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HELP?! What *IS* the correct magic number for a leak to be too high?
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Peter_C Offline

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Posts: 1,308
Joined: Sep 2013

Machine: System One DS960HS
Mask Type: Full face mask
Mask Make & Model: Mirage Quattro "MED"
Humidifier: Attached
CPAP Pressure: Auto mode-script is:15/3/3
CPAP Software: EncoreBasic Other Software

Other Comments: Severe obstructive sleep apnea 1999/Just got an ASV machine

Sex: Male
Location: Akron, Ohio USA

Post: #1
HELP?! What *IS* the correct magic number for a leak to be too high?
Color me confused?

Leaks suck, I know this. The less leaks you have, the better it is, I know this as well...

But, what is considered to be the magic number that we need to keep our leaks *BELOW*??

And, is it "L/s" or "L/m" (in other words, liters per second, or liters per minute)??

My machine reports L/s (liters per second), but that's OK, I can do the math to figure out L/m (liters per minute) too Smile

I've been reading and reading, and thought I had read it was 24L/m. But then, I just read a post which stated, 24L/s - a big difference!

For a Resmed machine, how large must a leak be (or stay at) for the machine to have a possible issue dealing with the leak, and/or, cause a risk of possible incorrect data? In other words, can someone simply give me a reasonably correct number to have as a *rule* or goal to attempt to stay under please?

Also - a two-part question? Where can I find what the nominal leak rate is for a given mask, and, is there a way (or a need) for us to tell our machine about the mask so that it can handle the normal/nominal leak rate created (on purpose) by said mask?

Thanks~!!

*I* am not a DOCTOR or any type of Health Care Professional. My thoughts/suggestions/ideas are strictly only my opinions.

"Only two defining forces have ever offered to die for you. Jesus Christ and the American Soldier. One died for your Soul, the other for your Freedom."
10-23-2013 09:25 PM
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zonk Offline

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Posts: 7,908
Joined: Feb 2012

Machine: A10 AutoSet
Mask Type: Nasal mask
Mask Make & Model: Activa LT
Humidifier: Integrated /ClimateLineAir
CPAP Pressure: 9/13
CPAP Software: ResScan

Other Comments: CPAP since Nov 2010

Sex: Male
Location: Australia

Post: #2
RE: HELP?! What *IS* the correct magic number for a leak to be too high?
S8 report leaks L/s ........... S9 reports leaks L/m
0.4 L/s = 24 L/m

Both machines subtract intentional leak from total leak and reports unintentional leak

For this reason, you need to tell the machine type of mask using so it can work out unintentional leak
ResScan leak graph shows a red line at 24 L/m (0.4 L/s)
ResMed consider leak below the red line an acceptable leak
(This post was last modified: 10-23-2013 09:40 PM by zonk.)
10-23-2013 09:35 PM
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Peter_C Offline

Advisory Members

Posts: 1,308
Joined: Sep 2013

Machine: System One DS960HS
Mask Type: Full face mask
Mask Make & Model: Mirage Quattro "MED"
Humidifier: Attached
CPAP Pressure: Auto mode-script is:15/3/3
CPAP Software: EncoreBasic Other Software

Other Comments: Severe obstructive sleep apnea 1999/Just got an ASV machine

Sex: Male
Location: Akron, Ohio USA

Post: #3
RE: HELP?! What *IS* the correct magic number for a leak to be too high?
Thank you, and just to make triple sure I understand; Whatever leak rate is listed on the LDC screen of my machine, is *after* the machine has already subtracted what it thinks is the intentional (leak rate caused by exhaust port of mask), and is only showing me what it thinks is the unintentional leak rate? Correct?

Out of the available options for mask, I've chosen 'standard' mask.

*I* am not a DOCTOR or any type of Health Care Professional. My thoughts/suggestions/ideas are strictly only my opinions.

"Only two defining forces have ever offered to die for you. Jesus Christ and the American Soldier. One died for your Soul, the other for your Freedom."
10-23-2013 10:19 PM
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robysue Online
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Advisory Members

Posts: 1,240
Joined: Oct 2013

Machine: PR Dreamstation BiPAP Auto
Mask Type: Nasal pillows
Mask Make & Model: Swift FX
Humidifier: PR Dreamstation humidfier
CPAP Pressure: min EPAP = 4; max IPAP = 9;
CPAP Software: SleepyHead EncoreBasic EncorePro

Other Comments: Papping since September 2010

Sex: Female
Location: Buffalo, NY

Post: #4
RE: HELP?! What *IS* the correct magic number for a leak to be too high?
(10-23-2013 09:25 PM)Peter_C Wrote:  But, what is considered to be the magic number that we need to keep our leaks *BELOW*??

And, is it "L/s" or "L/m" (in other words, liters per second, or liters per minute)??

My machine reports L/s (liters per second), but that's OK, I can do the math to figure out L/m (liters per minute) too Smile
Resmed machines that are of the S8 vintage or earlier report leaks in L/sec and the Red Line for Large Leaks is drawn at 0.4 L/sec.

Resmed S9 machines (the current generation) report leaks in L/min and the Red Line for Large Leaks is drawn at 24 L/min.

For those who don't want to do the math: 0.4 L/sec = 24 L/min

To further clarify the issue:

Resmed machines report ONLY the excess leak. Hence there is NO need for a Resmed machine user to need to know the intentional leak rate for his/her mask. (That's why there is a mask setting on the Resmed machines---it's there to tell the machine how much to subtract off the raw leak rate data.) The intentional leak rate has already been subtracted from the leak rate data before it is recorded onto the card and shown to the the user through the machine's LCD or through ResScan or SleepyHead.

So for a user of a Resmed machine, the ideal leak rate is 0.0 L/sec (if you're using an S8 or earlier machine) or 0.0 L/min (if you're using an S9 machine)

But to muddy the waters for just a bit: It's important for RESMED users to realize that when they're reading posts about leaks from Respiroinics users and from F&P users, these machines report total leaks, which include the intentional leak rate for the mask. A PR System One user will NEVER see a leak rate of 0.0 L/min because the intentional leak rate of the mask is being reported in the leak data. The ideal leak rate for a PR System One user is a leak rate right around the expected intentional leak rate for your mask at the pressure you are using.
10-23-2013 10:37 PM
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