what's an acceptable leak rate?

rested gal wrote:

taberge wrote:Read your manual for your mask. There should be included information that gives you the acceptable leak rate at a given pressure setting.

That's true if a person is using a Respironics machine like the Respironics M series machine your equipment profile shows, taberge.

But for those using a ResMed machine (as robysue is) ResMed accounts for the expected acceptable leak rate (from the mask vent) when the person chooses the correct "mask setting" on the machine for the mask they are using. Ideal leak rate for a ResMed machine (since the acceptable leak rate is already subtracted) is 0.0.

Ideal leak rate for those using a Respironics machine is the acceptable leak rate for the mask and pressure they're using. Won't be (and shouldn't be) zero for a Respironics machine user.

So you are saying the "mask setting" is the tables for that mask preprogrammed into the machine?

Yup. You set the mask setting, and the machine figures the intentional leak for the mask at the applicable pressure.

jdm2857 wrote:Yup. You set the mask setting, and the machine figures the intentional leak for the mask at the applicable pressure.

Since the available configuration settings are:

Full Face
Pillows
Nasal
Nasal Ultra (specifically for the Ultra Mirage, as I understand it)

When one uses the "Full Face" option, the S9 will use an internal table that might, or might not, be exactly the same as the Vent Flow Rate/Intentional Leak for the mask being used.

For example, the ResMed Ultra Mirage and the Mirage Quattro both show these Vent Flow Rates at the stated Pressures:

4 cm H2O - 22.0L/Min plus/minus 6.0L/Min
8 cm H2O - 32.0L/Min plus/minus 6.0L/Min
12 cm H2O - 41.0L/Min plus/minus 6.0L/Min
16 cm H2O - 48.0L/Min plus/minus 6.0L/Min
20 cm H2O - 54.0L/Min plus/minus 6.0L/Min

The other full face mask I have a table for is the Respironics ComfortGEL Full, which shows these Intentional Leak rates (approximately) at those same pressures:

4 cm H2O - 18.0L/Min
8 cm H2O - 25.0L/Min
12 cm H2O - 30.0L/Min
16 cm H2O - 35.0L/Min
20 cm H2O - 40.0L/Min

I would imagine the S9 uses an algorithm based on the measurements for the ResMed masks, hence, if someone was using the Respironics mask, they might see some reported leakage from ResScan that may be inaccurate when it falls outside the stated variability (6.0L/Min) - which looks to occur at pressures of 12 cm H2O and above.

Am I off-base with this analysis?

DHC, you are correct in your thinking. I use the S8 Autoset II and the RespCare Hybrid which vents more than the Resmed FFMs so I expect a bit of leak to be reported. If it's more than a little, I know I need to fix the leak.