Leak graph question

[accrn]

Good morning all!
I tried a new mask last night (the Brevida) and it just did not work for me. I finally switched back to the P10 just after 6 am. Why does the P10 show two leak lines and the Brevida only shows one? I *think* my machine reports the intentional leak PLUS any other unintentional leaks, but if this is the case, why do some masks have two lines and some do not? Does that mean the intentional leak is so low on the graph that if I don't have any large leaks the second line won't show up?

SH 2.2.19.PNG (83.01 KiB) Viewed 368 times

[Pugsy]

If you don't see that bottom leak line it's because it is on the 0.0 line and you just can't see it.
It's there but not visible.

[accrn]

If you don't see that bottom leak line it's because it is on the 0.0 line and you just can't see it.
It's there but not visible.

Thank you! I suspected that. But that leads me to another question... Why does the P10 show such an increase in leak over the Brevida? The Brevida was leaking like crazy, that's what kept waking me up. And in the short time that I wore the P10, I didn't have any leaks, especially in that first hour when I was trying to go back to sleep.

[Pugsy]

It's probably just a miscalculation in the vent rate showing more excess leak with one mask over another.
The machine doesn't know exactly which mask you are using and all masks have slightly different vent rates at whatever pressure is being used. The machine takes sort of an average at the beginning of the night when it assumes no leak is going on and bases calculations starting at that baseline for the rest of the night factoring in pressure changes. This was what I was told some years ago by a Respironics software technician as to how leaks were calculated.

So it gets close with the excess leak and total leak...but probably not an exact science since it can't allow for minor differences in vent rates between masks even between one pillow mask to another pillow mask.

I wouldn't worry about it. It is what it is and nothing you can do about it anyway. These very minor difference won't impact therapy.

[accrn]

It's probably just a miscalculation in the vent rate showing more excess leak with one mask over another.
The machine doesn't know exactly which mask you are using and all masks have slightly different vent rates at whatever pressure is being used. The machine takes sort of an average at the beginning of the night when it assumes no leak is going on and bases calculations starting at that baseline for the rest of the night factoring in pressure changes. This was what I was told some years ago by a Respironics software technician as to how leaks were calculated.

So it gets close with the excess leak and total leak...but probably not an exact science since it can't allow for minor differences in vent rates between masks even between one pillow mask to another pillow mask.

I wouldn't worry about it. It is what it is and nothing you can do about it anyway. These very minor difference won't impact therapy.

That makes perfect sense. As always you have a way of explaining all of this that I can so easily understand! I really appreciate the time you take to help.