Need some help on settings please

[izzyb]

It dawned on me that I have an auto bipap machine which is not set on auto but straight EPAP and IPAP pressures of 11/16. Like many people I have not felt a big difference since beginning therapy, so I thought maybe I should take advantage of what I have and let the machine get it right. So I went throught the process of changing it to Auto Bi-level. The problem is I'm not sure what I am doing. I have a window that shows "Max IPAP", "Min EPAP" and "Max Pres Sup". The settings that were already in the Max IPAP and Min EPAP were my original Bi-Pap settings of 10/14. I don't know why that was ever entered anyway since I wasn't set up to use the Auto. Anyway I just want to make sure about this - should my Max IPAP be the lower pressure and the Min EPAP be the higher pressure, and based on my current settings of 11/16, what should I set these numbers at? And what is the "Max Pre Sup"? I don't ever remember reading anything about that one on the board. If anyone knows of a link to this information or can help me out, I would appreciate it.

[izzyb]

I forgot to add that I did change the settings last night to Max IPAP - 18 and Min EPAP 10 - but then I got worried that I got the numbers backwards. But today when I checked my data it showed on the 90% pressure screen that I used 16.5/14 with an AHI of 0.8. If I set it up right, it looks like it worked. I used both pressures higher than my straight bi-pap is set for (16/11) and my AHI is the lowest I can remember it being. Maybe I did it right.

[izzyb]

It's myself again. I found this during a search and I am confused

Hi,

The Bipap Auto when in Auto mode, will adjust Epap (exhale) & Ipap (Inhale) CMS independently. This means they can each be adjusted to different pressures as the machines monitors you during the night.

To prevent the machine going rogue, you set a Max Pressure Support which is the maximum the two (Epap & Ipap) can roam apart during the night. The minimum is by default 2 CMS (you can't change this).

8 CMS is a very big gap & one only to ever be entertained with expert advice.

The max any normal (non COPD patient) should seriously set Max Press Sup to is 4 CMS). As mentioned, any greater than 4 CMS should be done with expert assistance.

Good luck

DSM

I don't understand why we would have bi-pap pressures more than 4 CMS apart in the first place if it is dangerous for our pressures to be that far apart. If this Max Press Sup keeps our pressures that close together, then why set our EPAP and IPAP apart more than 4 in the first place? And if this setting keeps it from automatically giving us the pressure we need then are we not NOT getting the treatment we need? I don't know if I made any sense or not, but I am sleep apnea chanllenged so please forgive me.

[rested gal]

izzy, you did it right. Setting it for Max IPAP 18 / Min EPAP 10 were good.

About the "Max Press Sup" setting... I don't agree with the statements about that setting the poster you quoted came up with. But, I'm not anything in the health care field, nor is the poster.

My personal opinion... since your original bilevel prescription was for IPAP 14 / EPAP 10, and you want to change to autotitrating bilevel mode, I'd set the M BiPAP Auto this way if I were you:

auto bilevel (Auto-titrating bipap mode)
Max IPAP 20.0
The " 18 " you chose for that was fine. Unused pressure up above is simply that...UNused. So it doesn't matter what max IPAP you choose as long as it's high enough to provide some unused ceiling room above what IPAP the machine has to go to for you. You can easily see whether there is a nice margin of unused pressures up above when you look at your downloaded data.
Min EPAP 10.0
Max Press Sup 8.0
Bi-Flex Setting 3
Autoramp time 0:00
Mask Alert Feature OFF
Auto Off Feature OFF
Split Night Time - Off
Show AHI/Leak Feature ON
Patient Reminder OFF


Set that way, the machine will start each time using 12 for inhaling and 10 for exhaling. It always starts out by using only two cms more IPAP than what you set EPAP for.

It will vary the IPAP/EPAP pressures independently of each other, with the Max Press Sup setting controlling how much gap they can actually have between them while in use....the gap may be as much as 8 cms (can't ever be more than the difference between the IPAP/EPAP settings) and no less than 2 cms of gap while they each do their own thing.

