Wont Cpap always do better?

ok. Silly question. But arent i assured of having a higher AHI using apap as opposed to the best guess for cpap standard pressure, since the apap machine keeps the pressure lower UNTIL it has an event and then raises it and lowers it again, waits for the next event, etc? so, my ahi is 2.6 or so the past few nights. if i want it to zero, dont i just use cpap at my 90% or 90%+ pressure? i know each night is different and you can lose/gain weight, etc.. but if i just use apap to see if i have changed every month or two wont i get a better night sleep/sans arousals on cpap?

All depends ... different people respond differently to different things (including PAP treatment).

I use APAP mode set at 11 to 13 cm. My average AHI has been 0.4 for the last 11 months and I get zero AHI at least 2 or 3 times a week (hard for me to do better than that). I was able to optimize the pressure settings to a narrow range which gives me a safe lower pressure to cover all my events and a 2 cm cushion for those nights or sleeping positions when I need a little extra.

You won't know until you try it for yourself. Just remember that with APAP it is quite easy to set it to work as straight CPAP but you cannot make a CPAP work as an APAP.

i was titrated at 11--this eliminated most apneas--so i set mine from 11-13.5---my ahi for 3 months has been an average of---.6 keep the window tight and you will WIN----pat

I have the apap. just on cpap for a bit over a week. I can see how a tight range would indeed help.. But say you kept it at your max pressure, wouldnt you have zero? dont get me wrong, if i had 0.5 or 0.6 i would love apap. I know I have FAR TOO LITTLE data as of now to make any judgements. However, I am at best getting 2.5 or so and some nights a tad over 5.. i still get my best with a wide range, but will, after a month, tighten it.. still wonder how i am not guaranteed to have a 2.5 or 5 if i keep my min at a point where i know i get some apneas, etc.. even 2.5 sounds discouraging , as it means i arouse 20 times a night (much better than pr cpap when i did that in 30 minutes! )

Dreamstalker, what was your lab titrated pressure? i was at 9, but 9 kilss me on apap.. I am at a 90% of 11+.. seems 11 kilss most of it. i am much more stuffy at home with down and dustmights, etc. the hospital setting was sterile and i breathed better that night than ever. i also assume my congestion will require higher pressure to get through my nose?? wonder if that counts as a flow limitation. Dont get me wrong, i love apap for this reason and am beginning, after one week, to realize that 9 would have been a bad cpap level. i am tempted to do 9 at cpap for a week, but hate to give up a 2.5 ahi

neillebo wrote:Dreamstalker, what was your lab titrated pressure? i was at 9, but 9 kilss me on apap.. I am at a 90% of 11+.. seems 11 kilss most of it. i am much more stuffy at home with down and dustmights, etc. the hospital setting was sterile and i breathed better that night than ever. i also assume my congestion will require higher pressure to get through my nose?? wonder if that counts as a flow limitation. Dont get me wrong, i love apap for this reason and am beginning, after one week, to realize that 9 would have been a bad cpap level. i am tempted to do 9 at cpap for a week, but hate to give up a 2.5 ahi

I was titrated at 10 cm and was given a CPAP. A few days after starting treatment, I found this forum and learned how to take control of my treatment. I used the CPAP for about a month and managed to get a good AHI of about 3 or 4. At my request, I had my doc change me over to APAP and I was able to get AHI down to 1 or 2 w/ doctors Rx of 8 cm to 13 cm.

After 3 or 4 months of my own tweaking (with help from great members on this forum) I finally got it down to 0.4 with setting of 11 cm to 13 cm. Since Feb 07 it has been consistent at 0.4 AHI.

For me, the sleep lab's titration of 10 cm CPAP did OK and the doc's Rx of 8 cm to 13 cm APAP did better ... but the results of tweaking the APAP w/ help from this forum did the best.

