CPAPtalk.com

DanOtn wrote:Thanks for the answer!

What kind of issue's would point to a pressure problem?

For pressure being too low, the usual issue is that the AHI is not reduced to levels below 5.0. Although in that case it's not always easy to just fix the problem by increasing pressure.

For pressure being too high? Well, in my case, aerophagia, air getting into my eyes through my tear ducts, and a serious crash and burn in terms of day time functioning due to severe sleep deprivation that STARTED immediately after I started CPAP were among the symptoms that lead my PA to first recommend a week of autotitration that lead to a pressure decrease from straight 9cm to APAP range of 4--8cm. Continued (but reduced aerophagia) and continued crash & burn with sleep deprivation symptoms lead to the recommendation for a bi-level titration and a switch to a BiPAP. Continued aerophagia issues popping up in my insomnia sleep log lead to the recommendation for a second bi-level titration, which lead to the BiPAP levels being reduced from 8/6 to 7/4.

And... is there a minimum pressure... where the insurance might say "this person doesn't need CPAP/APAP"?

I don't think so. The critical thing that determines the need for CPAP/APAP is the AHI or RDI on the diagnostic sleep study. (Whether it's the AHI or RDI depends on how the lab scores certain things.) It might be unusual, but it is possible for a person who has really severe OSA (diagnostic AHI well above 30) to only need a minimum pressure of 4 or 5 cm to bring that AHI down to less than 5. It's also possible (and not that unusual) for a person with fairly mild OSA (diagnostic AHI between 5 and 15) to need a pretty high pressure setting---say above 12---to properly splint their airway open. The amount of pressure you need is more determined by the structures in your throat and how they react to the pressurized air being blown down your throat rather than the overall severity of your OSA.

I've never heard, nor is it logical, that severity and titrated pressure are related.

One is entirely dependent on the number of events, while the other is the pressure required to keep the airway open.

It's like saying how fast you can walk depends on your shoe size...

LinkC wrote:I've never heard, nor is it logical, that severity and titrated pressure are related.

One is entirely dependent on the number of events, while the other is the pressure required to keep the airway open.

It's like saying how fast you can walk depends on your shoe size...

Ahhh that there is a funny parallel you chose to draw.

Using logic and statistics, statistically people with LARGE feet and hence a larger shoe size, tend to have longer legs. People with longer legs tend to walk FASTER and even run faster than those with shorter legs. OOOPS

I know this is an old thread, but it seems to have popped up due to new votes.
When the thread was new, I was in my eighth month of using my S9 Elite;
thus had no experience with which to compare.
Having used my Autoset since February, I can definitively say that I prefer the Autoset over the Elite.
I was originally titrated at 14 cm, but with the Autoset, my pressure usually hovers between 11 and 12,
with an occasional jump ABOVE 14, (still with insignificant "centrals").
I do not know why this happens, but it is nice to know that I am covered when it does.
One can but wonder how many others have irregular pressure needs. . .

I have only been on c pap for about 9 nights. I am complying but my ahi's are high. So last night I put it into a pap mode. my pressure was 10, so I set it at 8 min. 14 max. Had quite a bit of leakage last night, which I did not have before. The noise woke me up about 3 times. So now I have to readjust my mask.. probably tighten it a bit. After a few days will put the data on my computer to see what my info reads and go from there.

chunkyfrog wrote:I know this is an old thread, but it seems to have popped up due to new votes.
When the thread was new, I was in my eighth month of using my S9 Elite;
thus had no experience with which to compare.
Having used my Autoset since February, I can definitively say that I prefer the Autoset over the Elite.
I was originally titrated at 14 cm, but with the Autoset, my pressure usually hovers between 11 and 12,
with an occasional jump ABOVE 14, (still with insignificant "centrals").
I do not know why this happens, but it is nice to know that I am covered when it does.
One can but wonder how many others have irregular pressure needs. . .

What are your settings on auto? And do you use EPR?

You missed one: vpap asv

Didn't realize it was old either. I've been on straight CPAP for a decade. Personally I think that a data capable APAP is the best of "most" worlds. As robysue pointed out an auto can help to refine or tweak settings and for a number of people I understand it is more comfortable.