EPAP is to prevent apneas. IPAP is to handle flow limitations, hypopneas, and snores.

You can think of EPAP as what prevents most full collapses (apneas) of the airway right from the start.

Think of IPAP as what prevents the partial collapses (flow limitations, hypopneas, snores) that could lead to full collapse.

If EPAP is set high enough, the EPAP pressure line on your data should stay pretty much steady. IPAP has the busier job usually, and may move quite a bit.

______________________________

Here are links to my explanation (as I understand it) of the Maximum Pressure Support setting -- like two dogs on a leash.

That setting is called "Max Press Sup" in the M series BiPAP Auto.
It's called "PS" in the older non-M series BiPAP Auto.
Same thing.

viewtopic.php?t=22099
Jul 14, 2007 subject: What is 'Max Press Sup'

viewtopic.php?t=15666
Dec 08, 2006 subject: Question for BiPap users - UPDATED 12/14/2006

[Snoredog]

That AHI of 0.8 is excellent.

[dsm]

I agree that the 0.8 was very good & that says a lot about your having a go.

Very good.

On the issue of gaps you don't really need to be concerned because the Bipap Auto in Auto ranging mode sets the gap. Max pressure support of 4 though, is a conservative setting while getting used to that mode of the machine - but, setting it to max of 8 is I guess is also ok allowing that the machine will never get to it. If it did I believe you would know about it.

DSM

[izzyb]

My personal opinion... since your original bilevel prescription was for IPAP 14 / EPAP 10, and you want to change to autotitrating bilevel mode, I'd set the M BiPAP Auto this way if I were you:

rested gal, the 14/10 setting was my original setting nearly two years ago when I started. My pressure is 16/11 now. I just thought it was weird that there were any settings on the auto at all since I was never set up to use it. So with my pressure being 16/11 do you still think my auto settings are good?(18/10)

Snore Dog, My max press sup was set on 4 and I didn't change it since I didn't know what it was for.

About the max press sup - I still don't understand the need for that and why you would want to keep the pressure gap from going higher if you needed that difference in the IPAP and EPAP. Aren't you stopping your pressure from going as high as it needs to go? For example, if I need a IPAP of 10 and an EPAP of 16 and the max press sup is set on 4, then how can I reach either of those pressures? I just may not get the idea of this at all. But if I get the right idea, then wouldn't you want the gap to be as large as possible? Oh, I just had a thought - does the inhalation get where it needs to be and then the exhalation will only go lower however much the max pres sup is? Say if I inhale at 16 and the max pres sup is 4, then my exhalation will not go lower than 12? Am I even close?

Autoramp time 0:00
Mask Alert Feature OFF
Auto Off Feature OFF

Why would you have these features OFF?

Set that way, the machine will start each time using 12 for inhaling and 10 for exhaling. It always starts out by using only two cms more IPAP than what you set EPAP for.

Why would it start so low when I need a higher pressure for inhaling? Does the pressure increase during each inhalation until it gets where it needs to be?

One last thing. I forgot to reset last night so these numbers are the average of the last two nights:

15.4/12.9 with an AHI of 0.7 (16.5/14 the first night on auto)

What I find odd is the slight decrease, but I woke up early this morning with a snore/growl (that's what I call it) in my throat. Not a good sign. I only do that when I fall asleep maybe in the afternoon (never at bedtime) without my mask. I also woke up with a headache, which I do rarely, if ever.

[Snoredog]

prior results look fine to me.

[izzyb]

Okay, I see it a little better...maybe. I used to think I was a fairly intelligent person, but this is kicking my butt. The bottom line is that the machine knows what it is doing. But I still don't know what to set that pressure support at. It seems like you are saying that 4 is better than 8. I never realized that the EPAP was so important. I never viewed exhalation as important as inhalation or that it was helping apneas. I guess I got that idea when I went from CPAP to BiPAP and the EPAP being lower made it seem unimportant.

