Leak Rate maybe Skewing AHI ?

[StratCat48]

In another thread I posted a couple of OSCAR graphs to compare a DreamStation 2 to an AutoSense 10. It was noted the graphs indicated a high Leak Rate. Looking at the DreamMapper data for the DS2 for the day of the graph, it did show a Mask Fit of 93%, Large Leak Time of 0.31hrs, % of Night in Large Leak 7.1%. Most typical nights DreamMapper shows Mask Fit 100%, 0 hrs large leak time, and 0% night in large leak.
For the AS10 on the date of that graph the Mask Seal was 34(Leak)L/min. per Resmed myAir with OSCAR showing an of AHI 0.11
Graphs in the other thread are at https://www.apneaboard.com/forums/Thread...#pid533464

Below are posted a DS2 OSCAR graph and a screenshot of DreamMapper for the same night. The DreamMapper App would suggest no problems with leaks. Would DreamMapper be incorrect in regards to the data OSCAR shows. DreamMapper typically does show good mask fit like the one shown below.
To note, I am using a FF mask, an F&P Vitera which to me seems to blow a good amount of air through its vent (enough to wake the wife if towards her). Not sure if vent loss could account as leakage(?)

[Deborah K.]

Your leak rates look high, but on a Dreamstation it is hard to tell. I think yours is low enough to not worry about. Can you tell if your mask is leaking? Venting doesn't count. Do you feel leaks around the edge of your mask? If not you're okay and don't need to worry.

[Jay51]

PR machines report total leaks (intentional leaks + unintentional leaks).  

Also, unintentional leaks = total leaks - intentional leaks.  

Hence the 2 separate lines on the leak chart.  

Total leaks is the top line.  

Resmed is at 24L/min.  

OSCAR only reports what the machine says.

[mcgravy]

I run high pressures. Bipap. Like 15 to 20. I use a Full face Simplus mask. But I also use mask liners and they really solved my leaks. Remmzzs I think they're called. My machine needs at least a 85% mask fit to sense properly. So you may get skewed results.

[Deborah K.]

So, Jay, am I right that his leaks are not enough to interfere with therapy?

[Jay51]

Yes, Deborah, that is what I am seeing based on what is reported.  But, just like mcgravy said, the leak data could very well be skewed; and thus skewing other relevant data also.