09-20-2019, 12:28 PM
(This post was last modified: 09-20-2019, 12:38 PM by mtwomey.)
APAP leak cycle
I'm a new CPAP user with a resmed 10 auto. I'm only a couple of weeks in so far and have generally had surprisingly good success (since I know it can be challenging to become used to CPAP and so forth, I guess my expectation we're low for the "starting out" time period).
Anyhow, I'm using an Airfit 30 mask and tracking things with OSCAR. I love looking at the data and I've noticed what seems to be a "cycle" with leaking.
What seems to happen physically is that I go to bed and everything is fine until maybe 4 or 5 in the morning. Then sometime around there I'll get a bit of a leak that wakes me up. At this point - it seems like the machine is increasing pressure in order to compensate for the leak. However - this means it leaks even more! So I have to *really* tighten it up a lot to stop it. In short: leak -> increase pressure -> more leak -> have to make it real tight.
I'm guessing this is a common issue and there are probably some good strategies to help with it. Right now my min is 8 and max 20. Without leaks I top out around 13. One thing I was thinking was to set my max there (or near there) so that it doesn't shoot up to 19 or 20 like it's been doing after leaking for a while.
Wanted to get thoughts from those more experienced.
RE: APAP leak cycle
(09-20-2019, 12:28 PM)mtwomey Wrote: I'm guessing this is a common issue and there are probably some good strategies to help with it. Right now my min is 8 and max 20. Without leaks I top out around 13. One thing I was thinking was to set my max there (or near there) so that it doesn't shoot up to 19 or 20 like it's been doing after leaking for a while.
Probably the best strategy other than trying new masks.
09-20-2019, 12:51 PM
(This post was last modified: 09-20-2019, 12:53 PM by sheepless.)
RE: APAP leak cycle
I had that problem when I was using a resmed autoset. only thing I could do is shut the machine off to reset it. with asv, we use a forceful 'blow back' exhale to reset runaway pressure. I didn't know about that before asv so I never tried it. IDK if it works on apap but you might try it. as you suggested, limiting your max pressure will probably solve the problem for you. personally I'd set it 2-4 cmw above your max of 13 and work my way down if it's not enough.
RE: APAP leak cycle
Unfortunately the blow back does not work for APAP machines only the ASV. It looks like positional apnoea is causing your obstructions to rise so the machine raises pressure to clear the obstructions which causes leaks, I wonder if you roll onto your back at that time in the night
RE: APAP leak cycle
Is there any particular reason your top limit is at 20 cm? Even at the worst of instances of leak and pressure rise in the two days you show, you don't really exceed 18 cm. If...IF...these two examples are truly representative of your typical 'troubles', you may profit from an experiment where you set the top at 17 cm and see what happens for two or three nights. This should be done only after you have figured out how to control leaks.
Leaks can be caused by excessive pressure for the fit, but also by deformation and deflection of either the headgear or the mask/cushion. That your leaks happen later, I'm wondering if you tend to sleep in one position mostly until the later hours and then turn on your side, or on your back where your chin tucks a bit (you do have some persistent events showing, mostly later on where your leaks start to give you trouble).
RE: APAP leak cycle
If you feel that the only way to reduce leaks with the mask you have is to go very tight, some aspect of the mask, frame size, cushion size, etc. isn't right for you. I'm guessing you're tightening to the point that it's either uncomfortable or painful. If that's true, something with the mask needs to change.
Positional aspects should be considered also. Some pillows can hinder side sleeping by pushing the mask around causing leaks. The lack of hose management can have the hose pulling the mask, again causing a leak.
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RE: APAP leak cycle
I'm going to suggest a different route. Resmed''s are notorious for going to the maximum programmed pressure when flow limits are detected. Also, your pressure settings allow for big swings and are sometimes more annoying than a small apnea. Based on my previous observations, I would recommend that you set the pressure range to 11cm minimum and the maximum to 16cm. I would set the EPR to 3cm full time. I don't recommend the use of any ramp. If this proves promising, we can hopefully narrow the pressure bandwidth. You might experience some CA's but that is to be expected. When you adapt to the pressure, they should decline.
I hope this will get you some restful sleep. 
RE: APAP leak cycle
What really helps me when I get leaks from moving around or bumping my mask, instead of adjusting straps I just pull the mask straight out from my face a bit , let the soft mask rubber seal flex a little, then release my hand from the mask. Sometimes the seal just needs to reseal itself against your face.
09-20-2019, 04:18 PM
(This post was last modified: 09-20-2019, 04:20 PM by mtwomey.)
RE: APAP leak cycle
Thanks guys - these are great ideas!
The image I attached is fairly typical of most nights (so far). I generally sleep most of the night on my side with occasional rotations onto my back. It does feel to me like some random incident gets a slight leak going (like I rolled badly, hose pulled, ...etc) and then from there it start the cycle I described. So yes - what I don't like about tightening it that way, is it's uncomfortably tight (not painful, but pretty dang tight).
Without a leak, the pressure has never gone above 14, so I like the idea of trying a bit of a tighter range. I also like the idea of "pulling" the mask away for a moment and letting it kind of "reform" itself and reseal. I will try that as well.
I have very little experience with masks, this is the one I started with. I did however have a CPAP nearly 20 years ago with a full face mask for a few months. I really like this particular mask so far - I like the nose part where I can see, wear glasses easily ...etc. I also find it comfortable - so I'm hoping I can solve it without starting on a process of trialing other masks.
(09-20-2019, 02:19 PM)Crimson Nape Wrote: I would set the EPR to 3cm full time.
One question on this part: Currently, I have this set to 1cm full time. I don't really have any exhale pressure problems / uncomfortableness. Is there a potential benefit to increasing it to 3cm?
RE: APAP leak cycle
Yes, It can reduce flow limitations and increase your tidal volume. This may help to eliminate some of your pressure increases. The worst thing that can happen is it doesn't work for you.
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