Meaning of System Leak Numbers

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RachelM
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Meaning of System Leak Numbers

Post by RachelM » Sat Oct 21, 2006 4:45 pm

Have a RemStar Auto w/cflex. What exactly do the System Leak Numbers Mean? FYI: My current 7-day average is 30.5, 30-day average 31.0. Have no idea what is normal, what means mask leak.


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Wulfman
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Post by Wulfman » Sat Oct 21, 2006 5:09 pm

It all depends on what mask you're using and what pressure your machine is set to. When you received your mask, there SHOULD have been a little pamphlet that gives the "Vent Flow Rate" at various pressures.

Depending on those variables (mask, vent flow rate and pressure), whatever percentage is above that typical vent flow rate number would be considered a "leak rate".

If you don't have the chart that came with your mask, and if you supply the information to us, someone here might be able to help tell you if it is above normal.

Best wishes,

Den
(4) REMstar Autos w/C-Flex & (6) REMstar Pro 2 CPAPs w/C-Flex - Pressure Setting = 12 cm.
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RachelM
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Post by RachelM » Sat Oct 21, 2006 5:14 pm

Thanks for reply. Mask is ComfortLite2--currently using nasal pillows.


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Post by RachelM » Sat Oct 21, 2006 5:16 pm

Oops-forgot to post pressure along with mask type. I have an auto, 90% average stays between 9.3-10.1.


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Wulfman
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Post by Wulfman » Sat Oct 21, 2006 5:17 pm

Here's a website with charts for which the users of various masks submitted information.

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

It looks like about a 27 or 28 is about typical for that pressure, so I would think you're pretty close to those numbers.

Den
(4) REMstar Autos w/C-Flex & (6) REMstar Pro 2 CPAPs w/C-Flex - Pressure Setting = 12 cm.
"Passover" Humidification - ResMed Ultra Mirage FF - Encore Pro w/Card Reader & MyEncore software - Chiroflow pillow
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dsm
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Post by dsm » Sat Oct 21, 2006 5:23 pm

This chart lists a range of leak rates for various masks.

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

If the leak data in your print out, matches the data for the mask at the av CMS you are using, then it is likely the leak data is normal.

Some brands of machines allow you to select a maskmodel & the data from those machines deducts the known leak rate from the info displayed so they sho 0 leaks when there are zero leaks. Nice feature

DSM
xPAP and Quattro std mask (plus a pad-a-cheek anti-leak strap)

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Post by chdurie2 » Sat Oct 21, 2006 8:42 pm

I also have a question along these lines for dsm or anyone.For the several months that I have had my (do I dare say it here?) Resmed Vantage, my leak rate has been running at .02-.06 with a UMFF at 7 to 13 pressure. Then last week, it unexplainably went to .26, but my average AHI was also declining from about 3 to about 1.9. I thought there was some major leak, so I examined the mask carefully and there is something wrong with the elbow joint so I tried to slip that back into place as best I could. It is not perfect, but I cannot get it any better. The leak then was running about .31, so I used other masks for a few days but their leak rates have been no better. I've been worried about these leaks, but dsm, what you're suggesting is that perhaps the machine is no longer, for some reason, adjusting for these built-in leak rates?

Thanks.

Caroline


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NyNurse33
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Post by NyNurse33 » Sun Oct 22, 2006 8:01 am

I have a stupid question.....What if your leak rate is less than the manufacturer's numbers? That is not going to involve a problem with Co2, is it?
~Melissa~

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Post by NyNurse33 » Sun Oct 22, 2006 8:03 am

BTW, I have to laugh, that chart doesn't even have my pressure listed...90% pressure--average around 5.8. But I checked the pamphlet. Also, its funny that on the resmed escape, they had me at straight cpap of 10 and I haven't even come close in the 2 1/2 weeks on auto.

~Melissa~

The best bridge between despair and hope is a good night's sleep. ~E. Joseph Cossman

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Post by arthuranxious » Sat Oct 28, 2006 10:40 pm

I am using Swift nasal pillows with a resmed S8 autoset and getting leak rates of about .46 to .54, I thought that was pretty good, but you are doing much better. The chart taht was referenced earlier seems to be based on other measurements altogether.


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Post by rested gal » Sat Oct 28, 2006 11:33 pm

http://thorax.bmjjournals.com/cgi/reprint/61/3/226.pdf

On page 3, in the section "CPAP data" of this study:

"a 95th centile leak of ,0.4 l/s was considered acceptable)."
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Post by greyhound » Sun Oct 29, 2006 5:40 am

I wonder if, in Remstar/Encore Pro terms, anything over 0.40 l/s would be classified as a "major leak", the point at which the CPAP/APAP can no longer compensate for the leak.


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Post by Guest » Sun Oct 29, 2006 6:23 am

So far this is all Greek to me and I'm not really grasping any of it. I do know altho I felt no leaks my sleep lab manager when assisting me w/the fitting of two masks I was having trouble with said the one mask was of no value to me as we could not get it adjusted comfortably and still maintain an acceptable leak rate (when checking fit and leakage w/machine at my pressure). The nasal pillows we could fit somewhat comfortably and still maintain an acceptable leak rate - except that the fit wasn't that comfortable after an hour or so.

So, now a third mask. This time it is the ComfortLite 2 which has remained comfortable for 5 nights now.

Scripted Pressure is Inhalation 6, Exhalation 3. Resmed S8 Elite w/Humidaire 3i. Mask set for Ultra first 4 nights, for Swift last night.

Leak rates:

Pressure: 5.6 - Leak: 0.36 - AHI: 7.4 - AI 0.2 - HI: 7.2 - Ultra
Pressure: 5.6 - Leak: 0.42 - AHI: 4.3 - AI: 0.08 - HI: 3.5 - Ultra
Pressure: 5.6 - Leak: 0.52 - AHI: 5.6 - AI: 0.4 - HI: 5.2 - Ultra
Pressure: 5.6 - Leak: 0.50 - AHI: 13.6 - AI: 0.4 - HI: 13.2 - Ultra
Pressure: 5.8 - Leak: 0.60 - AHI: 13.8 - AI: 0.2 - HI: 13.6 - Swift

Tonight I'll select yet another Mask setting & see what results I get. It sure would be interesting to know how low my 02 sats go during the hypopneas.


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Post by chdurie2 » Sun Oct 29, 2006 12:09 pm

rested gal:

does that mean i can wear my mask looser? I wear it (UMFF or F&P 431)very tight in order to get leak rates of .04-.08, so tight that i have face marks in the morning (not strap marks). certainly a looser mask would be more comfy. i thought that leak rates of .40 would be unacceptable and would occur with looser fitting mask? So should I stop harnessing myself in and give a little?

thanks.

caroline

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