Initial settings on BiPAP

I'll be receiving a Respironics BiPAP Auto with BiFlex this week. I have been using the Respironics Auto, which is a fine device, and am familiar with how to set the pressure on that (I'm using 14/16 currently).

It seems obvious how to set the inhalation number on BiPAP. What I'd like to know is how you determined your exhalation pressure initially. Did you start really low, which for me would be 8 or so, or did you start at (inhalation pressure minus 3) or suchlike?

Thanks.

In my case, I was supposed to start at 4-20 cm, based on my initial prescription (obtained from my primary care doc before my titration study was evaluated). However, the DME accidently set it instead for 10-20 cm, which probably made it much easier for me to adjust. I find a pressure of 4 way too low for comfort.

I have tweaked the settings based my EncorePro and MyEncore data (with the approval of my primary care doc, who has been very helpful).

Do you have a bilevel prescription? If so, it should give you some starting numbers for both inhale and exhale. If the prescription says 12/17, then set your exhale for 12 and your inhale for 17. (You read the bipap prescription differently than an auto prescription. An auto prescription that says 12/17 would be for a minimum of 12 and a maximum of 17.)

When using the Auto Bipap in auto bipap or auto biflex mode, your MINIMUM inhale pressure will equal your minimum exhale pressure plus 2 cm. You won't set the actual minimum inhale like you do on a regular autopap, just the MAX. inhale. The difference between inhale and exhale pressures ranges from 2 to 8, unless you set the top lower than 8. This setting is called "pressure support."

If your doctor doesn't tell you what settings to start with, based on your history of 14/16 autopap, I think your closest equivalent would be 12 min. exhale/16 max. inhale.

However, you are probably getting an auto bipap for some specific reason? So do you WANT equivalent pressures or do you want a change for some reason?

As always, just my own personal, non-medical opinion, take it or leave it,
Moogy

Thanks, Moogy, that was pretty much exactly what I wanted to know, although input from others is welcome.

You asked about prescriptions: although I had a sleep study which was read by a sleep specialist physician, I am getting treatment authorized by my general practitioner. As long as I make a reasonable case (which I can only do because of the people on this forum), he has been very accommodating. I think he knows I prefer an active role in my treatment, and seems to be okay in facilitating that. If my treatment were not going as well as it is, I would retain the local senior board-certified specialist.

Why I am going to BiPAP: the data from MyEncore suggests that there may be a best pressure above my current 15. I think that may call for an Activa and a BiPAP. Even if that turns out not to be the case, I have heard enough positive input about comfort and lower AHI with this device from people on this forum whose opinions I credit highly that I thought it was worth trying. I'll have the Auto as a backup.

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CPAPopedia Keywords Contained In This Post (Click For Definition): bipap, activa, AHI, auto

cwsanfor wrote: Why I am going to BiPAP: the data from MyEncore suggests that there may be a best pressure above my current 15. I think that may call for an Activa and a BiPAP. Even if that turns out not to be the case, I have heard enough positive input about comfort and lower AHI with this device from people on this forum whose opinions I credit highly that I thought it was worth trying. I'll have the Auto as a backup.

In that case, I would recommend 12 min. exhale, 18 maximum inhale, and watch the data.

Check to be sure your version of MyEncore will work with the Auto Bipap. I am running 1.5B7

Moogy

In a set of tests I did recently (in cooperation with SWS & Frequenseeker) I produced sets of figures showing that with a gap of 3 cms between exhale & inhale, I had my AHI down to 2.5 & lower.

Previously I had set the gap to 7 cms (8 / 15) and was consistently scoring AHI above 40 ! (yes 40).


The more I lowered the gap, the lower the AHI score dropped.

I then ran a weeks test in straight cpap starting at 10 & going up 1 cms per night. The cms that registered the lowest AHI score was 13.

Then I tried 10/13 & kept the AHI score low. Guess what I now stick to

I have no idea if this is what others will experience as I am in little doubt we all differ. But I am now also a believer that fluctuating pressures such as a big gap in Bilevel ipap/epap & from some other data, a low & high Auto cms (esp 4 /20), will cause many people problems.

The great thing about the current generation of machines is being able to extract the data and do comparisons.

Good luck with your machine.

DSM

Thanks Moogy and dsm. I'm probably going to sort of split the difference between your suggestions and start with 13.0 EP and 17.0 IP. That way, neither of you can reasonably be offended, and that setting seems to be analogous to my APAP settings: just a bit higher than my current "IP" and a bit lower than my current "EP", although I realize that is a sort of mixed metaphor. I like to make fairly small incremental changes when I can, and to vary one parameter at a time. Does that make sense?

I should have asked in a prior post, but what is your opinion on Maximum Pressure Support, and Rise in my scenario?