As for therapy and longevity on the machine, I'm, not yet convinced that an APAP is always best therapy if a wide range is used. for example, if my CPAP pressure is 10 or 12 or ???, then personally I would setting an APAP at that pressure for the minimum. That should prevent a lot of ramping up and down in pressure. In some ways it puts the machine in CPAP mode with the extra security of being able to go up in pressure for one of those rougue apneas that needs more pressure.

The other side of the coin, what is rarely talked about is if there is any impact on a machine if it is constantly ramping up and down all night long as opposed to running at a set speed. Will a CPAP last longer than an APAP? That I don't know.

John

70sSanO wrote:if my CPAP pressure is 10 or 12 or ???, then personally I would setting an APAP at that pressure for the minimum. That should prevent a lot of ramping up and down in pressure. In some ways it puts the machine in CPAP mode with the extra security of being able to go up in pressure for one of those rougue apneas that needs more pressure.

That's the way I set the minimum pressure with any autopap I use, too. And is the way I set the "minimum EPAP" pressure with any bilevel auto I use.

Here are some links to my thoughts about why setting the minimum pressure is the most important setting to "get right" when using any kind of autotitrating machine... the minimum pressure in the range for an autopap, or the min EPAP for autotitating bilevel (BiPAP Auto or VPAP Auto) and the EPAP for plain bilevel (BiPAP or VPAP.)

Autopap (minimum pressure):

Results: 1st night with Auto A-Flex (topic started by TSSleepy)
Two nights graphs posted using pressure range 4 - 20 and 10 - 20
viewtopic.php?p=349073#p349073

November 2008 Just got an APAP (topic started by turbosnore)
viewtopic.php?p=319619#p319619

October 2008 Turning off Aflex and Cflex (topic started by DoriC)
viewtopic.php?p=307265#p307265

September 2008 New Guy - Need Help w/Settings (topic started by alanhj13)
viewtopic.php?p=294319#p294319

Wulfman, DreamStalker, and ozij explain why autopaps make changes slowly.
December 2008 Why adjust APAP. Isn't it auto? (topic started by oxygenium65)
viewtopic.php?p=323218#p323218


________________________________________________________

BiPAP (EPAP) and BiPAP Auto (min EPAP):
May 2008 - discussion with RonS about importance of EPAP setting.
viewtopic.php?p=265020#p265020

February 2008 - EPAP is generally lower than the single pressure from a "CPAP" titration.
viewtopic.php?p=245757#p245757

December 2007 - my understanding of how a bipap titration is done.
viewtopic.php?p=231786#p231786

I started with an M series APAP and by experimenting I found that my apneas increased when my pressure was too high. On that machine I did better in Cpap mode. I've read about that happening to some people. ThecSandman didn't do that so I ran it as an APAP. I'm currently running s9 autoset as an APAP but will experiment and then decide.

Mindy

Some of us see a big difference between CPAP and APAP. I tried CPAP with my APAP for just a few nights a couple years ago, with the CPAP pressure set to what I believed to be my 'titrated pressure', and felt far worse afterwards. And even though the range of the APAP was not terrible large, and centered around my titrated pressure, the auto mode gave much better results. Switching to an ASV machine validated my need to fast-responding automatic pressure adjustment.

Overall, I find my treatment much better while on APAP than on CPAP with same pressure of 13 cm. See it here that the pressure graph almost never touches the top line of 13 cm:






If I try to compare the above graphs made from S9 Autoset in APAP mode to those I have from the same machine in CPAP mode , the most similar pressure that I have is the following. Also, while doing the graphs from the APAP I used a combination of a Resmed Mirage Nasal mask and a chinstrap the graphs that I am showing below for CPAP mode were done while I used the F&P FF Flexifit #431:







Here is another example of my Stats in CPAP mode. In this case I don't have graphs but at this time I used the same mask and chinstrap as in the APAP mode above:




It is obvious that in my case, using the APAP mode is much better.

I am not surprised about my better treatment with the APAP.
You just need to read what Resmed's chief designer of the Autosets said about these machines:


From an interview with Dr Michael Berthon-Jones, in 2002.

