Pressure Question

[TheTwinsMom1]

I recently switched from using straight CPAP to an APAP. We currently have it set to 6-10, and at my titration sleep study they said I needed a pressure of 8. However, on the APAP, It appears my 95% pressure is 9.9. Would you change the APAP to 6-12 and see if I am really needing a higher pressure?

Here are my stats from the machine:

Product: S9 AutoSet
5/24/2010 - 5/25/2010
Device Settings

Therapy Mode: AutoSet EPR: Full_Time EPR Level: 2.0 cmH2O
Minimum Pressure: 6.0 cmH2O Maximum Pressure: 10.0 cmH2O
Pressure - cmH2O
Median: 7.7 95th Percentile: 9.9 Maximum: 10.0
Leak - L/min
Median: 0.0 95th Percentile: 0.6 Maximum: 9.6
AHI & AI - Events/hr
Apnea index: 0.6 AHI: 0.6 Obstructive: 0.6
Central: 0.0 Unknown: 0.0 Hypopnea index: 0.1

Usage
Used Days >= 4 hrs : 2 Used Days < 4 hrs : 0 % Used Days >= 4 hrs : 100
Days not used: 0 Total days: 2 Median daily usage: 7:17
Total hours used: 14:34 Average daily usage: 7:17

I am not sure how to attach the actual detailed graphs to my post, but they show me having about 4 long episodes each night and that is when my pressure goes up to try and deal with those. My leak is low, and I am not sure what Minute ventilation and flow limitation are.

Thanks

[KatieW]

If it were me, I would have my minimum pressure closer to the 95%. Look at your detailed graphs, in a 5 minute view, and see what your pressure was just before each obstructive apnea, and after. If you were hitting your maximum before the OA, then I would raise the maximum, maybe by 1 cm.

I found that my minimum pressure of 10 is higher than my titrated pressure of 7, but I use EPR of 2. Also I am getting more REM sleep now, than during my sleep study.

On ResMed machines, using EPR decreases the exhale pressure for the whole exhale, so you need to raise your pressures to compensate for that. While ResMed does suspend EPR, for decreased flow, snores or apneas, I don't know how fast that response is.

Rested Gal has given great explanations of how EPR works, if you a search for her threads.

And here's a good explanation by Dave21:

viewtopic.php?f=1&t=50331&st=0&sk=t&sd=a

[TheTwinsMom1]

Thanks for your post. I did not account for the EPR which is set to 2. So I will try setting the machine up two to account for the EPR and see what happens. I knew something was not all the way correct when using straight CPAP at 8, I was still waking up really tired after 60 days of trying it. So I am now in that tweaking stage.

[Big Daddy RRT,RPSGT]

If you are "topping out" you might try a higher pressure. If you feel comfortable you can also raise the starting pressure so you don't waste sleep time on ineffective lower pressures. Good luck!

[rested gal]

I think it's the lower pressure setting you need to raise, rather than the upper pressure, TwinsMom. But I'm not a doctor!

Or maybe raise both.

Here are links to some of my thoughts about EPR and about range setting for autopaps in general:

Cflex 1-3 Levels - topic started by jucs
January 2, 2010
viewtopic.php?p=436272#p436272

Although that topic was about C-Flex in a Respironics machine, I also wrote about EPR used by ResMed machines.

______________

The importance of the minimum pressure setting with an autopap:

Results: 1st night with Auto A-Flex (topic started by TSSleepy)
Two nights graphs posted using pressure range 4 - 20 and 10 - 20
viewtopic.php?p=348963#p348963

November 2008 Just got an APAP (topic started by turbosnore)
viewtopic.php?p=319619#p319619

October 2008 Turning off Aflex and Cflex (topic started by DoriC)
viewtopic.php?p=307265#p307265

September 2008 New Guy - Need Help w/Settings (topic started by alanhj13)
viewtopic.php?p=294319#p294319

Wulfman, DreamStalker, and ozij explain why autopaps make changes slowly.
December 2008 Why adjust APAP. Isn't it auto? (topic started by oxygenium65)
viewtopic.php?p=323218#p323218

[TheTwinsMom1]

So if I am reading this correctly, due to EPR being on 2, I would want my minimum pressure to be 10 so that when it drops on exhale it is not going below my titrated pressure of 8? Wonder if I should set it to 10-20 for three or four days to get a good idea of what pressure is working best with the EPR.

[Sleeprider]

I think raising your minimum pressure to 8 will close the gap on your range, allowing the machine to respond faster,and start off closer to the pressure you need. As I read the results you posted, you are not experiencing excessive AHI events. Something we have learned to do is to make SMALL changes, and wait to see results before making further adjustments. If your snore rate is down, and you feel ok, that is a good sign combined with the AHI. The fact your 95% pressure is near the top of your auto pressure range really isn't a problem by itself. Elevating the top of the range 1 or 2 cm h2O is ok, but try not to make big changes all at once before observing their effect.

[JimIllinois]

It's as much art as science, getting things tweaked just right.

Too low is not good because the machine wants to drop back toward min after each correction. So, it ricochets between good and too low. Half the time you want more pressure and aren't breathing well, and half the time all is well.