The device just arrived, and I'm planning to be prudent, and study the matter until tomorrow, but somehow I doubt that will happen. Upon reflection, I really should do one night with the current HC431 before switching to the Activa (arriving tomorrow), to provide some continuity <g>.

I'll post how it goes here.

cwsanfor wrote:Why I am going to BiPAP: the data from MyEncore suggests that there may be a best pressure above my current 15.

Y'know, your sleep study results (from your link) also suggests that your pressure requirement might be more than 15 cmH2O.

Your OSA is clearly quite positional. See how when you turned from supine to left at about 0130? Even though the pressure stayed the same (looks to be 10 cmH2O) the desaturations and hyponeas essentially disappeared.

Unfortunately, there was no return to supine to insure that the "ideal" pressure was in fact, just that. Which kinda leads into the APAP readings (guessing that you're spending at least some time on your back).

Also of interest is that in the diagnostic portion of the study, there are more central and mixed apneas (56) than obstructive (53).

Might be too soon for that thread, tho.
SAG

The Remstar AutoBipap uses the identical algorithm as the Remstar Auto, so you should expect similar response but have more flexiblity with EPAP pressure settings.

Moogy is the one to follow on that machine, but I would set your Min. pressure high enough that you are not starving for air (if your IPAP is now 15cm, I wouldn't start it any lower than about 7cm).

I would definately NOT leave it at the default minimum 4cm setting.

SAG,

Very interesting. Can you unpack that into details of what your observations would imply in my case- how your observations would affect my course of treatment in general or my upcoming Bi-PAP settings in paticular? Feel free to PM.

Thanks.

StillAnotherGuest wrote:

cwsanfor wrote:Why I am going to BiPAP: the data from MyEncore suggests that there may be a best pressure above my current 15.

Y'know, your sleep study results (from your link) also suggests that your pressure requirement might be more than 15 cmH2O.

Your OSA is clearly quite positional. See how when you turned from supine to left at about 0130? Even though the pressure stayed the same (looks to be 10 cmH2O) the desaturations and hyponeas essentially disappeared.

Unfortunately, there was no return to supine to insure that the "ideal" pressure was in fact, just that. Which kinda leads into the APAP readings (guessing that you're spending at least some time on your back).

Also of interest is that in the diagnostic portion of the study, there are more central and mixed apneas (56) than obstructive (53).

Might be too soon for that thread, tho.
SAG

Actually, I see the ideal pressure being at 14cm (looking at original titration, EncorePro and MyEncore reports. MyEncore shows the dip in pressure more clearly. If the patient is at risk of CA and machine is triggering any of those CA events more events would be seen with increased pressure (as seen on MyEncore chart).

If it were me, I would LIMIT the current machine Max. pressure to 14.0cm and forget about anything seen above that pressure from the reports. Because without EEG information to truly see what those events are, you would only be guessing.

Snoredog wrote:Because without EEG information to truly see what those events are, you would only be guessing.

Right, the best answer is to check the titration with NPSG, and for 2 good reasons:

First, those desaturations while supine are pretty nasty, and it sure would be nice to know if they are being properly addressed (yeah I know, oximeter, Procomm, and a piece of wire, but that's soooo lo-tech); and second, that many central and mixed apneas should at least alert you that CSBD could be underfoot. But while there is no real evidence in the available data (centrals didn't start coming out of the woodwork when the CPAP went up), fiddling with the BiPAP might be another issue. BTW, it looks like the definition of CSBD is going to end up to be something like "residual central apnea index of >5 with treatment", so right now, you ain't it.

However, as a thought, you might want to consider two separate strategies to address OSA. See how the machine responds to your position. Without NPSG tho, it's tough to do without a SO who isn't an insomniac.

But if the goal of BiPAP is to address apneas with EPAP and hypopneas with IPAP, then lateral settings should end up at about 13/7. Based on the limited data about supine CPAP, it would seem that the settings would be about 17 IPAP (based on the APAP results) but the EPAP could be anywhere because in that little bit of supine CPAP I don't see any REM.

cwsanfor wrote:Feel free to PM.

Yeah, they don't allow me to PM. Can't post links anymore either. Probably being punished for the vaseline thing. Hmmm, I wonder if images still post...
SAG

Let's see....

[img]No,%20you%20can't%20post%20images%20either,%20they're%20still%20links[/img]

Hmmm, this is a revolting development.
SAG

StillAnotherGuest wrote:

Snoredog wrote:Because without EEG information to truly see what those events are, you would only be guessing.

