Finally! A Leak Rate Recorded.

[Treesap]

I had a leak rate of .24L/s. What does it mean? My pressure was higher than usual too. Hubby actually woke me up last night to tell me I was leaking. It's taken some training, but he's catching on.

[DreamStalker]

Train that puppy! ... and before ya' know it, he'll be doing all sorts of tricks for you.

Anyway, I think it means you are leaking.

[Treesap]

I'm not familiar with what my leak rate is supposed to be because my machine rarely records any.

Can someone educate me on my leak rate?

[gasp]

Some masks come with documentation that speak to the mask's acceptable leak rate. Mine doesn't.

I don't worry about my leak rate unless my AHI is affected. If my AHI stays low, then I know I'm getting therapy.

As you see in this report, my leak rate is what I consider more on the high side and less on the low side (27.39) and my AHI is very low (0..



I'm not having any luck making this picture smaller to avoid making the post so wide. Sorry.

[bdp522]

Leak Rate for Optilife mask


pressure 4 leak approx 17
pressure 8 leak approx 25
pressure 12 leak approx 31
pressure 16 leak approx 46
pressure 20 leak approx 40

Keep in mind that resmed machines already have the leak rate figured in to the results. You set the machine to the correct mask, if it shows a zero leak rate it means that your leak does not exceed the acceptable leak rate.

Brenda

[Treesap]

My pressure last night was 11.6, but my leak was .24L/s. I'm not sure from what was listed puts me within an allowable leak rate because I don't understand the leak rates given for masks.

Could someone please explain?

I appreciate it.

[bdp522]

At a pressure of 11.6 the Exhaust leak rate is approx 30-31. If your machine is set correctly for your mask, your leak rate shown on the machine would be 0. Anything over 0 would be a leak that is over and above the acceptable leak rate( a real leak not just the exhaust). The optilife chart shows leak per minute, the resmed machine shows leak per second. so if you multiply the .24 leak you had by 60, it gives a leak of 14.4. Now, if the leak rate already figured in by your machine is 30, add the 14.4 and you had a leak of 44.4 at a pressure of 11.6, 14.4 pts higher than it should be. I have read that a leak on a resmed machine under .4 is ok. I like mine to be closer to the actual exhaust rate.

Brenda

[Flying_Norseman]

Gasp,

Some people would tell you that you can't trust your AHI numbers if your leak rate looks like that. I am not sure if they are right or not.

[rested gal]

I'd trust the AHI numbers on Gasp's Encore Pro chart with that reasonably under control (not perfect, but certainly ok to me) leak rate.

Treesap, I'd consider a leak rate of .24 l/s fine with a resmed machine, like you're using. It's when resmed leak rates hit over .40 l/s (liters per second) that the rate is too high.

Respironics machines measure leak rate in liters per minute.

Puritan Bennett machines measure it in liters per second.

resmed measures in liters per second with most of their machines.

[DreamStalker]

The designed or intentional leak rate is generally not a linear relationship ... one can see this by looking at a plot of leak rate versus pressure where the line is curved rather than straight.


The chart above is linked to jpg file posted by Robieh

One can also see that the trend shows that as pressure increases, so does the leak rate.

Finally, the ResMed S8 machines have a “mask setting” and depending on what that setting is, it will subtract the intentional (or normal/design) leak from the measured leak. As Brenda said, if you are truly not leaking, and you have the mask set to your mask, the LED/software will show a zero leak.

However, I am assuming that you are using the Optilife … ResMed machines do not have a setting for the Optilife (they only have settings for ResMed masks).

At a pressure of 11.6, your mask should have a leak rate of about 30 liters per minute.

You stated that your machine showed a leak of 0.24 liters per second which equals 14.4 liters per minute.

To determine your leak rate, you need to add 14.4 liters per minute to the “intentional” leak rate for the mask selected in you machine's “mask setting” when used at a pressure of 11.6 cm.

So, question is -- what is the mask setting on your machine set to?

[jasper]

I'm using the Optilife with the Respironics APAP machine, and I get a 30 day average of 30 to 38, at about 12 or 13 cm pressure. I've considered this to be pretty good, based upon the leak rate chart plus an allowable overage. What I don't understand is that the 30 day average on the LCD screen will show, say 32, and the 7 day average will be 1 or 2. Can't make any sense of that, but my AHI's have been pretty good, so I don't worry about it. Any ideas why this is different?

[Treesap]

So, question is -- what is the mask setting on your machine set to?

It's set to "standard". I tried the Swift setting a few weeks back, but that's when I started waking up feeling terrible, so I changed it back.

[Treesap]

If I understand correctly, a 14.4 leak rate is acceptable for my pressure range (10-11).

[jules]

from http://www.resmed.com/en-us/products/se ... _us_en.pdf

on the top of Page 31

STANDARD

Mirage Activa Nasal Mask
Mirage Vista Nasal Mask
Modular Nasal Mask


from http://www.internetage.com/cpapinfo/leak-rates-1.html

for the Activa

10.0 10.5 11.0 11.5 12.0 12.5 13.0

30.8 31.7 32.5 33.3 34.2 35 35.8


So based on this mini-research, it appears your intentional leak rate is between 33 and 34 (I hate to throw more significant digits in)

_________________

CPAPopedia Keywords Contained In This Post (Click For Definition): mirage, activa

[DreamStalker]

Interpolating from the chart posted by Bob a while back the Standard setting at 11 cm should be about 34 to 35 liters per minute.



That means that adding the 14.4 liters per minute makes your leak equal to about 48.4 to 49.4 (or about 49 LPM) for your reading of 0.24 LPS from the LED/software using the Optilife at 11 cm of pressure.

So your leak rate should be 30 LPM and you are getting 49 LPM … your leak rate is about 163% of what it should be. You should probably work on trying to get it down a bit IMO.