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[CPAP] Counter intuitive Data
#1
Question 
I have been using APAP (Resmed S9) for about 18 months now and tried four different masks.  I have also just started using the Sleepyhead software.  My thanks to all the good people who contribute so much to this forum and associated activities.

My problem is that my sleep experience runs counter to the Sleepyhead data.  My best nights sleep from a subjective point of view have definitely been with the Ciradience Sleepweaver Advance mask (the fabric nasal mask).  It takes a little time to eliminate the leaks around the mask before going to sleep but I am getting better at this.  What is more, as the leaks seem to mostly go into the eye area, it is impossible to ignore them - when one is not yet asleep in any case.  I normally have one or two waking episodes (visits to the facilities are required) and then awake refreshed.  This all seemed great to me until I looked at the Sleepyhead data which shows an increased API from less than one to about 2.5.  The large leak data is off the chart - showing at about 90% of the night I am experiencing large leaks.

By contrast my other masks fit well and easily when I first go to sleep.  However after about 4 or 5 hours sleep they all slip and leak.  Getting a good fit at this time is more difficult and often results in a running battle between me and my mask, with the mask usually winning.  I can lose a couple of hours sleep this way in a bad night.

My first attempt  to resolve this problem was to buy a chinstrap for use with the Sleepweaver in the hope that it might be caused by an open mouth.  This does not seem to be the case.  Large leaks remain with the Sleepweaver.  Worse still the other masks do not fit particularly well over the chinstrap - although in all truth I am not sure that the chinstrap is required with the other masks.

Now I have no problem with going back to previous masks or to buy another new one. But before I do this can I ask the experienced posters out there whether there is a problem with the data produced by the Resmed S9 and analysed by Sleepyhead when a Circadience Sleepweaver Advance mask is being used?  One piece of sleepyhead data in particular is confusing me.  The pressure (not mask pressure) does not go above 9 (Resmed S9 is set to automatically adjust between 4 and 20)  over the night.  Now by my reckoning if there is a prolonged large leak would not the pressure being put out by the pump be elevated to cope with the leak?
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#2
The auto CPAP is designed to maintain pressure and respond to your events increasing or relieving pressure as indicated by your respiratory volume, flow limitation, snores and apnea. A leak does not increase pressure, it increases flow to maintain pressure.

I would encourage you to consider setting your minimum pressure near your median pressure requirement. You will get better results, and more comfort. Just because the default minimum and maximum is 4-20 does not mean those are particularly good settings to use.
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#3
Yes, the older machines gave you the impression that they increased pressure, but it was flow they increased, but they kept adding more and more until you were in a hurricane!
The new machines are a little better, if you are at 9, they will increase flow to maintain 9 but at the same time they will not keep pumping in more flow if it can't be maintained at 9, so the newer machines are a bit better and might even drop the pressure then build it back up to try get a good seal. So if you are getting a good nights sleep with the cloth mask, use it, try to stop the leaks, but in the end, if you are fighting other masks for an hour or two, it is not worth it, If the machine is making up for the leaks and you are getting a good nights sleep, go for it.
Don't worry to much about a leak, if you feel better in the morning and you feel refreshed, that is what you need, not a 0.0 AHI.
If you feel good, that is what it comes down to in the end. Chasing for a low AHI is not all the answer. I have had a o.o on quite a few mornings now since I got a new machine, I can honestly say, I feel better when the AHI is around 1.1 how ut comes up with that figure I don't know. If it is a low figure you are getting, don't worry to much about getting it to 0, most normal people do not have that anyway and they do not have Sleep Apnea. Leaking into the eyes is not good though and if you can improve that it would be even better for you.
I don't know about over there, but in the UK you can buy sticky foam, gel patches to go over the bridge of the nose to help with leaks around the eyes and the top of the cheeks.
Anyway, have a good nights sleep and let the machine worry about keeping up the pressure.

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#4
My (albeit short) experience shows that I often get lower AHI when I have bigger leaks. I believe it was Walla Walla who pointed out that if the leak is large, the CPAP potentially can't "see" the obstruction, so the AHI number would not be reliable.

IME, my APAP and SleepyHead highlight the same leak data differently. My APAP doesn't tell me a whole lot. SleepyHead tells me plenty, and where I need to focus. I can feel as though I didn't have hardly a leak all night—and get a green smiley face from the APAP—and find significant leaks on SleepyHead. I believe SleepyHead, and the graphic presentation of e.g. leak timing is extremely important to me in optimizing treatment.
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#5
Hi Alan Speed,
WELCOME! to the forum.!
Good luck as you continue CPAP therapy, hang in there for more responses to your post.
trish6hundred
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#6
Smile 
Many thanks. I guess I was confusing pressure at the mask with pressure at the pump.  Clearly the other factors that you mention must play a role too.

I will try your advice and raise the bottom pressure to nearer the median also.  That sounds like pretty good advice and not something that I would have thought of.
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#7
Thanks sleep2snore that is encouraging and helpful advice.  Intuitively it seems as though any machine will have difficulty spotting AHI if there are big pressure drops caused by leaks of some sort so the AHI data might be a bit rough and ready.  I also agree totally about the APAP data about mask fit.  I get a smiley face when the mask is leaking badly so I have stopped using that particular piece of data.

At the back of my mind I am still not convinced that a mask which appears to be sealed properly when I go to sleep and when I wake leaks so much when I am asleep.

In the meantime I will bear your words in mind and use the sleep weaver when it suits me to.
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#8
Sorry Halfasleep.  I conflated my response to your advice with that of sleeptosnore.  Very helpful advice and I am very grateful.

I will get used to this board pretty soon I am sure but in the meantime I'll plead deteriorating mental capacity.
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