Right, the best answer is to check the titration with NPSG, and for 2 good reasons:

First, those desaturations while supine are pretty nasty, and it sure would be nice to know if they are being properly addressed (yeah I know, oximeter, Procomm, and a piece of wire, but that's soooo lo-tech); and second, that many central and mixed apneas should at least alert you that CSBD could be underfoot. But while there is no real evidence in the available data (centrals didn't start coming out of the woodwork when the CPAP went up), fiddling with the BiPAP might be another issue. BTW, it looks like the definition of CSBD is going to end up to be something like "residual central apnea index of >5 with treatment", so right now, you ain't it.

However, as a thought, you might want to consider two separate strategies to address OSA. See how the machine responds to your position. Without NPSG tho, it's tough to do without a SO who isn't an insomniac.

But if the goal of BiPAP is to address apneas with EPAP and hypopneas with IPAP, then lateral settings should end up at about 13/7. Based on the limited data about supine CPAP, it would seem that the settings would be about 17 IPAP (based on the APAP results) but the EPAP could be anywhere because in that little bit of supine CPAP I don't see any REM.

I did notice all those centrals and that desat, but I never saw the MD who read my chart to ask him about that. I've had no luck getting Sleepydave to look at my chart (at another site). My plan is to:

1) Get an oximeter for Christmas,
2) Try to schedule just a reading session with the local senior board certified sleep doctor,
3) Failing (2) above, get a repeat PPSG with said doctor at my one year anniversary,
4) See about eliminating supine sleep.
5) Lose 60 pounds by my one year anniversary,
6) Use a video camera to correlate my sleeping position with my chart.

I feel pretty good, have good numbers (AHI was 89 at PPSG, now 1-2), had a <decline> in centrals with increasing pressure during my titration, and register zero NR's with EncorePro. So I think I'm reasonably safe to accumulate some data with the BiPAP and see what happens.

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CPAPopedia Keywords Contained In This Post (Click For Definition): bipap, video, Titration, CPAP, APAP

OK, sounds like a great plan.

There is that other dial, Pressure Support. Now, in your case, the apneas disappear at low level CPAP (but again, only a little therapeutic supine, and no REM therapeutic supine). In order to take full advantage of the lowest effective pressure approach, you have to set the PS to maximum, and let the AutoBiPAP do it's thing. For argument's sake, let's say the lateral pressure does end up to be 13/7 and the REM is like 17/10. If you only use a MaxPS of 3 cmH2O, then you'll probably end up spending a lot of time at 13/10 lateral and 17/14 supine, because the IPAP will drag the EPAP up along with it.

Course, large pressure gradients also increase ventilation, and that can be the CSBD trigger/perpetuator. But I think we're starting to drift a little more away from that. The centrals and mixed apneas disappeared during basic CPAP (instead of getting worse), and if there's no NR events in the BiPAP approach (yet) then the case is starting to get a little stronger. And also, quite significantly, your diagnostic REM showed terrific desaturating events. This is somewhat contrary to CSBD, since REM tends to be more stabilizing.

However, Respironics technology doesn't say "here's a central apnea" like PB technology, they say "well, this don't respond, it's NR" (ya THINK?) and then you have to figure out what the mechanism could be. And it's not "what" it is, it's "when" it is. And you're at the pressure where all the NR rules kick in.

I also wonder if you don't see NRAs on APAP because the pressure you're at and the max APAP you've set don't allow an NRA to be scored. 9/9/2006 looks nice, but you've only got about 6 days in there that look good. My vote in the pool? Those are 100% lateral nights.

The diagnostic NPSG may be a case of the centrals and mixed apneas being obstructive, and perhaps the belts didn't quite pick them up clearly. And/or they just pushed the autoscore button. I wonder what software they used.

Anyway, as we move away from CSBD, you can afford to go a little crazy with PS.

The question for your guy remains "Wow, that is some bitter supine REM apnea in the diagnostic. How can you tell what the effective therapeutic pressure for that is?" But perhaps he considered that. In looking at the titration alone, the effective pressure should have been 12 cmH2O, there were only 3 events in 109 minutes of sleep, for an AHI of about 1.65. Oh yeah, the desat to 83%. But it's so out of the blue, you wonder if it could be artifact.

But to continue the wishy-washy waxing and waning (oooh, new shortcut for non-committal-- "W4"), the desaturation line never really looks completely stable in REM titration. Which really screams the question, "What happens in supine REM?"

And why the meandering ends up with

the best answer is to check the titration with NPSG

SAG

StillAnotherGuest wrote:Let's see....

[img]No,%20you%20can't%20post%20images%20either,%20they're%20still%20links[/img]

Hmmm, this is a revolting development.
SAG

Ratzzzz. Gotta have links from SAG!

Register that cool nickname, so you can continue linking the great graphs and stuff you have provided in other threads!! Just do it!! LOL!!

I went back to the ASV thread to see if previous pics you posted were still there...whew...they are.