AutoSet vs CPAP, EPR and questions about my stats

hi,

Since I got rid of my brick 2 weeks ago and got a S9 autoset it's made a world of difference. My old brick had me on a constant pressure of 14 with a full face mask. My new S9 is on AutoSet throughout the night and the pressure rarely gets close to 14. I am also using I am nasal pillows (Swift FX) which is much more comfortable. I did have to get a chin strap because I open my mouth during sleep but overall, it's been night and day. From fighting pressure 14 with a full face mask and barely be able to sleep to all of the sudden, not even think about my mask and sleeping more deeply than I have in years.

Here are my average stats so far:
Average Hours per night: 8:03
Compliance: 100%
AHI: 1.27
Obstructive Index: 0.09
Hypopnea Index: 0.60
Clear Airway Index: 0.57
Average Leak Rate: 2.19
90% Leak Rate: 8.40
% of time above Leak Rate threshold: 1.62%
Average Pressure: 7.27
Min Pressure: 4
Max Pressure: 13.70
90% Pressure: 9.74
Average EPAP: 7.27
Min EPAP: 4.00
Max EPAP: 13.70

And here are my questions:
1) Do you see anything wrong with my stats? I have only seen my own stats so I am not sure if all these values look good or not (for example I was wondering about the leak rate)
2) Why would I ever want to set my CPAP machine to a constant pressure since AutoSet seems to work great (at least that's how I read my stats)?
3) There is an EPR mode on my machine that has been turned off so far. I am thinking about turning it on... has anyone used it? Any feedback?
4) just a general question: what exactly is 90% Pressure? Is it the max pressure during the lowest 90% recorded?
5) how about the 90% leak rate?

Thanks in advance!

franck-

EPR...."has anyone used it".
viewtopic/t105472/Poll-Do-you-use-quote ... chine.html

LSAT wrote:EPR...."has anyone used it".
viewtopic/t105472/Poll-Do-you-use-quote ... chine.html

Thanks I'll check out that board!

Stats look good.

90/95% numbers of anything just mean you were at OR BELOW that number for 90/95% of the night.
People tend to forget the "or below" part of the definition.
Sometimes these % numbers can be misleading though...like I once had a 95% leak number of 27 L/min which on the surface might look like I spent a large time in large leak territory but in reality on that night I only spent 30 minutes in large leak territory and the bulk of it was just under 30 L/min. So I take the % numbers with a grain of salt...sometimes they are useful and sometimes they don't tell us the whole story.

Your "numbers" look great and even more importantly you seem to be happy and doing quite well.
Your leak number to avoid is 24 L/min and your 8.40 L/min 90% number means you were well below large leak territory.

% of time above Leak Rate threshold: 1.62%

This just means for 1.62% of the night you were above 24 L/min. Part of that could be mask refitting or part just could be mask movement or even a little open mouth leak but it's well within acceptable limits.
ResMed won't even give you Mr Frowny face until you hit 30% of the night in large leak territory.
As long as the leaks don't wake you up I wouldn't be worrying about them if this is all the big leak you are seeing.

Why would you ever want to use cpap mode? Some people find the changing pressures in apap mode actually disrupt their sleep so in that situation cpap mode or a tiny range might be indicated. Also if maybe the higher pressures cause aerophagia sometimes we compromise and use a tiny range or cpap mode at a level just below what causes aerophagia issues.
Otherwise if you are sleeping great and feeling great then there's no urgent need to use cpap mode.
For some people it is actually a better deal anyway....like myself because I often need a LOT more pressure in REM stage sleep than I do in non REM sleep. Same could be said with sometimes sleeping on one's back vs one's side.
If the changing pressures aren't bugging a person....let the machine do its job and then we don't worry about any one pressure to use.

FranckDG wrote:1) Do you see anything wrong with my stats? I have only seen my own stats so I am not sure if all these values look good or not (for example I was wondering about the leak rate)

Your stats are EXCELLENT and, just as importantly, you write:

and sleeping more deeply than I have in years.

So keep up the good work!

2) Why would I ever want to set my CPAP machine to a constant pressure since AutoSet seems to work great (at least that's how I read my stats)?

In light of the facts that you are sleeping better than you have in years AND your current stats are excellent, I can't imagine any need to switch back to CPAP. Some people are bothered by the changing pressures, but you aren't. So there's no need to switch from AutoSet to CPAP mode.

3) There is an EPR mode on my machine that has been turned off so far. I am thinking about turning it on... has anyone used it? Any feedback?

EPR is a "comfort" feature. If you are curious, sure, turn it on and experiment. You may find that you really like it. Or you may find that you prefer it turned off. There isn't a right/wrong answer that applies to everybody when it comes to EPR. That said: Since EPR reduces the pressure on exhale by a fixed amount on each and every exhalation, a few people find that they need to make a corresponding increase in the pressure level to keep the apnea under control. If you find that you prefer the feel of EPR turned ON, but then your AHI noticeably goes up, you can cross the bridge of what to do at that point.

4) just a general question: what exactly is 90% Pressure? Is it the max pressure during the lowest 90% recorded?
5) how about the 90% leak rate?

As pugsy explained, the 90% numbers are the levels at 90% of the data is AT or BELOW. Since your 90% Leak Rate is 8.4 L/min, that means that for 90% of the night your (unintentional) leak rate was AT or BELOW 8.4 L/min. Since Resmed defines a Large Leak as 24 L/min, we know that your leaks were well under that level for at least 90% of the night. Since your % of time above Leak Rate threshold =1.62%, we know that your leak rates were AT or ABOVE 24 L/min for 1.62% of the entire night. Resmed's Mr. Frowny Face shows up on the LCD only when the leaks are above 24 L/min for at least 30% of the night.

My interpretation of your leak numbers is this: There's a tiny bit of serious leaking going on---i.e. your Large Leaks make up 1.62% of the night. But unless the large leaks were actually bothering you---in the sense of waking you up or making you restless---they're not lasting long enough to worry about. I'd watch the % of time above Leak Rate threshold for the time being. And personally, I wouldn't worry too much about Large Leaks unless that % of time above Leak Rate threshold gets to be consistently above about 10-15% as long as the leaks were not disrupting my sleep.

You can learn more about the statistical meaning of 90% numbers by going to my blog entry Average, Median, 95% numbers: A guide to those who don't remember their introductory stats