Q. Why is it important for an automatic CPAPdevice
to respond to flow limitation, snore and apnea?

A.The characteristic flattening of the flow-time
curve caused by flow limitation is the very best
signal for fine-tuning the pressure, once you have
eliminated apneas and snoring. But if you are just
falling asleep, you can go very quickly from having
a totally open airway to snoring very loudly, in a way
that produces somewhat chaotic or messy flowtime
curves, without seeing the characteristic
flattening. So the best approach is to respond very
quickly to loud snoring, and then fine tune using
flattening. Rarely, you can go straight from awake
and unobstructed to asleep and apneic, and so it
can be useful to increase pressure in response to
apnea as well. However, actual apnea is pretty rare
on AutoSet, because in most cases the responses
to snoring and flattening get the pressure up
quickly enough to prevent apneas.


Q.Why doesn’t ResMed's AutoSet respond to
hypopnoea?

A.When you are lying quietly awake, or when you
first go to sleep, or when you are dreaming, you
can have hypopneas (reductions in the depth of
breathing) which are nothing to do with the state of
the airway. For example if you sigh, which you do
every few minutes, you usually have a hypopnea
immediately afterwards. This can also happen if
you have just rolled over and are getting settled, or
if you are dreaming. And the annoying thing is that
when you are on CPAP, this tendency to have what
are called central hypopneas - hypopneas that are
nothing to do with the state of the airway - is
increased. If you make an automatic CPAP device
that responds to hypopneas, you will put the
pressure up to the maximum while the patient is
awake.

Q.Do you think there is a misconception clinically
that all hypopneas should be treated ?

A.For simple obstructive sleep apnea, central
hypopneas should not be treated. They are not a
disease. Everyone has them. And they don’t go
away with CPAP.

There is a rare and important exception: central
hypopneas due to heart disease. This is called
Cheyne-Stokes breathing. CPAP does help with
that.

Q.Why doesn’t ResMed's AutoSet respond to
apnea above 10 cmH2O in pressure?

A.I mentioned before that the higher the pressure,
the more central hypopneas you will have. At a
pressure somewhere around 10 cmH2O, the central
hypopneas become central apneas. On the other
hand, the vast majority of obstructive apneas are
already well controlled by 10 cmH2O, and we are
only fine tuning using snoring and flattening. So it
is a pretty good bet that if the pressure is already
above 10 cmH2O, any apneas are most likely
central, and you should leave them alone (except
in patients with central apneas due to heart failure).
But if the pressure is below 10 cmH2O, most
apneas will be obstructive and you should put the
pressure up. There’s nothing magical about 10
cmH2O, it’s just a good place to put the line in the
sand.

Q.Can you over-treat apnea?

A.You can’t over-treat obstructive apnea. You
really don’t want the patient having unresolved
obstructive apneas. And we want not just to prevent
apnea - we also want to keep the airway sufficiently
open for the subject to breathe easily and regularly
and stay asleep.

But you can use too much pressure. The higher
the pressure, the greater the side effects. Although
this has never been proven, it is rather obvious - no
pressure, no side effects! So you want to use the
lowest pressure possible while keeping the airway
nicely open.

Q.Likewise can a device that responds to
hypopnea over-treat it ?

A.The funny thing is that it can both over-treat and
under-treat. It will put the pressure up through the
roof in some subjects, who have lots of central
hypopneas. And it can completely miss repetitive
severe silent inspiratory flow limitation that is totally
disturbing the patient’s sleep without there being
any hypopneas. If this occurs without CPAP, it is
called upper airway resistance syndrome. It is just
as bad for you as obstructive sleep apnea. But a
CPAP machine that responds only to hypopneas
will treat your obstructive sleep apnea, and give
you upper airway resistance syndrome instead.

Q.How can Automatic CPAP devices help
optimise treatment ?

A.CPAP devices, whether automatic or not, can
tell us - the clinician, the technician - about what is
going on when we are not there. Is the patient using
the device? Is there a leak, and if so, when and how
much? If it is an automatic device, what is the
pressure doing? How well is the patient breathing?
How steadily, how much? This might be particularly
important if the patient also has heart disease or
lung disease, or has had a stroke, and has other
reasons, apart from sleep apnea, for having
abnormal breathing during sleep.

Thanks for the detailed info!

Mindy

Yep, Avi, I appreicate this info very much as well. Except - I'm willing to bet 99 sleep specialists out of a 100 never look at those graphs and detailed data or even have the depth of knowledge of what those graphs are saying as explained in your quotes.

Just read through this whole thread and links!

An amazing thread so informative a truly enjoyable read.

So glad it surfaced again, otherwise I might never have seen it.