Too high, with an auto machine, should only happen if your leaks get bad. More pressure is called for, which makes the leaks worse. In that case, you might go into a higher-higher-higher mode until the max is reached. You may be breathing fine, but making a lot of leak noises.

Bottom line, it's best if min and max are as close as you can get them and still have a comfortable restful sleep. My opinion only, of course.

Personally, I range pretty far, depending on whether I am on my back or side. So my min/max are 5 units apart, and I get awakened by leaks occasionally.

[sleepmba]

I would recommend turning the Min and Max up by 1 and see what you get. In a couple of days(nights) if you are still max'ing out. Go for another turn up and so on. This should give you some good data in order to tune your machine. Good luck!

[Big Daddy RRT,RPSGT]

TheTwinsMom1 said...Therapy Mode: AutoSet EPR: Full_Time EPR Level: 2.0 cmH2O
Minimum Pressure: 6.0 cmH2O Maximum Pressure: 10.0 cmH2O
Pressure - cmH2O
Median: 7.7 95th Percentile: 9.9 Maximum: 10.0
Leak - L/min
Median: 0.0 95th Percentile: 0.6 Maximum: 9.6
AHI & AI - Events/hr
Apnea index: 0.6 AHI: 0.6 Obstructive: 0.6
Central: 0.0 Unknown: 0.0 Hypopnea index: 0.1
Using these setting you appear to be well treated with AHIs less than one. Many people would love to have these numbers. But you are "topping out" so if your not sleeping/feeling great you might try increasing the max to see if you might benefit from more pressure. If you are pressure tolerant you could increase the min (starting pressure). Some people sleep better on the lowest pressure possible others do better starting closer to their 95th percentile. Maybe 2 below your 95th percentile pressure so 8cmH2O might be a better starting pressure? So maybe 8-12 cmH2O, starting a little higher and also giving your auto a little more latitude?

TheTwinsMom1said... Thanks for your post. I did not account for the EPR which is set to 2. So I will try setting the machine up two to account for the EPR and see what happens. I knew something was not all the way correct when using straight CPAP at 8, I was still waking up really tired after 60 days of trying it. So I am now in that tweaking stage.

You should not have to account for the EPR. It is designed to give you pressure relief when exhaling while still providing the set pressure. But there are other thoughts on this matter.

As for me, I was using a set pressure of 14 cmH2O and sleeping and feeling much better than being untreated but I still felt quite drowsy/sleepy everyday. So I got an Auto to try. After using the auto with wide open settings of 5-20cmH2O for about a week, my 95th percentile was about 14 cmH2O with an occasional max of 17 and I felt worse than I did on the set pressure.

So I tried 12-20 cmH2O for about a week. I was sleeping and feeling better than I had on the set pressure but the I was still feeling drowsy almost everyday. The pressure was riding the min (bottoming out) frequently so after about a week I tried 11-20cmH2O. After about a week, I felt a little improvement. I was still riding the min pressure and still feeling drowsy for short periods almost everyday out so I tried 10-20cmH2O. After a week I saw a significant change in how I slept and felt. I was dreaming a lot more and feeling much better. Now I feel good most days and have short periods of drowsiness on some days. This is the best I have felt in years and is the best I have ever felt on PAP (about one year of treatment). On 10-20 cmH2O I occasionally "bottom out" and only occasionally need more than 15 cmH2O. I could probably limit the max but I figure the pressure is there if I need it. My AHIs were the same on all these pressure settings about 0.1 to 0.4 most nights. I hope this helps you find your sleep zone.

[TheTwinsMom1]

Thanks Big Daddy your post was very helpful.

last night I ran it on 8-12 and I had a couple times where it went up to almost 12, but I only had 1 apnea instead of four. Also for the first time in forever, I slept all night long with no arousals. So I am feeling I am getting closer to my best pressure range. I was tired upon waking but I feel that is because I got to bed later than normal, lol.

[Big Daddy RRT,RPSGT]

Thanks Big Daddy your post was very helpful.

last night I ran it on 8-12 and I had a couple times where it went up to almost 12, but I only had 1 apnea instead of four. Also for the first time in forever, I slept all night long with no arousals. So I am feeling I am getting closer to my best pressure range. I was tired upon waking but I feel that is because I got to bed later than normal, lol.

That sounds like an improvement. Tell us how your week goes.

[Muse-Inc]

Am I the only one who thinks median pressure tells us something useful..am I mistaken? My median pressure ranges from 8-9 (very congested nights) meaning half the time it's under and half over. Since my APAP range is 7.4-15, half of my pressure is <8. My 95thcentile is consistenly 10.4 occasionally 10.8 (bad congestion), max at 11.something. AHIs is <1.3, AI typically 0. I am slowly increasing the lower pressure...my brain doesn't like change so I increase (0.2-0.4) & leave it there for a month or so before changing again..so far no change in numbers changing from original setting of 6-15. Multiple wakeups consistent so far, no improvements as I've been hoping beginning to think they're caused by something other than OSA or CPAP therapy.