Mask Leak Rate Experiment

[Zeke351]

I have been using the Mirage Quattro FF Mask for about 2 months now. Ever since I started using it the leak rate reported on my machine (F&P Sleepstyle 244) was way too high. It always stayed right around 60 l/pm, give or take 2 points either way. To me the seal feels great, no sounds of leaks, no feeling of air blowing on me, etc.

I mentioned this to my DME provider early on and she said I needed to get the strap adjustment right and it would get better. So, after 2 months of 60's, I decided to run an experiment last night. I sealed the mask under the silicon seal with a plastic sheet. I verified that there were no leaks except out the exhaust vent. I even went so fas as to use soapy water around the edges to look for bubbles of leaking air. I then let it run for 2.5 hours. When I checked the reported leak rate on the machine, guess what it said? Thats right a straight 60 l/pm and no AHI!

I have a new call in to my DME!

What do all of you think is the problem? The vent rate on this mask at 10psi should be 35. Is it the mask venting more then it should or is it the machine reporting the wrong number? Could it be something else?

Your thoughts are very welcome.

Zeke351

[sleepmba]

There could be a leak coming from somewhere else other than where it seals to your face.
-there could be a hole in your hose
-the mask may not be assembled properly...if you took it apart to clean it, sometimes it's hard to get the parts back together tightly
-sometimes the exhaust port vents too much or is out of adjustment

Check the rest of your "plumbing" when the machine is running. If you have another mask, try it out and see if it shows an abnormally high leak too...

Just some thoughts...

[Zeke351]

There could be a leak coming from somewhere else other than where it seals to your face.
-there could be a hole in your hose
-the mask may not be assembled properly...if you took it apart to clean it, sometimes it's hard to get the parts back together tightly
-sometimes the exhaust port vents too much or is out of adjustment

Check the rest of your "plumbing" when the machine is running. If you have another mask, try it out and see if it shows an abnormally high leak too...

Just some thoughts...

sleepmba

Thanks for the response, I really appreciate it.

Well I checked the hose and not even a pin hole to be found. I submerged the hose with the pressure on, capped the end, and not a single bubble. Reversed the hose and checked the other end and the same thing. Then I sealed the mask and submerged it up to the exhaust vent with the same result.

Do CPAP machines ever need to be calibrated?

At this point I am I am at a loss. I am figuring it is either venting at a rate higher then it is suppose to either by design or defect, or my machine is not monitoring properly. I will ask my DME rep for more information and go from there.

Any other ideas please let me know.


Zeke351

[wlenz]

What is your pressure setting? The leak rate for this mask is 22 L/min +/- 6 L/min up at a pressure setting of 4 cm H2O. The leak rate is 54 L/min +/- 6 at a pressure setting of 20 cm H2O.

Bill

[Zeke351]

Bill,

My pressure is set at 10 and I do not use the ramp feature at all. So the leak rate should be around the 36 +/-6 mark. So at the upper end I should be looking at 42 or so NOT 60.

The RT at the DME provider is NO HELP AT ALL! After I explained how thoroughly I tested for leaks she told me to "just ignore it"

When I told her that I was concerned about the AHI and other readings being off if the unit can't figure out the flow rate properly, she basically said I was over thinking it and not to worry. So I asked her how I could trust the data if, like computer programming, if you put crap in you get crap out. She said that because I wasn't using a F&P Mask the unit couldn't adjust for a mask that was from another manufacturer. I then asked her "Isn't a leak rate a leak rate regardless of who makes it and where it leaks?" She got real snippy at that point and said "She was 100% sure that there was nothing wrong with the CPAP machine." This without ever having seen the machine! So I told her, I am 1 month from insurance covering a new mask and I will get a F&P mask at that point and see if there are changes to the leak rate and we will take this up again then. All she could say was that she didn't like F&P's FF masks. I told her that was ok because I love the fit of the Quattro and I could always switch back if I didn't like it.

I think I piss her off because I won't back off just because she thinks she is the expert! Welcome to a thinking CPAP users world!!

Zeke351

[GumbyCT]

You are prob talking over her head. Things she doesn't understand. Each machine or mask can vary a bit. Do you have software to see if the leak graph is linear? That would be useful.

