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rhodesengr wrote:some new data with minimum pressure increased from 5 to 6.
Hard to be sure with only one night of good data but the AHI is a bit lower and the number of snore event appears to be statistically lower for sure. The spike in the flow rate was just me getting up for a bathroom break.
Some questions:
Is there a way to take the mask off without spiking the Leak data? I think if I turn it off, the session end. I guess I am looking for a Pause button.

What is the downside of too high a minimum pressure? Raising from 5 to 6 seem to improve things as suggested (you guys are great) so maybe I should go even higher. Are there negative effects if you go too high?

I turn mine off when I get up to go to the bathroom. The software is looking at a whole day, and a two or three minute break is not going to alter results in a significant way.

I started at fixed 6.0cm. Now I am up to Apap 17.0 - 20.0 cm. Other than what was already addressed about centrals, the only things I have to add are that some folks are uncomfortable with higher pressures. Fortunately it doesn't bother me. Also you are nowhere near the maximum. So it probably won't have any effect if you tweak it up a cm or two. The other side effect is I MAY be a little gassier than usual. But I am also trying to eat healthier, and the veggies may be to blame. LOL.

well the question is whether I should continue to go up like maybe 7cm

BTW, I really like the software. Its is quite intuitive. Features I went looking for like fixing the Y axis were right there and easy to find.

So I know I might be looking at the data in too much detail but I am trying to understand as much as possible. There is not much of anything remarkable in the data and my AHI seems decent. But I noticed a series of pressure spikes. I zoomed in on some and posted below. I tried to figure out what would be causing the machine to increase and them decrease the pressure. I wasn't sure which plots would reveal the casual event so I took my best guess. The only thing that is 100% correlated with the pressure spikes is the leak rate which has matching bumps for every pressure bump. I don't think that is casual though. I think the baseline leak would just increase due to the increase in pressure. So I don't see what triggers the machine to increase the pressure. Any ideas? Would different plots be more likely to show the cause?

The "saw tooth" pattern.
viewtopic/t80875/Respironics-APAP-press ... se-up.html
As to why it decides to do it at some times and not others....anyone's guess as we are never told exactly why.
The corresponding leak increase you see is simply a matter of the vent rate also increasing slightly.
Remember the higher the pressure the higher the vent rate and since Respironics machines include vent rate in the total leak reported...it's higher because of the pressure and it is to be expected and is a normal byproduct.

The pressure is NOT increasing because of the leak though. It's the other way around and it's normal and nothing to get worried about.

While this guide is for Encore software the basics for the data are the same no matter which software is used.
EncoreGuide link this will show you examples of what you will see. For a different machine than yours but the basics are the same.
http://www.healthcare.philips.com/pwc_h ... _Guide.pdf

SleepyHead is giving you the same data points as Encore would...SH just presents things visually a little differently.

rhodesengr wrote:well the question is whether I should continue to go up like maybe 7cm

BTW, I really like the software. Its is quite intuitive. Features I went looking for like fixing the Y axis were right there and easy to find.

So I know I might be looking at the data in too much detail but I am trying to understand as much as possible. There is not much of anything remarkable in the data and my AHI seems decent. But I noticed a series of pressure spikes. I zoomed in on some and posted below. I tried to figure out what would be causing the machine to increase and them decrease the pressure. I wasn't sure which plots would reveal the casual event so I took my best guess. The only thing that is 100% correlated with the pressure spikes is the leak rate which has matching bumps for every pressure bump. I don't think that is casual though. I think the baseline leak would just increase due to the increase in pressure. So I don't see what triggers the machine to increase the pressure. Any ideas? Would different plots be more likely to show the cause?

I have heard it said on here that the machine "pings" higher pressures. Whether it senses something it thinks is happening, or is trying to head something off, I don't know. I'm pretty new here, but from what I have gathered so far........if you have a rather large range set, like 6.0-20.0, and you look at the report and see the pressure wants to hang out at a higher level than your minimum for a large part of the night, that might need to be your new minimum. Likewise, if the pressure graph shows you pegged for a large period of time at your maximum setting, it might not be high enough.

For what it's worth, I would kill for a 1.61 AHI. LOL. If you feel adjusting it up to 7.0 will help you, adjust it up to 7.0. Give it a week and see what happens. It certainly isn't going to kill you.

Mudrock63 wrote:It certainly isn't going to kill you.

But you might.

Mudrock63 wrote:I would kill for a 1.61 AHI.

A word about chasing the elusive AHI in low numbers like 0.0 or the less than 1.0 goal.
There may come a point where no amount of pressure increases will reduce the AHI all that much but it most likely won't hurt anything to try a little more pressure to see what happens.
The 2 drawbacks are if the more pressure causes aerophagia to rear its ugly head or centrals popping up (which is relatively rare so risk is minimal).

