AHI # and leakage rate #. Correlation?

Is there a correlation between AHI and leakage rate? Seems to me there would be. AHI of 2.96 and my 95% number for leakage was 68.4.

AIso, I would appreciate some clarification on the 95% number. It's my understanding that the number, in this case, 68.4, means that 95% of the time the machine was on the leakage rate was 68.4 or lower. Is this correct?

Thank you.

-Chuck-

I believe you're right about the 95%. And there is a correlation between AHI and leakage in that the larger the leak, the less treatment you're getting, which would translate to allowing fewer apneas to be caught by the machine.

I now recall reading that with a higher leakage reading, the AHI number is probably erroneous. Thanks. -Chuck-

Respironics say that they can do a good job compensating for leaks up to Large Leak territory. While they don't tell us exactly where Large leak is....from past experience it is around 90 L/min when reporting total leak.
So you are pushing it with your 95% number and warrants some work but I don't think that it is bad enough to impact the reporting of events. You are new to all this and with time and getting your mask adjusted better so less leaks, I think you are fine at this stage of things.

FWIW...I have seen large leak reported at 120 L/min on someone's report and it obviously did impact the machine because it was supposed to auto adjust the pressures and it didn't. So with a huge leak the machine throws up its tiny little hands and shouts "I quit"..

Stay well below 90 L/min and your machine can handle things. Also remember that the total leak reported includes the vent rate and if you are using higher pressures that vent rate will be higher. I don't remember your pressure settings so bear that in mind along with which mask you use...full face masks have a higher vent rate also when compared to nasal pillow masks.

And yes, 95% (Respironics actually use a 90% number on their Encore Reports) means that for 95/90 % of the time you were at OR below that number. A look at the leak line graph itself will give you a better idea as to how much time was spent with the higher leak but for the bulk of your night your leak is acceptable and I doubt it impacted your AHI at all because it is/was below 90 L/min.

Side note...ResMed users...your machines subtract the vent rate prior to reporting leak so what you see is all excess leak and thus this is why you have a 24 L/min red line for large leak territory.

So Respironics users...don't try to compare your leak numbers to ResMed users leak numbers unless you subtract out your mask vent rate at your average pressure.

My mask vent rate at my average pressure is 35 L/min and when using Respironics machines I sometimes saw minimal to zero leaks and sometimes saw leaks up around 50 L/min...no problem. On a rare occasion I have hit 80 L/min with no large leak flag but I have had large leak flag at 90 L/min. Even if I do hit 90 L/min it isn't the end of the world. It all depends on how long one spends at 90 L/min or above. 5 minutes is nothing to worry about....and hour...then maybe we worry and work on the leak a little better. So look at the whole picture and not a single number and you will have a better idea how things are going.

That said...any leak, even a small leak, that causes sleep disruption needs to be worked on for sure. Anything that disrupts sleep is unwanted. But if one sleeps through a few larger leaks and rarely hits large leak territory then I just shrug my shoulders and move on and trust the machine to do its job within it capabilities.

If the green face shows up on the S9 than probably leak is not a major concern otherwise his friend the red face shows up instead.

Mr Red Frown face doesn't show up on the screen until the leak exceeds 24 L/min for 30 % or more of the night.
So out of an 8 hour night if someone spent 1/4 the night in large leak Mr Red Frown Face wouldn't show up but 25% of 8 hours is 2 hours and I for one wouldn't be happy with 2 hours of large leak. This is why we look at the graphs themselves and not rely totally on Mr Green or Mr Red to tells us about our leaks.

I had this ugly night not long ago. It did not meet Mr Red Frowny face criteria. This was a very rare occurrence for me but I sure wouldn't be happy with this night after night no matter how many times Mr Green was smiling at me.

viewtopic.php?f=1&t=76445&p=698087&hili ... ne#p698087