leak rate goes kaboom

Hi-

The below JPG is representative of my last few times on bipap! I took Rested Gal's advice and turned up my pressure a bit, and I'm doing a lot better than before... except for my leak rate. My data has been showing just this for the past few days: A nice, low, solid leak rate for the first two hours or so, then it gets... not nice and low, and I wake up. Anyone have any idea why this is happening? Am I just knocking my mask off? Do you need the rest of my info? My IPAP is currently 12.5, EPAP at 10.5.

-Grace

Yeah, it would help to also see the top part of that Daily Details graph...the part showing the pressure line(s.)

Even without that, off the top of my head -- since your equipment profile says you're using a FF mask (rules out mouth breathing with a non-FF mask) I'd say your mask is getting shifted to the point that the cushion can't hold a seal. Or if mask isn't actually getting moved, it could be that your jaw is dropping a lot. That can change the contour of your face causing leaks to pop out around the cushion. Some people have found they need to wear a chin strap WITH a FF mask, just to keep the jaw from dropping a lot.

Doesn't have to be an expensive commercial chin strap...just a homemade strap can accomplish that. And doesn't have to be tight -- you don't need to keep mouth closed with a FF mask. Just needs to prevent the jaw from dropping wayyyyy down.

http://www.scribd.com/doc/9519459/er <---- link to entire thing

It IS true, however, I've had difficulties with my chin dropping in the past, so maybe I'll try a chin strap tonight.

ciounoi, thanks for the link. I went there to look at the entire graph.

It's always hard to tell if it's "chicken or the egg", but from placing a straight edge against the pressure increases and the leak increases, it "looks" to me as if it's the pressure increases first, followed by corresponding leak increases. Which would mean (to non-medical me, anyway) that you might want to raise the EPAP minimum another cm or two, to see if that will prevent whatever the machine is sensing in your airflow that is making the machine need to use more EPAP...perhaps setting min EPAP on 9 or 10 cm.

But I'd go ahead and try a chin strap for a few nights to see if that settles things down.

What do you have the max press sup setting set on?

I am planning on raising both EPAP and IPAP... I just want to get slightly used to these new settings first.

My max supp is at 3.0. Apparently I can't change it?

ciounoi wrote:I am planning on raising both EPAP and IPAP... I just want to get slightly used to these new settings first.

My max supp is at 3.0. Apparently I can't change it?

It depends on what you have min EPAP and max IPAP set for in the first place, as to how much you can run the "max press sup" setting to. I always like to set the Max Press Sup for as much as it will allow, so that IPAP can work independently of EPAP as much as possible.

It looked like you have your machine set for this range: min EPAP 8, max IPAP 13.

13 minus 8 = 5

So, with your present min EPAP/max IPAP, " 5 " is the most the Max Press Sup setting will let itself be set to. You could set your "Max Press Sup" at 3, 4, or 5.

On you data, most of the time it was EPAP shoving IPAP up, to maintain the minimum 2 cm gap there always has to be between the two. EPAP can't be higher than IPAP, so if EPAP has to go up, but IPAP doesn't need to, EPAP is still going to push IPAP up, to keep that 2 cm difference between them.

If you were to set your machine for a range like this:
min EPAP 8, max IPAP 20, you could set the Max Press Sup for " 8 ".

Eight is the most the Max Press Sup will ever let you set it at, and that's only if there is at least 8 cm's of difference between your min EPAP and max IPAP settings in the first place.

Another example: If you set your machine to min EPAP 9, max IPAP 16, you could set the Max Press Sup for as much as " 7 ".

Any time I change my min EPAP/max IPAP pressure settings, I always check to be sure the "Max Press Sup" is set for as high as it will let me set it. I always check it, because.... if I start fiddling with the min EPAP/max IPAP settings, there might be some point at which I've run them close together before I finish "setting" them. During that fiddling, the Max Press Sup setting is automatically going to be "adjusted" down, if I've inadvertently brought min EPAP/max IPAP close together before I finally have them where I want them. The Max Press Sup setting won't automatically go back up, though. It will stay down where it got "automatically adjusted" to during the fiddling around with min EPAP/max IPAP.

So... in case that happened, I always take one last look at Max Press Sup again, before I exit from the menu. I want to be sure the Max Press Sup setting is run up to as much as it will allow.

____________________________________

Here are links to my understanding of the Maximum Pressure Support setting -- like two dogs on a leash.

That setting is called "Max Press Sup" in the M series BiPAP Auto.
It's called "PS" in the older non-M series BiPAP Auto.
Same thing.

viewtopic.php?t=22099
Jul 14, 2007 subject: What is 'Max Press Sup'

viewtopic.php?t=15666
Dec 08, 2006 subject: Question for BiPap users - UPDATED 12/14/2006