Here's today's detailed data:
Note that just like on the previous data the mysterious red curve is strictly between the purple IPAP curve and the green EPAP curve.
So I don't think that red curve can be the
average IPAP over a 2 minute window because the red curve is always
well below the minimum parts of the IPAP curve itself. And the
average anything can't be below the
minimum anything. Averages just don't work that way.
But I'm beginning to suspect that the red curve is the
average overall mask pressure over a 2 minute window or some similar window. In other words, I think this curve is averaging my EPAP values (accumulated over my exhales) combined with my IPAP values (accumulated over my inhales) combined with the transition times between IPAP and EPAP for some fixed time interval.
Now I know that red curve has nothing to do with Bi-Flex since since I don't have BiFlex turned on. So the pressure is suppose to simply drop to EPAP as soon as I start exhaling and it's
not supposed to start increasing the pressure to IPAP until the machine detects the beginning of an inhalation. I do have RiseTime set to 3, which means that the transition from EPAP to IPAP is as slow as the machine is willing to do it. (I'm not looking up the specs right now. Once upon a time I knew them by heart.)
For what it's worth, I compared my PR Dreamstaion Auto BiPAP data to my husband's PR System One Series 60 APAP machine. Here's his detailed data from last night:
Note: Hubby has A-Flex set to 3. And his pressure data includes only two curves: A purple curve, which is his therapeutic pressure setting and a green curve, which shows the affect of A-Flex, albeit not with anywhere near the detail that a Resmed "Mask Pressure" curve would show the affect of EPR.
So whatever OSCAR is doing to create that red curve from my Auto BiPAP data, it's not doing the same thing with my husband's APAP data.
Some final observations that have nothing to do with my red curve, but are relevant for folks interested in EPR vs. A-Flex/C-Flex, which used to be a very hot topic around here:
PR's A-Flex setting is PR's "exhalation relief" for their APAP machines. It's (vaguely) similar to Resmed's EPR in that it reduces pressure on exhalation, but it's quite a bit different from EPR in how much it reduces the pressure and how & when it starts to increase the pressure back up.
One of the big differences between EPR and A-Flex/C-Flex is this: EPR reduces the pressure by exactly the same amount on every exhalation. But A-Flex/C-Flex reduce the pressure by a
variable amount. That shows up in my husband's green curve: It's more raggedy than the red curve and the green curve is not always the same vertical distance below the red curve, albeit it doesn't vary all that much.
Another difference between EPR and A-Flex/C-Flex is that EPR reduces the pressure by a specified amount: EPR = 3 means the pressure goes down by 3 cm on each and every exhalation.
That's not what happens with A-Flex set to 3, at least not for my husband. Here's a zoomed in shot with a better y-range for showing the difference between the therapeutic setting (top curve) and what's going on with A-Flex:
First note that for the most part, hubby is getting about a 2 cm reduction in pressure when he exhales, not a 3 cm reduction. Second, note that there are places where the reduction is visibly a bit less than average and a bit more than average because even in the zoomed in shot, the two curves are not equidistant.
Joined as robysue on 9/18/10. Forgot my password & the email I used was on a machine that has long since died & gone to computer heaven.
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