When you consider that my AHI was 102 prior to treatment, one can argue that the difference between an AHI of 3 and one of 0.4 is insignificant. I will admit that I cannot tell the difference between AHI of 0.4 and 1 or 2 but above 2 and I can start to notice a difference in the quality of my sleep rest ... perhaps my body has adjusted (become addicted) to the new O2 levels?

Try updating your sleep environment to get rid of the down and dustmights, etc. ... and also consider a regular nasal saline irrigation for the congestion.

Best wishes.

neillebo wrote:since the apap machine keeps the pressure lower UNTIL it has an event and then raises it and lowers it again, waits for the next event, etc?

Well, I may be completely wrong in my understanding of how autopaps work, but I don't think an autopap waits UNTIL there's an event (apnea or hypopnea) and THEN raises the pressure.

I know a lot of doctors and DMEs say that...that a person has to HAVE an "event" before an autopap will raise the pressure. I think the machines work more proactively than that.

My understanding is that if an autopap sees a change in airflow that might indicate an event could happen (hasn't happened yet) the machine will start taking corrective action to PREVENT an "event" (apnea/hypopnea) from happening. Preventive. Not just "reactive."

Of course so much depends on a particular person's own form of obstructive apnea. Some can be hit hard by sudden closures if they turn on their back. Or are in REM. Or both conditions. Others might have a more gradual collapse of soft tissue no matter what.

I do think that for most people (not "all"...just "most) autopap therapy will go better and more smoothly if they set the minimum pressure up AT (or almost at) whatever pressure it takes to completely prevent obstructive apneas.

Then set the upper pressure however high you want to. What isn't needed up above won't be used, so for most people (again.."most" imho, not "all") it really doesn't matter how unnecessarily high you set it, as long as you set the max pressure up at least enough to let the machine handle events that need more pressure.

That will be using an autopap almost as if it were a cpap (minimum pressure being high enough to prevent most events from the get-go), but still giving room up top for more pressure to be used if needed.

Of course having the software -- EncoreViewer for Respironics machines; Silverlining for Puritan Bennett machines -- helps immensely in figuring out just where the minimum pressure can be set for most effectiveness and still be comfortable.

rested gal wrote:

neillebo wrote:since the apap machine keeps the pressure lower UNTIL it has an event and then raises it and lowers it again, waits for the next event, etc?

Well, I may be completely wrong in my understanding of how autopaps work, but I don't think an autopap waits UNTIL there's an event (apnea or hypopnea) and THEN raises the pressure.

I know a lot of doctors and DMEs say that...that a person has to HAVE an "event" before an autopap will raise the pressure. I think the machines work more proactively than that.

My understanding is that if an autopap sees a change in airflow that might indicate an event could happen (hasn't happened yet) the machine will start taking corrective action to PREVENT an "event" (apnea/hypopnea) from happening. Preventive. Not just "reactive."

Of course so much depends on a particular person's own form of obstructive apnea. Some can be hit hard by sudden closures if they turn on their back. Or are in REM. Or both conditions. Others might have a more gradual collapse of soft tissue no matter what.

I do think that for most people (not "all"...just "most) autopap therapy will go better and more smoothly if they set the minimum pressure up AT (or almost at) whatever pressure it takes to completely prevent obstructive apneas.

Then set the upper pressure however high you want to. What isn't needed up above won't be used, so for most people (again.."most" imho, not "all") it really doesn't matter how unnecessarily high you set it, as long as you set the max pressure up at least enough to let the machine handle events that need more pressure.

That will be using an autopap almost as if it were a cpap (minimum pressure being high enough to prevent most events from the get-go), but still giving room up top for more pressure to be used if needed.

Of course having the software -- EncoreViewer for Respironics machines; Silverlining for Puritan Bennett machines -- helps immensely in figuring out just where the minimum pressure can be set for most effectiveness and still be comfortable.

I'm going to disagree with RG. (to a degree)

These are sophisticated "contraptions" with sensors and programs that look for events and then make changes based on what it interprets. Even changes in airflow can be termed as "events" to the program (algorithm).