Also, in this scenerio, are you describing a whole nights session or just one inhalation/exhalation? I mean, in the process, does the machine keep moving the pressure up during one breath to stop that particular event or does it have to keep trying with each event until it gets it right? If that is the case, then wouldn't we be having apneas until the machine gets it where it needs to be? And that would be assuming each event needed the same amount of pressure to stop it, but I don't imagine that is true.

And I really appreciate you guys taking time to explain this to me. I feel really dense. I learn better with diagrams. Guess you could say you have to "draw me a picture".

[rested gal]

LOL... izzyb, don't worry if you get lost trying to follow Snoredog's explanation. Even though I use that machine and understand its settings, the dawg's rambling explanations can be quite a sight to behold. That was a pretty convoluted maze to try to follow. But hey, I'm about to ramble quite a bit, too!

My edit on Dec 4: Looks like Snoredog went back and edited out the entire text of several of his posts in this thread, including the long "rambling" one.

rested gal, the 14/10 setting was my original setting nearly two years ago when I started. My pressure is 16/11 now. I just thought it was weird that there were any settings on the auto at all since I was never set up to use it. So with my pressure being 16/11 do you still think my auto settings are good?(18/10)

Yes. The settings you chose for using auto bilevel mode still sound fine. Only thing I'd change in how you set it is to put the max press sup setting at " 8 ."

I guess this next question was for Snoredog, since I agree with you, izzy... I do want the gap to be as large as possible.

About the max press sup - I still don't understand the need for that and why you would want to keep the pressure gap from going higher if you needed that difference in the IPAP and EPAP. Aren't you stopping your pressure from going as high as it needs to go? For example, if I need a IPAP of 10 and an EPAP of 16 and the max press sup is set on 4, then how can I reach either of those pressures? I just may not get the idea of this at all. But if I get the right idea, then wouldn't you want the gap to be as large as possible?

You probably made a typo in your question when you said, "if I need a IPAP of 10 and an EPAP of 16" .... Switch those words and yes, I think you do have the right idea, that a person would want the gap to be as large as possible.

The IPAP (inhale pressure) is the higher one. EPAP (exhale pressure) is the lower one. No bilevel machine will let you set IPAP lower than EPAP.

But back to your question:

About the max press sup - I still don't understand the need for that

Well, among other uses, the "max press sup" is a safety measure. A "leash" that keeps IPAP and EPAP from getting tooooooooooo far apart from each other. It might be very disrupting to sleep for many people if the following unlikely scenario happened...

Say that the machine was set pretty much "wide open", like EPAP 4 and IPAP 20. Say that EPAP was preventing apneas at that low pressure, but IPAP had to go all the way up to 20 to deal with flow limitations or snores.

You can imagine how it jolting it might feel to be breathing in at 20 and breathing out at 4. Better that IPAP start pulling EPAP up along with it at some point, just to keep EPAP within a reasonable distance (no more than 8 cms apart) of IPAP.

Oh, I just had a thought - does the inhalation get where it needs to be and then the exhalation will only go lower however much the max pres sup is? Say if I inhale at 16 and the max pres sup is 4, then my exhalation will not go lower than 12? Am I even close?

Yep...that's it. That's the way it would work for a machine set the way you set yours: max IPAP 18, min EPAP 10, max press sup 4. You got it!

The most important key, imho, to setting the bipap auto is:
Set the min EPAP high enough in the first place to do its one job well...high enough to prevent full apneas.

If you get the min EPAP set right, EPAP is likely to stay pretty much right on that one pressure all night long. Doing its one job. Warding off obstructive apneas.

Then, unless your doctor says otherwise, I'd set the "max press sup" to give as much leeway as possible for IPAP and EPAP to do their respective jobs as independently as possible of each other.

