Leaks with the Air Curve VAUTO

[Walla Walla]

Here's some background. I was using a Dreamstation AUTO Bipap and switched to a ResMed VAUTO 3 days ago.

With both I was using a P10 mask. I do suffer from mouth leaks but never had a big problem crossing the red line on Sleepyhead. Now on the VAUTO I'm above the redline a lot.

The thing that caught my attention was the bottom leak rate for the DreamStation was around 1 or 2 % and on the VAUTO it seems to run around 14%

It appears the ResMed VAUTO is adding on a 12% leak rate to what was reported by the Dreamstation.

First chart is the DreamStation. Second Chart is the VAUTO. 

Also I noticed a Tidal Volume difference of about 60.

Question is what to make of the base leak rate difference?  

[Walla Walla]

[Whacked]

Hopefully someone with more knowledge will chime in, I'm interested too.

sure it isnt mouth leaks? Thats how I pop the top and get into large leak territory. it usually wakes me up so thats how I know.

[TBMx]

just out of curiosity - what values for your intentional leak rate did you put into SH?

[Walla Walla]

Whacked,
I do have mouth leaks but I was looking at the bottom leak rate in the flow charts. If you look at the Dreamstation it starts out a zero. VAUTO starts out at 20cm leak rate.

TBMx,
I didn't put any intentional leak rate into sleepyhead. That's programed by the machines. However I do believe I might of found part of the answer. It has to do with the mask settings in ResMed machines.

Of course the answers were here on this board all along. See robysue's answers in this thread

http://www.apneaboard.com/forums/Thread-...alculation

Thanks robysue!

[TBMx]

philips does not care for your intentional leakage - in SH in the options you can however provide these values, which than make up the 2nd lower leak-curve.
I was only interested if you changed that because SH uses a linear function from 4 and 20cmH2O - which undershoots between these two but overshoots in your range.
As the leakrate with your philips looked "natural" I was a bit astonished. (that resmed is unable to estimate the intentional leak fo the P10 is nothing new - no clue what they are trying to do there)

[Walla Walla]

TBX, Thanks for the info. I didn't know about the P10 and Resmed. Would changing the mask settings to say an F20 make the leaks rates read closer to the Dreamstation?

[Sleeprider]

You have pretty high pressures, other than that we use similar settings.  Sleepyhead displays the unintentional leak line using the calculation set in file/preferences/CPAP  You might want to check the range being used there.  In addition, for non-Philips masks your mask resistance setting in the BiPAP would be zero, and that may affect what you see.  Still, on my Aircurve 10 Vauto, the base unintentional leak line is near zero, and yours is closer to 20 as you said.  That's suspicious and I don't think all of that is leak. I am assuming you did not open up the P10 vents or alter the mask?

[Walla Walla]

Sleeprider,
Nope masts are normal. In fact I switched out P10's just to check. But the Aircurve was still reading high right off the bat. The

DreamStation mask setting was 0 and/or off.

SleepyHead settings were: 4cm 20.1 L/min
20cm 48.3 L/min

P10 Spec's: 4cm 20 L/min
20cm 49 L/min
Almost the same.

I used the Dream station last night and it still reads the same on leaks.

I think the problem is with the Air Curve but I don't know if there's a fix.
I'll try switching the mask settings on the Air Curve tonight just to see what happens.

[Sleeprider]

Since your therapy is not compromised you could just set the flag in Sleepyhead at 46 L/min and give it the 20 L/min head start that appears to be the error.