Back when I was first doing this whole apap thing I came to realize that I needed a 10 cm minimum pressure to prevent some pretty ugly clustering of events during probable REM stage sleep where my OSA is worse and happens to need more pressure.
I was seeing AHI around 2.0 at my settings of 10 cm to 20 cm max with some excursions to around 16 to 18 for probable REM sleep time frame.

So I decided to try more minimum to see if I could reduce that AHI which was ranging from 1.0 to 2.0 neighborhood by increasing that minimum. So I spent a few weeks increasing the minimum in 0.5 cm increments (stayed at 1 week with each change so that I could make sure any changes I might see were not simply normal nightly variations) up to 13 cm minimum. What I found at 13 cm compared to 10 cm minimum was that it didn't really change anything all that much. My AHI was still running 1 to 2....so I decided not worth it and went back to 10 cm minimum.

I was fortunate in that the pressure changes didn't cause any serious issues with aerophagia or centrals...and I learned that sometimes "this is as good as you get".

So if you wish to try a little more minimum and see what affect it has on things then go ahead and give it a try.
That way you will learn something in the process...you may find that it helps or doesn't help but you will learn at least something.

Mudrock63 wrote:I have heard it said on here that the machine "pings" higher pressures. Whether it senses something it thinks is happening, or is trying to head something off, I don't know. I'm pretty new here, but from what I have gathered so far..

there's a slightly perverse aspect to the PRS1 auto algorithm. (in my opinion). when everything is calm, and going along perfectly, it starts poking at you, with those pressure increases... seeing if it can 'make things better'. effectively it's like having someone watching you sleep, and when you seem perfectly peaceful, they start poking you saying "how're you sleeping?" I've seen *very* minor disturbances in the flow patterns at the tops of those pokes, indicating that for some people, it causes a very minor disturbance in their sleep.

the perversity of it, to me, is that if you're NOT having a very calm, peaceful time, ie, if your sleep is showing up as disturbed, then it does NOTHING!!!! it doesn't try to see if a bit more pressure would make things better. it's like the test condition in the machines programming is backwards.

rhodesengr wrote: The only thing that is 100% correlated with the pressure spikes is the leak rate which has matching bumps for every pressure bump. I don't think that is casual though. I think the baseline leak would just increase due tsso the increase in pressure.

to expand a bit on what Pugsy said, if you look in the back of the booklet/information sheet that came with your mask (you can download a copy off the net if you lost the paper one) you'll find a chart, or graph, with expected leak rates at various pressures.

since the vent holes in the mask are fixed, what happens is that more air vents from them as the pressure goes up... typically it's around 20 liters per minute @ 4cm pressure, going to to around 50liters/minute @ 20cm pressure. each mask has a slightly different vent curve (also called intentional leak), but most of them are in that ballpark.

so when the pressure goes up, so does the total leak (the top line on the leak chart).

palerider wrote:so when the pressure goes up, so does the total leak (the top line on the leak chart).

Thats what I thought and what I meant when I said I didn't think the leak was causing the pressure; just increasing leak in proportion to the increased pressure.

rhodesengr wrote:

palerider wrote:so when the pressure goes up, so does the total leak (the top line on the leak chart).

Thats what I thought and what I meant when I said I didn't think the leak was causing the pressure; just increasing leak in proportion to the increased pressure.

yes, i was just attempting to confirm, and explain a bit about why it happens

ChicagoGranny wrote:

Mudrock63 wrote:It certainly isn't going to kill you.

But you might.

Mudrock63 wrote:I would kill for a 1.61 AHI.

Haha! I'm thrilled to see anyone get this problem under control. The lowest I've gotten is 5.0-8.0. Maybe I'm chasing the elusive 0.0. I feel good. But I want to feel great!!! Next step is Bipap, just waiting for my next appt.

palerider wrote:there's a slightly perverse aspect to the PRS1 auto algorithm. (in my opinion). when everything is calm, and going along perfectly, it starts poking at you, with those pressure increases... seeing if it can 'make things better'. effectively it's like having someone watching you sleep, and when you seem perfectly peaceful, they start poking you saying "how're you sleeping?" I've seen *very* minor disturbances in the flow patterns at the tops of those pokes, indicating that for some people, it causes a very minor disturbance in their sleep.

Tsk, tsk. I'm going to tell Den.

ChicagoGranny wrote:Tsk, tsk. I'm going to tell Den.

what's going on Granny? you should have a nice cup of cider and a lie down... you've been extra bitchy today.

palerider wrote:

ChicagoGranny wrote:Tsk, tsk. I'm going to tell Den.

what's going on Granny? you should have a nice cup of cider and a lie down... you've been extra bitchy today.

I guess you use the b-word when you are caught and have no reply. I'll have the cider standing up, and you should get back to riding your pail.

Now where is Den?

what are you guys talking about? I must have missed something. I tried 7cm last night, up from 6 and my AHI got a little worse. It went up to 2.2 from 1.6. Its just one night so I'll stick with 7 for a while. I also had the P10 a little looser and saw either some leaks or mouth breathes. The leak line was not nice and flat like posted above.