Algorithm

1. problem-solving procedure
a logical step-by-step procedure for solving a mathematical problem in a finite number of steps, often involving repetition of the same basic operation

2. problem-solving computer program
a logical sequence of steps for solving a problem, often written out as a flow chart, that can be translated into a computer program

I just re-reviewed the "Autoalgorithmtraining.exe" program that I downloaded a couple of years ago and every description that is explained in it points to "event detection" driving the reactions of the machine....raising pressure or lowering pressure. In other words, it has to "see" something happening. In some cases it averages a series of breaths to determine a trend, but that is still a function of the detection (sensors) and the program (algorithm).....and that would still be "reactive".

If you want a "preventive" machine......switch it to CPAP mode. (with the proper pressure)


Den

I would think that a CPAP, set to the correct pressure, that didn't trigger centrals, if you didn't have leaks, would produce the best results.

But we don't all do business in that make believe world. APAP, adds the relief of less pressure and leaks caused be using more pressure than needed. This can cause better compliance, and is the main reason APAP is used, besides the fact that you can use it as CPAP if wanted without needing to purchace another machine. More bases covered, more options for not much more in price. Jim

thanks all for the replies. I am encouraged to have a 2.5 for 2 of my first few days and will work over time on the tweak. Per my graphs it always tries to get my pressure back down to my min when it doesnt have any events.. then when it senses a reduction of sorts, it goes up a tad, but never enough to catch the hypopneas, etc.. it only goes up marginally. it also doesnt catch many flow limitations for that reason.. So, i think it does spike it a fraction on reduction, but often needs 1-3 more levels of pressure to stop it.. it also wont assume you are in rem, so wont just go from 7-10 in a few seconds.. My guess is that , as many have said, that it reacts a little, but mostly responds to the event. thanks for all. much much to learn!

Wulfman wrote:I'm going to disagree with RG. (to a degree)

LOL!! That's ok...I like to learn, and you're a good teacher.

Wulfman wrote:These are sophisticated "contraptions" with sensors and programs that look for events and then make changes based on what it interprets. Even changes in airflow can be termed as "events" to the program (algorithm).

I don't think we are in disagreement about what autopaps do (insofar as what a "black box" does can be understood.) I think it's more a matter of definitions.

I was using the word "events" to mean apneas and/or hypopneas. As in some doctors telling people, flatly..."You have to have an apnea first before an autopap will do anything."

Usually on this message board, when people are talking about "events", we are talking about apneas and hypopneas.

Wulfman wrote:I just re-reviewed the "Autoalgorithmtraining.exe" program that I downloaded a couple of years ago and every description that is explained in it points to "event detection" driving the reactions of the machine....raising pressure or lowering pressure. In other words, it has to "see" something happening.

I agree absolutely that the machine has to see something happening before it will make a change in what it's doing. Technically, sure, a slight change in flow is an "event." Algorithmically speaking.

But it's not yet an "event" -- message board speakingly -- meaning an apnea or hypopnea. And perhaps isn't even enough of a flow limitation YET to be marked as "flow limitation" on the software data.

Wulfman wrote:In some cases it averages a series of breaths to determine a trend, but that is still a function of the detection (sensors) and the program (algorithm).....and that would still be "reactive".

LOL, ok, ok. I understand what you're saying, algorithmically speaking.

Can we mesh the two definitions of "events" - the technical definition and the message board definition, and say this?
With the proper pressure settings, an autopap reacts to slight changes in airflow in order to proactively prevent apneas and hypopneas for most (not all) people?

Heck, if you don't like the word "most", I can go with "many." Or even with "some" people.

Wulfman wrote:If you want a "preventive" machine......switch it to CPAP mode. (with the proper pressure)

Den

Yep. Nothin' wrong with using a hammer all the time if you don't hit your thumb much.

