AirSense10AutoSet & AmaraView mismatch?

[bazder]

My AirSense 10 AutoSet gives me a red "frowny face" for mask leak (32L/min, pressure=12.3) but the AHI is 2.3 TotalAI is 1.4 and CentralAI is 0.3

myAir.resmed.com gave me an overall score of 82 but I don't really understand any of these numbers.

Do I have a mask leakage problem with the Amara View or is it just that AirSense doesn't understand that mask? Am I doing good with AHI = 2.3 ? What is the difference between AHI, TotalAI and CentralAI ?

[justMongo]

When leaks are not well controlled, then one cannot trust the data during periods of high leak.
That's one reason why many of us use software and look at graphs of events, flow, pressure and leak versus time.

And, yes, you have a leak problem at 32 LPM.

[bazder]

I stumbled across another post that mentioned leak rates jumping from 20's to 30's when changing mask to Amara View but can't recall the details. I think they were guessing the higher venting of mask got read as if it were a leak but actually wasn't? Is that possible or is 32L/min a leak regardless of which mask/manufacturer ???

[justMongo]

OK, let's examine that.
Below is a graph of vent rate versus pressure. The top line is the Amara View.
At a pressure of 12, it vents about 50LPM.


Then we have the vent rate for my Mirage Quattro FFM.
At 12, it vents about 41 LPM.


So, the Amara View vents about 9 LPM @P=12 more than the Mirage Quattro.
The machine can tolerate up to 24 LPM of leak.
If you have no leaks (other than vent rate) the machine might assign 9 to leak.
So, we're good. At worst, with your mask @P=12, your machine can tolerate 16 LPM of leak.

[bazder]

Phillips Respironics has a .pdf giving intentional leak rates for different masks but I'm not allowed to post links here yet. If I understood it correctly I think they estimate about 28L/min for the Amara View mask.

So, for instance, if my AirSense 10 AutoSet says my leak rate = 32L/min at pressure 12.3 what is the actual leak rate? Would it really be more like 32 - (~28) = ~4L/min and would that be OK even though the AirSense says "red frowny face" for mask leakage?

I'll send the link when I'm allowed ...

[justMongo]

Phillips Respironics has a .pdf giving intentional leak rates for different masks but I'm not allowed to post links here yet. If I understood it correctly I think they estimate about 28L/min for the Amara View mask.

So, for instance, if my AirSense 10 AutoSet says my leak rate = 32L/min at pressure 12.3 what is the actual leak rate? Would it really be more like 32 - (~28) = ~4L/min and would that be OK even though the AirSense says "red frowny face" for mask leakage?

I'll send the link when I'm allowed ...

First, vent rate is proportional to pressure. Your mask vents 28 LPM at 4 cm-H₂O. At 12 cm-H₂O, it vents about 50 LPM.

Then, ResMed machines report unintended leak rate.
i.e. -- they subtract calculated vent rate and report that.

So, if it reports 32 LPM at 12 cm-H₂O, that is the Total minus (let's use my ResMed FFM as the standard) the 41 LPM vent rate for my mask.

At 12 cm-H₂O, there is a delta of 9 LPM in the vent rates of the two masks. ergo, the ResMed machine may overestimate true leakage by 9 LPM at 12 cm-H₂O.

Using that delta of 9 LPM, let's correct the calculated leak rate for your mask at 12 cm-H₂O. 32 LPM (reported) - 9 LPM delta = 23 LPM calculated actual leak rate.

But, the machine sees 32 as the leakage; and you do not get a smiley face. Plus, with the extra 9 LPM, the blower unit may not be able to keep up the pressure.

That's why I strongly urge you to use software to see what the actual pressure is during times of reported Large Leak. And for you, I would suggest ResScan.

Kindest Regards,

Mongo

[bazder]

justMongo: awesome answer, thank you

I only have an iMac and a Linux(Ubuntu) laptop so I'm not sure I can use Res Scan. There may be a chance of compiling a linux version of SleepyHead from source code but I'd like to avoid compiler flags if possible!

Is there a Mac version of Res Scan? Does the WiFi SD card thing really work? I'd like to avoid swapping the SD card in & out , especially if Mac will rewrite it with it's silly folders/etc. Any advice for my particular computer situation RE: CPAP analysis software ?

[justMongo]

ResScan is Windows only; and there is no access to source code to compile and link for MAC.
So, you're stuck with Sleepyhead. SH is not a bad program. I just like the way it handles Leak rate for ResMed machines.
There's a software support sub forum for help with software.

Some people are having good results with the wifi SD card. I'm not sure about compatibility with MAC or Linux.
I'm considering trying it. One thing I've read is that power loss will require some work to get the machine to recognize the SD card again.
You'll need to get help from the SW forum on that. I know user AlanE is using a wireless SD card. There are quite a few SW developers on the board. I consider myself proficient user; but my programming skills are of the FORTRAN era.

I've not had any issues with swapping my SD card to/from my W7 computer and my S9 ResMed on a weekly basis.
I think your 10 series machine holds 30 days of high sample rate data; so you could download at 30 day intervals.
(Except when you want to see data more frequently to see what's going on.)

[zonk]

As far as ResMed machines concerned, total leak and mask vents leak rates are not relevant, the machine do the calculation and report "unintentional leak" (total leak - mask vents leak rates) ... easy peasy
You'll need to select type of mask you're using

Happy face means, leak was something like, less than 24 L/m for at least 70% of the time

The high leak rate is also the causes of dry mouth discussed here http://www.apneaboard.com/forums/Thread-...um-disease

[justMongo]

As far as ResMed machines concerned, total leak and mask vents leak rates are not relevant, the machine do the calculation and report "unintentional leak" (total leak - mask vents leak rates) ... easy peasy
You'll need to select type of mask you're using

Happy face means, leak was something like, less than 24 L/m for at least 70% of the time

The high leak rate is also the causes of dry mouth discussed here http://www.apneaboard.com/forums/Thread-...um-disease

Yes, but for the machine to know the vent rate, it has a table in firmware for vent rate versus pressure. And, it has one for each mask type. ResMed would naturally use the vent rates for their masks to program those vent rate tables. Hence, for the PR Amara View mask, it will underestimate the vent rate; and will assign the difference to leak. That delta, at P=12, is 9 LPM. (more vent rate for the Amara View that my ResMed Mirage Quattro.)