Think of MIN EPAP as an old slow dog plodding along on a steady line with only one job to do... to keep full apneas away.

The younger dog named MAX IPAP ranges out further ahead and is usually a lot more active. IPAP's job is to try to prevent the usually more frequent, lesser closures (flow limitations, hypopneas, snores) from developing into full apneas.

The two dogs (Min EPAP / Max IPAP) are connected to each other with a leash between them. The leash connecting old plodding EPAP and young active IPAP can be short (max press sup set at 3) to keep them close together, or long (max press sup set at so that IPAP has more room to range freely up ahead as needed without jerking old EPAP along. IPAP, which is almost always the more active of the pair, can do a lot of running up and down as needed, without jerking EPAP upward unnecessarily.

Why would you have these features OFF?

Regarding Autoramp, Mask Alert, Auto Off all being set to "OFF" in my suggested settings, you could set them any way you like. I'd definitely keep "Auto Off" turned off, even if I turned the first two on. I don't want the machine turning itself off while I'm asleep, which is what Auto Off "on" (enabled) can do in some situations.

I keep Autoramp turned off because I never use ramp on any machine. I like my therapy to start right from the get-go, and I have no difficulty at all falling asleep using the machine.

It always starts out by using only two cms more IPAP than what you set EPAP for.

Why would it start so low when I need a higher pressure for inhaling? Does the pressure increase during each inhalation until it gets where it needs to be?

No, the pressure doesn't increase during each inhalation.

In thinking "gets where it needs to be" you're thinking about your "simple bipap" prescribed pressures.

The two pressures (IPAP/EPAP) that were prescribed for you with plain bipap were found during your sleep study to take care of "worst case scenario." EPAP is pretty simple for them to find...it's the pressure that prevents full apneas. IPAP can take more "titrating" to knock out flow limitations, hypopneas, and snores.

Perhaps you needed "that much" IPAP only when you're in REM sleep or are sleeping on your back. Perhaps your throat stays nicely open most of the night at a lower IPAP pressure. That's the point of using "autotitration" -- to have the pressure vary "as needed" throughout the night. Using lower pressures when more isn't needed. And higher pressures when more is needed.

The most important pressure to set "right" on a bipap, imho, is the EPAP pressure. Called "min EPAP" when using autotitrating bilevel. EPAP (min EPAP) should be set high enough to prevent most apneas right from the start, imho.

Get min EPAP set right (high enough to prevent full apneas) and the min EPAP pressure line will pretty much stay steady all night long when using autotitrating bilevel mode.

IPAP is likely to move up/down quite a bit, but if you have EPAP where it should be and the "max press sup" setting opened up ( I set "max press sup" as wide as it will allow -- the full 8 cm ) the EPAP pressure may never have to go up at all, all night.

IPAP will do its thing, as needed...with a nice long leash to keep it from tugging unnecessarily at EPAP.

[jnk]

Thanks, rested gal.

Great explanation of how a Respironics autotitrating bilevel works!

[ozij]

Some picture here for you, Izzy.
http://bipapautomseries.respironics.com/
O.

[Snoredog]

prior results look fine to me.

[izzyb]

Thanks again for all the info.

I changed my max IPAP setting to 20 and left the min EPAP at 10 and left the PS at 4. These are my results from last night:

19.5/17.0
AHI 1.9
My leak rate was higher than it has ever been but I don't think it is too horrible - 42.8. It was 36.7 that first night which is good for my mask. I had a bad night. My mask was too loose and I was awakened by major leakage but corrected that. Didn't sleep well (well I never do, but it was worse last night).

What puzzles me is I went to 19.5. Now the first night it was 16.5. So what if I hadn't changed my setting to 20? Does that mean my regular, non-auto settings of 16/11 are too low and that I sometimes need more than 16. I obviously did last night. And is it because I was leaking more why it had to go so high? And wow - isn't 17 high for exhalation?

So much to learn.

[Snoredog]

prior results look fine to me.