider range would let your body rest between events and acclimate to the pressure better. If your current is 10 and is going good for you, and if it were me, I would go 8 to 12. And I would nap with it. And I just might set an alarm for the middle of the night so I can shift position or do a body check.

Actually, I wonder if sitting up during the day with the mask on and the machine on would help any? You are at 10 now so I don't think the pain is from the pressure of the machine. It could be as simple as you sleep in the same position for too long.
PaulaO2
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#34
(04-11-2016, 05:42 PM)robysue Wrote: Once again, I feel the need to come to the defense of the PR Auto's Search Algorithm.

Things are not quite as simple or as backwards as Palerider is suggesting.

The Search algorithm does kick in when the breathing appears to be normal:

I googled part of Dave's comment on the subject, and found this:

http://www.google.ch/patents/US20120152252

in case you're interested.
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#35
Thanks, palerider - that's exactly what I was hoping to see. like

I just spent 20 minutes scanning part of it and have saved it as a PDF file to print out and look at more closely.

It's been quite a few years since I've tried to read that sort of technical document. Arrgh. Grin

(04-12-2016, 05:10 PM)palerider Wrote:
(04-11-2016, 05:42 PM)robysue Wrote: Once again, I feel the need to come to the defense of the PR Auto's Search Algorithm.

Things are not quite as simple or as backwards as Palerider is suggesting.

The Search algorithm does kick in when the breathing appears to be normal:

I googled part of Dave's comment on the subject, and found this:

http://www.google.ch/patents/US20120152252

in case you're interested.

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#36
Thanks for your reply, RobySue. Smile

I started trying to use CPAP therapy a couple of months before I found this forum. I started off at 7.0 cm and swallowed a whole bunch of air. I woke up from a dream that I had swallowed a giant Zip-Loc bag and couldn't figure out how to get it out of my stomach.

Definitely PATP (princess and the pea).

(04-12-2016, 03:55 PM)robysue Wrote: Back when I was a newbie (over 5 years ago) I had significant "princess and the pea" problems with the Resmed Auto algorithm. Those sharp increases in pressure caused by flow limitations would not only wake me up at times, they'd give me serious aerophagia.

The PR Search algorithm on my PR BiPAP, however, has never been an issue. The linear 2cm increase in pressure in the search algorithm feels quite tame compared to the Resmed aggressive increases in pressure.

Fact is: Some people find the PR Search algorithm irritating and some people find the Resmed's overly aggressive pressure increases in response to flow limitations and snoring irritating.

Post Reply Post Reply


#37
Oh right, I know that five days isn't a good trial. The pain was getting worse in an accumulating fashion, as inflammatory pain often does if you're doing something repeatedly. That's why I bailed like a big chicken after night 5.

Agree with rest of what you wrote as well. Thanks for your analysis.

I'll try to rein in the impatience. Bag-head


(04-12-2016, 04:01 PM)PaulaO2 Wrote: Yes. Five days here and there do not give you nor your body time to adjust. Those of us with chronic pain have to take things slower and give stuff time. Unless the pain got worse each night (as in it accumulated), you need to give it time.

You also say you had it set to 9 to 10.5? That's an awful tight range. A wider range would let your body rest between events and acclimate to the pressure better. If your current is 10 and is going good for you, and if it were me, I would go 8 to 12. And I would nap with it. And I just might set an alarm for the middle of the night so I can shift position or do a body check.

Actually, I wonder if sitting up during the day with the mask on and the machine on would help any? You are at 10 now so I don't think the pain is from the pressure of the machine. It could be as simple as you sleep in the same position for too long.

Post Reply Post Reply
#38
(04-15-2016, 11:53 AM)green wings Wrote: Thanks, palerider - that's exactly what I was hoping to see. like

I just spent 20 minutes scanning part of it and have saved it as a PDF file to print out and look at more closely.

It's been quite a few years since I've tried to read that sort of technical document. Arrgh. Grin

the real treasure will probably be found digging through referenced patents... which, of course, means MORE mind bending work.... Bug-eyed
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#39
I'm sure you're right. After some initial distress at how difficult I've found it to even import data into SleepyHead and try to understand it, I decided to try to relax about the whole thing.

There's some major irony when you first start trying to adjust your xPAP settings, because you're using your O2-deprived brain to try to figure out how to get the right amount of O2 to your brain. (To greatly oversimplify the problem.)

I think that emoticon you used has the same glasses prescription as me. Crazy

(04-15-2016, 01:14 PM)palerider Wrote: the real treasure will probably be found digging through referenced patents... which, of course, means MORE mind bending work.... Bug-eyed

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#40
(04-15-2016, 11:58 AM)green wings Wrote: Thanks for your reply, RobySue. Smile

I started trying to use CPAP therapy a couple of months before I found this forum. I started off at 7.0 cm and swallowed a whole bunch of air. I woke up from a dream that I had swallowed a giant Zip-Loc bag and couldn't figure out how to get it out of my stomach.
On my third night of PAPing I dreamed I was an intelligent goose that realized that I was being "fattened up" for fois gras by being force fed more air than I could ever possibly manage to breath in on my own. And I knew (in the dream) that there was nothing I could do to prevent my ultimate fate of exploding into little fois gras hors d'oeuvres at some rich person's cocktail party.

That's one of the most disturbing dreams I've ever had in my life. And I woke up feeling like I'd swallowed a basketball.

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