FP masks do tend to leak more. Do you have to enter the mask model into the FP machine?

[Zeke351]

You are prob talking over her head? Things she doesn't understand.

.

LOL Thats what I was thinking. She certainly acts like she knows it all. I love having a battle of wits with an unarmed person!!!

Each machine or mask can vary a bit. Do you have software to see if the leak graph is linear? That would be useful.

FP masks do tend to leak more. Do you have to enter the mask model into the FP machine?

I do have the software and the leak graph is linear. Except when I have to open it to scratch my nose.

The F&P Macine only has listings for their specific models.

Thanks for the input.

Zeke351

[GumbyCT]

You are prob talking over her head? Things she doesn't understand.

.

LOL Thats what I was thinking. She certainly acts like she knows it all. I love having a battle of wits with an unarmed person!!!

Each machine or mask can vary a bit. Do you have software to see if the leak graph is linear? That would be useful.

FP masks do tend to leak more. Do you have to enter the mask model into the FP machine?

I do have the software and the leak graph is linear. Except when I have to open it to scratch my nose.

The F&P Macine only has listings for their specific models.

Thanks for the input.

Zeke351

Is there any chance the wrong mask model has been entered?

Can you post a graph for us to see?

[Zeke351]

GumbyCT,

Thanks for the response. The Sleepstyle doesn't have entries for masks other then from the same manufacturer. I do have the F&P Full Face entered into it though. This machine does not adjust in its reporting for the masks, it reports the exhaust flow, mask leak and mouth leak all in one number so the mask setting really should not effect it.

I am away from home for the next couple of days but I can post a graph in a couple of days.

Thanks again,

Zeke351

[GumbyCT]

GumbyCT,

Thanks for the response. The Sleepstyle doesn't have entries for masks other then from the same manufacturer. I do have the F&P Full Face entered into it though. This machine does not adjust in its reporting for the masks, it reports the exhaust flow, mask leak and mouth leak all in one number so the mask setting really should not effect it.

I am away from home for the next couple of days but I can post a graph in a couple of days.

Thanks again,

Zeke351

Said another way try changing what is entered currently (for your mask) to see if/how that impacts your readings. If there is an entry for a mask then it must adjust something or it wouldn't be there. Just a thought.

[Bearcat42]

That is odd how the machine only recognizes one type of mask. Why would a manufacturer do that when there are so many different masks? I too suspect that the problem lies in the mask leak rate setting but if that can't be changed for a different brand of mask then what. The RT seems like a real nitwit and I applaud your efforts to troubleshoot the problem and find a solution.

[Zeke351]

The F&P Sleepstyle 244 has other mask entries for the other masks made by F&P but no other manufacturers. I have tried other mask settings and none of them affect the leak reporting. I think the entry is only to show the mask on the reports that print and does not effect any settings.

Zeke351

[GumbyCT]

The F&P Sleepstyle 244 has other mask entries for the other masks made by F&P but no other manufacturers. I have tried other mask settings and none of them affect the leak reporting. I think the entry is only to show the mask on the reports that print and does not effect any settings.

Zeke351

While that is not a bad thing - printing the mask model on the chart - not having a machine like everyone trying to help you makes it challenging.

The only other thing I can suggest is to remove the mask - block or tape the end of the hose and run the machine long enuff to get an idea where the leak starts to plot on your software without the mask. Maybe you could post that. That should give you a baseline, the rest will be due to the mask vent, mask leaks, or mouth leaks.

[Zeke351]

Here are the graphs from my last 7 days and the detail from just last night. As you can see the pressure is constant, except when my nose itches LOL
I will test some more as I can and report back. But I really think somethng is out of whack here! My therapy feels good though.

Zeke351

[GumbyCT]

Certainly something it out of whack. But is it the mask or the machine?

If blocking the hose shows anything significant then maybe you'll also want to try taping over the exhaust to see if blocking or restricting it will show anything. People get excited if the exhaust is blocked so you don't want to do this for more than 5-10 minutes. Just long enuf to plot on the software and see where it shows up.

This could give you some leverage with the DME. But then it just might be better to find another and get a different brand of machine.