High leakage or machine malfunction?

[Bobby120446]

I have an older Resmed M Series autopap with humidifier. I use a full face mask. I feel very little air leakage around the edges of the mask. If I press the mask against my arm so there is NO leakage, I don't hear any air escaping from the tubing or within the machine -- it is very quiet. But weekly statistics always show air leakage, like 88 L/Min. Isn't that an extremely high leakage, and shouldn't it be obvious to me where the leakage is occurring? Or is there something else going on that I am missing? The weekly statistics always show apneas, anywhere from 1.6 to 6.5 per hour. But the statistics show NO increase in pressure -- average pressure is always 12, which is the same as my minimum pressure setting. I think that the auto-adjust feature gives up and doesn't even try once the leakage goes above about 70. Ideas, anyone?

[englandsf]

Do you have another mask you can test with to eliminate the mask as the source? Your AHI ratings will be almost meaningless if that is your true leakage rate too.

[LSAT]

If the machine ALWAYS shows a pressure of 12, perhaps it is set on CPAP and not Auto.

[Bobby120446]

If the machine ALWAYS shows a pressure of 12, perhaps it is set on CPAP and not Auto.

Nope. Once in a great while I will see leakage in the 60s, and then the pressure numbers go up to 12.5 or 13.0.
What leakage numbers do you typically see (if your machine shows them)?

[Wulfman...]

I have an older Resmed M Series autopap with humidifier. I use a full face mask. I feel very little air leakage around the edges of the mask. If I press the mask against my arm so there is NO leakage, I don't hear any air escaping from the tubing or within the machine -- it is very quiet. But weekly statistics always show air leakage, like 88 L/Min. Isn't that an extremely high leakage, and shouldn't it be obvious to me where the leakage is occurring? Or is there something else going on that I am missing? The weekly statistics always show apneas, anywhere from 1.6 to 6.5 per hour. But the statistics show NO increase in pressure -- average pressure is always 12, which is the same as my minimum pressure setting. I think that the auto-adjust feature gives up and doesn't even try once the leakage goes above about 70. Ideas, anyone?

First of all, there is no "ResMed M Series"........Respironics made the M Series machines.

Maybe your mask is the wrong size or is not adjusted properly. What mask are you using?

As was mentioned, an Auto machine can be set to a fixed pressure.......which is probably how your machine is configured.

But, if there is leakage, either with an Auto or fixed pressure, the "pressure" will NOT increase. The machine will try to increase the output/flow of air to maintain the pressure it was set to or last putting forth (in the case of Auto machines).

Please fill out your profile so we have some clue as to what you're using. And, if the equipment isn't available, put it in the "Additional comments" section like I have.


Den

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[Wulfman...]

If the machine ALWAYS shows a pressure of 12, perhaps it is set on CPAP and not Auto.

Nope. Once in a great while I will see leakage in the 60s, and then the pressure numbers go up to 12.5 or 13.0.
What leakage numbers do you typically see (if your machine shows them)?

It's going to vary according to the pressure in the mask. There should have been a user's manual with your mask that shows a pressure/leak curve. If you don't have it, you can always go to the manufacturer's website to download it.
But, at an approximate pressure of 12 cm., the normal leak rate should be around 38 - 40. I know because I've been using a fixed pressure of 12 for many years and track those numbers.


Den

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[Bobby120446]

First of all, there is no "ResMed M Series" … the "pressure" will NOT increase. The machine will try to increase the output/flow of air to maintain the pressure it was set to or last putting forth (in the case of Auto machines).

Sorry. REMStar M Series Auto with AFlex.

I meant, the machine would increase pressure in response to apneas/hypopneas, not to the leakage.
What are typical "acceptable" leakage numbers?

[Wulfman...]

You also didn't say whether you're using software (Encore Pro) or whether you're getting your numbers from the LCD.
And, if you're not resetting the machine numbers every night, you're probably getting skewed averages in the LCD.

From Encore Pro, there are several "Leak" numbers reported.

Average Max Leak

Average 90% Leak

Average Leak

Average Large Leak

If you're getting your leak numbers from the LCD, it may be a conglomeration/average of all of them.


Den

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[Wulfman...]

First of all, there is no "ResMed M Series" … the "pressure" will NOT increase. The machine will try to increase the output/flow of air to maintain the pressure it was set to or last putting forth (in the case of Auto machines).

Sorry. REMStar M Series Auto with AFlex.

I meant, the machine would increase pressure in response to apneas/hypopneas, not to the leakage.
What are typical "acceptable" leakage numbers?

The Auto machines will ONLY increase pressure in response to Snores and Flow Limitations.......NOT apneas and probably not hypopneas......in progress.


Den

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[cnaumann]

There should always be some leakage. It is an important part of the mask design; it keeps you from re-breathing your own air and suffocating. The leakage should be through vent holes in the mask, not around the seal.

Your mask should have come with a graph that shows the typical leak rate vs. pressure.

For something like an F10 Airfit, you should be seeing something like 50l/min leakage with a pressure of 16cmH2O.

http://www.resmed.com/us/dam/documents/ ... er_eng.pdf

Beyond this is gets complicated. ResMes and PR have different terminology and report leak rates differently. PR reports a 'total leak rate' which is the total amount of air going to the mask (I _think_. I am not actually sure if Total leak rate includes Minute Vent Rate or not. It usually does not matter.) There is a different leak rate reported that is the leak rate above what is expected from the mask. This leak rate would indicate a bad mask seal or possibly a calibration error.

88l / min at 16cmH20 sounds high to me even for a total leak rate, but I really don't know.

Is this a new issue?

[Bobby120446]

There should always be some leakage. It is an important part of the mask design, it keeps you from re-breathing your own air and suffocating. The leakage should be through vent holes in the mask, not around the seal.
...
Is this a new issue?

Yes, I taped over half the vent holes in the mask and could immediately notice the air was stuffy. Removed the tape and the air was fresh again.
It is not a new issue. Maybe I just need to trim my beard closer.

[Wulfman...]

There should always be some leakage. It is an important part of the mask design, it keeps you from re-breathing your own air and suffocating. The leakage should be through vent holes in the mask, not around the seal.
...
Is this a new issue?

Yes, I taped over half the vent holes in the mask and could immediately notice the air was stuffy. Removed the tape and the air was fresh again.
It is not a new issue. Maybe I just need to trim my beard closer.

It didn't occur to you to mention that little tidbit of information sooner???

GOOD GRIEF!


Den

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