I do agree with what you've written many times, Den -- that for some people CPAP (with the proper pressure) gives more effective treatment than autopap (with the proper settings.) I think the opposite can be true for others.

neillebo wrote:thanks all for the replies. I am encouraged to have a 2.5 for 2 of my first few days and will work over time on the tweak. Per my graphs it always tries to get my pressure back down to my min when it doesnt have any events.. then when it senses a reduction of sorts, it goes up a tad, but never enough to catch the hypopneas, etc.. it only goes up marginally. it also doesnt catch many flow limitations for that reason.. So, i think it does spike it a fraction on reduction, but often needs 1-3 more levels of pressure to stop it.. it also wont assume you are in rem, so wont just go from 7-10 in a few seconds.. My guess is that , as many have said, that it reacts a little, but mostly responds to the event. thanks for all. much much to learn!

APAP, does respond slowly to needs, that is the reason I control the range for me closely. I know I have centrals at 15 cm, it wouuld be foolish for me to set the top at over 15 cm., so I don't. I also set the low 3 or 4 cm below the top (CPAP) setting, that way it doesn't take as long to react to events.

CPAP will give me a lower AHI., but for comfort I am willing to put up with a MAX increase of less than 0.5 AHI. Normal for me is CPAP AHI 0.5 and APAP AHI 0.7, unless I change what I do. (OTC decongestants) Jim

Sometimes I take them out of my normal timing, and I pay the price with a bad night.

Did you learn of your centrals at 15 from your labl titration or from the machine? i get mixed feedback on here. It makes sense that a NR may indeed be a central. However, if you dont keep the pressure ABOVE where you get centrals then you can never get an NR, can you? My question is that if, lets say you are already at your max pressure and you get an apnea (could be central or obstructive), why would the machine say NR? isnt it possible that it will just call it an apnea.. In order to be NR doesnt it have to try 3 different times at higher pressure? if i am already on 11, for ex, and this is my max, and i have an apea, it wont even try to go above 11, thus wont try for 3 times, thus wont call it an NR and that APNEA might be a central, no?? again, i have debated with someone that didnt make sense to me.. so, is it not possible that you are getting centrals that register as apneas if you are already at max pressure? I got 4 centrals in lab at pressure of 9, but suspect it was just my body getting used to it all (and had a full face mask there)

rested gal wrote:Can we mesh the two definitions of "events" - the technical definition and the message board definition, and say this?

No problem! How about calling them "conditons"? (algorithmically speaking)

Since these things are run by computer programs, I have to look at it from a programming standpoint.
(Example) If THIS condition exists....do "B"....else, do "A".

They can only do (hopefully) what they're programmed to do (assuming the sensors are working properly)......algorithmically speaking, of course.

I've smashed my fingers with hammers......many, many times.

Best wishes,

Den

neillebo wrote:Did you learn of your centrals at 15 from your labl titration or from the machine? i get mixed feedback on here. It makes sense that a NR may indeed be a central. However, if you dont keep the pressure ABOVE where you get centrals then you can never get an NR, can you? My question is that if, lets say you are already at your max pressure and you get an apnea (could be central or obstructive), why would the machine say NR? isnt it possible that it will just call it an apnea.. In order to be NR doesnt it have to try 3 different times at higher pressure? if i am already on 11, for ex, and this is my max, and i have an apea, it wont even try to go above 11, thus wont try for 3 times, thus wont call it an NR and that APNEA might be a central, no?? again, i have debated with someone that didnt make sense to me.. so, is it not possible that you are getting centrals that register as apneas if you are already at max pressure? I got 4 centrals in lab at pressure of 9, but suspect it was just my body getting used to it all (and had a full face mask there)

In my quest for the best pressure, I kept increasing it a little 4 days at a time until my AHI started going up instead of down. After 15 cm my HI started up at a high rate, under 15 cm, every thing went back down. That's how I fine Tuned Mine until I got APAP. Then with APAP you have to play with a new toy, I got lost and confused about my pressure on APAP, learned the hard way changes must be made in small steps, and tested for a few days. I changed too many things too fast, and it caused me some false ideas. Now we are dialed in and good to go. Jim