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Leak Rate -- what does it mean? - Printable Version

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Leak Rate -- what does it mean? - Parisien - 11-16-2020

Bonjour from France,

To introduce a bit of my background, in July I spent two nights in a sleep centre to get more information about my REM Sleep Behaviour Disorder (RBD). During this stay, the sleep apnea was identified. So I went in with one problem, and came out with two! And a CPAP machine tucked under my arm.

I didn't have the sleep/tiredness symptoms which many people describe, but I do seem to sleep better with the machine.

So all's well, but I can't seem to do anything about the high leak rate, which is always around 30 each morning on my ResMed screen, with very little variation. My understanding is that 24 is the acceptable upper limit. I don't have any sense of a leak, and the little green man is always smiling each morning.

Looking at the statistics, the average leak rate is much lower, and the 30 number is described as the 95% leak rate, so I'm not sure which one I should be measuring against the 24 limit.

In addition, when I look at the detail of the leak rate, it seems to be all over the place, with high peaks and troughs. Is this normal?

Could it be associated with the RBD? My wife has wisely banished me to a spare room, so I don't know to what extent I'm moving during the night.

I would very much appreciate any insights. And I apologise if this question has been asked/answered before -- this board is so active, it's hard to read everything!


RE: Leak Rate -- what does it mean? - OpalRose - 11-16-2020

Hi Parisien,
Welcome to Apnea Board!

Just looking at your leak graph suggests that you are mouth breathing.  Are you aware of doing that?  One sign would be if you notice a very dry mouth when waking up.  

The spikes in a leak rate graph suggest mask movement, but when you see flat tops, then that is what we look for in mouth breathing.  You should take some steps to correct mouth breathing if you can.  Some here use a soft cervical collar, or practice the tongue technique.  Others resort to mouth taping.  If you can't control it, you may want to consider a full face mask in time.  Once the leak gets into large leak territory on a continuous basis, the Apap may not be able to detect apneas properly.

I also see that if you raise the minimum pressure to 8 and maximum to 14 with an EPR of 2, your sleep might be more comfortable. A minimum of 4 is too low for most adults. Use of EPR will help with the Flow Limitation and Hypopnea.


RE: Leak Rate -- what does it mean? - staceyburke - 11-16-2020

T completely agree with opal rose. You are maxing out ALL night, your top number needs to go up - 14 is fine, it will never go that high, it will go up as much as needed.

You have a large amount of flow limits. You use the EPR to help get them under control. 8 is a good starting place to allow the EPR to work.

So min=8
Max=14
EPR=3


RE: Leak Rate -- what does it mean? - Parisien - 11-17-2020

Many thanks for the suggestions. I'll make the changes to the settings today. So far, they've pretty much been as they left the hospital.

For the leakage, I'm still wondering whether there's any connection with involuntary movement due to the REM Sleep Behaviour Disorder. For what it's worth, I've noticed that there's very frequently a large leak rate period of about half an hour shortly after sleeping. I've no idea whether that has any significance.

Thanks again


RE: Leak Rate -- what does it mean? - Parisien - 11-19-2020

I applied the recommended settings, but one negative consequence is that the leak rate has shot up.

It had been consistently at or around 30, but the two nights with the new settings showed 48 and 44. All these numbers are from the front screen of the ResMed AirSense 10. (Incidentally, I do wonder how the little face picture is programmed -- it's always been cheerfully green, but finally turned red this morning).

Is this change in the leak rate a normal consequence of the increased pressure, or are further tweaks to the settings needed?


RE: Leak Rate -- what does it mean? - staceyburke - 11-19-2020

Your leaks are to high, you are not getting the therapy you need with these leaks.  If you put your mouse on the left side of the leak chart and right click (near the title leak rate) - you will see options.  In the options go to dotted line and choose the last option "leak rate upper threshold".  You will see a dotted line, any leak above that line your machine can not compensate for the leak and your therapy will suffer.  Any leak is not good and makes the machine work harder to control the apnea but over the dotted line it can't do much to help.  You have a lot of over the line that night.


RE: Leak Rate -- what does it mean? - Sleeprider - 11-19-2020

Well, you applied the higher pressure settings, but missed the exhale pressure relief (EPR) of 2. Be sure to scroll down to the comfort settings and turn EPR on full-time at a setting of 2.


RE: Leak Rate -- what does it mean? - Parisien - 11-19-2020

For some reason, the dotted line doesn't work for me, but no problem, I understand the point you're making.

Please bear with me if I try to understand about leakage. Four months ago, I had never heard of apnea, and it's a steep learning curve. For starters, the subject is a world leader for acronyms!

When I'm awake, with the machine on, I sometimes feel air pressure in my mouth, which is expelled by opening my mouth. Is this what's known as mouth breathing? Because it's not that I'm breathing through my mouth -- I'm only opening my mouth to empty out the air. And I'm not clear about how taping my mouth shut would help the situation.

Which leads me on to asking where is this air coming from -- is the machine delivering too much? And if so, what is the best way to deal with it?

Sorry if this is all elementary to the long-term veterans, but as I say, I'm at the bottom of the learning curve. And it goes without saying that I want to master the therapy.


RE: Leak Rate -- what does it mean? - Sleeprider - 11-19-2020

Most of us that us nasal masks and pillows learn technique to exclude air from the mouth and control the airway pressure. I can talk, or sip water with a straw and even open my mouth with out air rushing out. Most of this control comes from using the back of the tongue to block the airway at the roof of the mouth. "Mouth breathing" is probably not that common, but mouth leaking is, and it happens when the seal at the roof of the mouth is lost. This can happen when the jaw relaxes or the tongue drops down. The solution is to learn to control the airway, and one of the techniques is the "tongue suck technique".

Place your tongue to the roof of your mouth with tip of tongue behind front teeth. Slowly suck upwards and back.
This places the tongue in a natural position, with the back of tongue sealing the back of the throat so that if you open your mouth/jaw while sleeping, no air will escape.

Here is a link to a thread where members discuss this problem http://www.apneaboard.com/forums/Thread-CPAP-Air-Blowing-Out-of-Mouth?


RE: Leak Rate -- what does it mean? - Parisien - 11-19-2020

Thanks, I'll read through that thread.