Leak Rate Question

[PaulaO2]

So I'm using the Simplus FFM. It's leak rate for my treatment pressures is way higher than ResMed's rule of thumb of 24 L/m.



Going by this, I can ignore any Large Leak SleepyHead reports that is 50 L/m and under, right?

And I just spent the past, I dunno, half hour or more trying to find the latest intentional leak sheet at the PR site so I could find out the leak rate for the Nuance. OMG every link opened a new tab. And none of them led me anywhere even close to what I wanted. Not even the Nuance page had any technical information. Not even Google could find it. It found an older link from Zonk but that pdf doesn't include the Nuance.

I found the F&P one, here: (pdf file) http://www.fphcare.co.nz/files/documents...low-sheet/

[DeepBreathing]

Paula, as I understand it, the 24 L/min is in excess of the deliberate leak built into the mask. So if there's an intentional leak of say 40 @13 cm H2O, then anything above the 40 is counted towards the 24 limit. Once the total leak got to 64, then your unintentional leak is too high. Having said that, I have to assume that the ResMed machines have a means of computing the deliberate leak at each pressure for each of the basic mask types.

[PaytonA]

Having said that, I have to assume that the ResMed machines have a means of computing the deliberate leak at each pressure for each of the basic mask types.

Yes they do and it works for each individual mask. I have copied an explanation of the method into several threads previously but it seems to get everyone stirred up, so I will refrain from doing it again. If you are interested I will PM it to you.

Best Regards,

PaytonA

[DeepBreathing]

Having said that, I have to assume that the ResMed machines have a means of computing the deliberate leak at each pressure for each of the basic mask types.

Yes they do and it works for each individual mask. I have copied an explanation of the method into several threads previously but it seems to get everyone stirred up, so I will refrain from doing it again. If you are interested I will PM it to you.

Best Regards,

PaytonA

Thank you - I'd appreciate it.

[PaytonA]

So I'm using the Simplus FFM. It's leak rate for my treatment pressures is way higher than ResMed's rule of thumb of 24 L/m.



Going by this, I can ignore any Large Leak SleepyHead reports that is 50 L/m and under, right?

And I just spent the past, I dunno, half hour or more trying to find the latest intentional leak sheet at the PR site so I could find out the leak rate for the Nuance. OMG every link opened a new tab. And none of them led me anywhere even close to what I wanted. Not even the Nuance page had any technical information. Not even Google could find it. It found an older link from Zonk but that pdf doesn't include the Nuance.

I found the F&P one, here: (pdf file) http://www.fphcare.co.nz/files/documents...low-sheet/

Paula, if you are using an S9 Autoset as your profile says, the machine only reports unintentional leak. The upshot is that you should maintain the leak rate below 24 l/min. If Sleepyhead is reporting two different leak rates, it must think that you are using a PR machine for some reason

[PaulaO2]

No, just one leak rate. But it has that red line at 24. So I have always assumed that anything above 24 was evil.

Now I am confused. Easy to do, sure.

How does the Autoset know that the Simplus has that intentional leak rate? Or is that about the norm for all FFMs? Just checked. It's about right, give or take a few L/m. So I tell the machine I have a Full Face Mask. It changes its formula for accommodating leaks. SleepyHead tells me I had leaks up to 45. So that means It was 21 higher than it should have been. Right?

[PaytonA]

No, just one leak rate. But it has that red line at 24. So I have always assumed that anything above 24 was evil.

Now I am confused. Easy to do, sure.

How does the Autoset know that the Simplus has that intentional leak rate? Or is that about the norm for all FFMs? Just checked. It's about right, give or take a few L/m. So I tell the machine I have a Full Face Mask. It changes its formula for accommodating leaks. SleepyHead tells me I had leaks up to 45. So that means It was 21 higher than it should have been. Right?

The designation of the mask type simply tells the S9 what pressure drop to expect from the mask, which together with the hose type tells the S9 how much pressure is required at the machine to yield the correct therapeutic pressure at the mask.

The unintentional leak rate is determined dynamically by the machine. It is a somewhat complex process that I have posted before but the upshot is a reasonably accurate evaluation of unintentional leaks.

Yes, when Sleepyhead tells you that your leaks are 45 l/min that means that they are 21 higher than what the S9 would like to see in order to give accurate scoring and therapeutic pressure.

I think that you and I have somewhat similar problems getting FFMs to seal well. The bridge of my nose is recessed from my forehead toward my face quite a bit. The way the Simplus is designed, I have to get the forehead stabilizer flat against my forehead and then tighten the lower straps quite a bit in order to seal at the nose. Even then I still get small leaks at times.

Best Regards,

PaytonA

[PaulaO2]

Well dang. So even though it has a higher intentional leak rate, I still gotta stick to the limit of 24? That stinks. Here I thought I could get away with more.

Yes, it is at the top of the nose where I leak. Some at the sides of my mouth. That's where the farts happen. But the steady leaks are at the top.

[justMongo]

My mask vent rate is below. Not that different that your mask.