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Thoughts on setting minimum and maximum pressures
(02-18-2014, 05:52 PM)3porpoise Wrote: Hi,
If I'm not mistaken , believe 95th percentile leak of 30.6 is too high is it not? Other more experienced members can comment on this but should it not be 24 or less ?
Can someone verify this please?
ResMed define acceptable unintentional leak at 24 L/m and prolong high leak above that number the machine cannot compensate or give accurate data reading. 95the percentile means leak was at or below 30.6 L/m for 95% of the time (not 30.6 L/m all night night long), of course the lower the better but because median leak is low at 2.4 L/m, leak in this case is not a problem (might be just adjusting mask fit, scratching/blow the nose, or even leaving the machine on while taking a pee which is better to turn machine off) as long as not getting close to the eyes or disturb my sleep
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Supposedly the magic leak number for Resmed is 24, and generally, I want my 95% to be under that (my max too if possible.)

BUT you have to look at the graph to see if you aren't just getting a few leaks that you are fixing during the night.

Preventing the leaks from WAKING you up or KEEPING YOU AWAKE is likely far more important in most cases than any arbitrary number.

My leak seldom goes anywhere near 24, even at max, but it drives me crazy if my pillow slips loose and air is blowing wildly.

The machines can keep up with quite a bit of leak and still deliver therapy but the noise and air blowing will bother more people before therapy breaks down.

Fix the leak. Don't agonize over it. The machines are DESIGNED to leak.

Which explains why Resmed and Respironics use radically different leak numbers -- Resmed subtracts the expected mask leaks, while Respironics works with "total leak" (somewhere around 60 is high for them but I don't use Respironics so don't quote me).

Sweet Dreams,

Sleep study AHI: 49 RDI: 60 -- APAP 10-11 w/AHI: 1.5 avg for 7-days (up due likely to hip replacement recovery)

"We can all breathe together or we will all suffocate alone."
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masks are what leaks
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(02-18-2014, 06:58 PM)me50 Wrote: masks are what leaks

I have investigated this in excruciating detail the last few days, and I have discovered it is not masks that leak, but rather one's face that leaks.

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lol retired_guy

the whole face leaks huh?
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To answer a couple of questions posted:
My prescribed pressure is 4-20 (I know not very helpful). My provider had me do an "at home" sleep study so I don't really have any good information. As my new Obmacare insurance doesn't cover DME I was on my own to purchase machine so I have no DME provider to consult with. As I mentioned in my original post I'm basically on my own.

The reason I brought my max down was that because when I woke at night the machine would go up to maximum pressure within two or three minutes which would then make it hard to sleep. My theory on the max is to keep it high enough that the machine can work and if you see the pressure hitting the max frequently to move it up.

Within the last week I have just started using the ramp feature with the minimum pressure set at 7.6 ramping up to 7.8 over 15 minutes. This basically keeps the pressure at this level for 15 minutes to allow me to go back to sleep when I wake up at night.

The minimum I have brought up to what seems acceptable to me from a not feeling suffocating level.

Although I would like my leaks to be lower, I think they are mostly related to me tossing and turning and knocking the pillows loose. I have yet to wake breathing through my mouth although I do were a chin strap to help prevent that.

The average pressure data I posted may be misleading (high) because of the above problem with the "run away" pressure increases. I just looked at the graphs for the past 30 days and if I ignore the "run away" events I fine the max pressure for the night to be between 10.5 and 11.5. Similarly if I ignore the intial low pressure getting to sleep I see the minimum pressure during the night to be between 7.0 and 9.0 (obviously the 7.0 was before I brought my minimum up to 7.8).

My real question, I guess is what are peoples thoughts on setting the minimum?

I can come up with two ideas on my own.
1) Set the minimum low (say 5 in my case) let the machine go as low as it can and increase pressure as the machine dictates.
The problem I see here is aren't you inviting apenas to occur? My logic is that we all know at pressure of zero we will all have enough apneas to require cpap. Presumably at some low pressure we will continue to have lots of apneas. Which leads me to my second idea.
2) set the minimum at some level that minimizes the "work" the machine has to do . In other words if the data shows pressures going from say 7 to 11 every night might it not be better to have a higher minimum to say 8 or even 9 to help minimize the events that cause the rise in pressure? Of course by this logic you could just put it in standard cpap mode and keep it at the top pressure.

Perhaps the real answer is I'm over thinking all this.

I guess I want to give myself the best chance of having cpap work for me and would like to set everything to optimum conditions. I realize that over the coming months time will tell, but I was hoping to learn from experienced users as to what worked or didn't work for them. Or any thoughts on things I'm not considering.
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if you want to keep your therapy on auto pressures, I would go with 7 (8 if you are more comfortable starting at that number) to 14 for a week or two and not change anything else and watch your data. if you make changes in pressure or anything else or don't keep those pressures for at least a week, it will be hard to see trends that can help you make better decisions. Also, if your insurance doesn't cover DME equipment and supplies, will it cover a doctor appointment to a neurologist or some other doctor that can help you with this? Just some thoughts.
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(02-18-2014, 01:30 PM)tahoemark Wrote: Over the last month I have brought up the minimum pressure to 7.8 and lowered the maximum to 12.0.

I'm still not sleeping great nor have great energy but I think it is improving.
Over the last 30 days my median pressure was 9.1, 95th percentile 11.4. My average AHI is 1.7. My median leak is 2.4 and 95th percentile 30.6
Two comments:

1) The 95% leak percentile is high enough to make it worth looking at the leak line as a whole. It could be that you only have large leaks (above 24 L/min) for a short period of time or it could be that you've got some significant leaking going on for 30-40% (or more) of the night. Does Mr. Green Smiley show up in the morning or does Mr. Red Frowny show up?

2) You say that you think your energy levels are starting to improve. It can take time and even though you're more than a month in, you may still be adjusting to therapy and your body may still be healing from the years of less than restorative sleep. It can take some of us several months before we notice any real difference in how we feel. You may want to keep some kind of a journal so that you can track how you're feeling each day to determine whether you really are starting to feel better.

So it seems to me that you probably should leave your pressure settings where they are at for now and focus on figuring out whether you've got a leak problem.
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Me50 the only reason I keep the maximum pressure relatively low is that I have a problem when I awake during the night and try and get back to sleep the pressure will go to the maximum when I'm awake which makes it hard to go back to sleep. For example last night the highest my pressure ever got while sleeping was 10.7 around 4:40 I woke up at that time my pressure was 9.4 within the span of about 2 minutes it went up to 12 (while I was awake). But I take your and others advice leave everything alone for awhile and see what the trends are. Also I could see a neurologist or some other type of doctor. Not sure where I would start or what the right type of doctor is, any thoughts?

robysue, I've read many of your posts and always find them thoughtful. I am concerned about my leaks, however it appears to be mostly short term events. Let me give you some data from last night, which was not a great night but fairly typical. According to sleephead my average leak was 7.43 and 95% was 37.2. Looking at the graph I see about a dozen instances where it spikes from 0 up to the 15-25 range most of these are a duration of under 15 seconds, however 3 of them were in the 2 minute range. More worrisome is that I had about 9 events going up to the 30-45 range these typically were in the 5 minute range. I'm not sure what to make of this. As I said I don't think I'm mouth breathing, I am aware that I jar the mask from time to time and have to reset it. Any thoughts for how to monitor this? What to look for?
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Oh, I forgot to mention I do get Mr Green smiley face ever morning.. don't know how that is determined and/or if it means much.
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