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What makes pressure go up like this?
#1
What makes pressure go up like this?
Fairly often I see the pressure climb on my Airsense 10 for no apparent reason that I can suss out. Last night, as seen in the attachment, the pressure started climbing around 02:54 to the preset maximum of 10cm, then came back down. I was asleep the entire time and it didn't wake me; I just noticed it in the data this morning. I'm not seeing anything in the previous hour that would have caused it, unless it was something down in the weeds of flow limitation. Any insight into why these occur?

[attachment=10966]
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#2
RE: What makes pressure go up like this?
Don’t the pressure increases correspond to flow limitation according to the graph you posted?
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#3
RE: What makes pressure go up like this?
In that chart your settings should be 6-10 EPR 2. 6 to allow the EPR to fully function.
Recommended settings 7-10 EPR 3 to try to better manage your flow limitations.

Your pressure increases are caused by flow limitations.
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#4
RE: What makes pressure go up like this?
(03-24-2019, 11:55 AM)bonjour Wrote: In that chart your settings should be 6-10 EPR 2.  6 to allow the EPR to fully function.
Recommended settings 7-10 EPR 3 to try to better manage your flow limitations.

Your pressure increases are caused by flow limitations.

Interesting, thanks. I've been experimenting with different pressure ranges. Increasing the bottom limit of the pressure range helps EPR?
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#5
RE: What makes pressure go up like this?
by giving room for the EPR from the start so it will be most effective as PS for treating flow limits and hypopneas.  Note that min = EPR + 4.
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#6
RE: What makes pressure go up like this?
(03-24-2019, 12:23 PM)bonjour Wrote: by giving room for the EPR from the start so it will be most effective as PS for treating flow limits and hypopneas.  Note that min = EPR + 4.

Thanks. I made the suggested changes (pressure -> 7-10cm, EPR -> 3). It may be risky to draw conclusions from one night, since events like CA's and hypopneas vary from night to night, but see attached for the report from last night with the new settings.

[attachment=10971]

It seems as though there is no visible flow limitation at the beginning of the night when pressure is at 4cm, but begins when the pressure comes up to 7cm -- which apparently causes the pressure to then keep going up to the max of 10cm. With pressure at that level, there are then a couple of leaks, the second of which wakes me up around 2:20 am to adjust the gear. The CA's and hypopneas are actually quite low for most of the night, but then in the final hour or so they go up a lot -- a common pattern for me on many nights.

Just as another point of information, I remember that my HMO initially set the machine up with pressure as 4-20cm and EPR 3. Sleeprider made the suggestion early on:

Quote:With settings of 4-20 and EPR at 3, we see median pressure at 6.5 and 95% pressure of about 12 cm.  There is a strong positional apnea signal. While central apnea are being recorded, it is not a problem.  My suggestion would be a pressure rannge of 6 to 12 with EPR turned down to 2.


That's why the EPR was at 2. As far as pressure goes, I'm probably more sensitive to it than most PAP users, so at this point would like to bring it down a bit to 6-10cm. I'm definitely open to suggestions on what if anything to do at this point with the EPR. Thanks much!
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#7
RE: What makes pressure go up like this?
There's nothing inherently wrong with tinkering, provided you keep accurate records and that you don't attribute a single night's measurements to 'The Gospel According to Your Machine.'  

Due to nightly variance, which we all encounter when we look at the data, one should not use a single night to assume the changes are veridical.  To put it plainly, they may actually be entirely spurious...unless...you see a narrow range of variance following and the average adjusted change reflecting something consistent over time...maybe four or five days at least.

But, you must also keep scrupulous records so that you can recall what you altered, when you altered it, and by what amount.  Merely tinkering, with no method or with poor recall, is likely to lead to frustration, self-doubt, and perhaps failure.

As for the EPR, it can be whatever works reliably over several nights and weeks, provided there is enough range between the Min and Max pressures to begin with.  You can't have EPR 4 with a min pressure of 8 and high of 11, for example, which I would guess you understand.  My main point is, go ahead and find the sweet spot for you and your machine, but do not forget to note any changes, and to what.  Then, go at least four consecutive nights to see where you stabilize, or even IF you stabilize.
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