(05-02-2016, 05:12 PM)Ed1101 Wrote: I have seen several posts that indicate that too high pressure may produce centrals and that too low leads to excessive Hypopneas.
After 3 month on APAP therapy at 15 -20 pressure w/EPR=3, my 30 day average OI=0.24, HI=1.94, CI=1.27. AHI=3.45.
My doc reduced the pressure to 12-19 w/EPR=off last week (included in last 30 days). Now past week OA=0.0, HI=5.93, CI=0.87. AHI=6.79,
This is a good example of "If it ain't broke don't fix it."
Why did the doc feel compelled to lower your pressure and tell you to turn the EPR off? Were you complaining about the difficulty of breathing with the machine? Were you saying anything about feeling like the machine was rushing your breaths?
I ask because given those numbers at 15-20 with EPR = 3, there was no a priori
reason to mess with the pressures at all. And unless you were complaining specifically about the way EPR feels, there was no good reason to tell you to go from EPR=3 to EPR=OFF.
Quote:AS expected CI went down, HI went up and OA no impact. 90% pressure 30 days = 16.18, last week 90% p=15.54
The difference in 90% pressures is probably not statistically significant. But with a lower min pressure of 12, the machine has to do a lot more "chasing" events (and flow limitations and snoring) to get the pressure up to the level where it effectively keeps your airway open. When the min pressure was set to 15, the pressure was already high enough to prevent most of your OAs and Hs from occurring. Now that the min pressure is set to 12, a lot more Hs are getting through while the machine is reacting
to them by increasing the pressure from 12 to 15. And the machine is also probably lowering the pressure back down to the point where it no longer effectively keeps your airway open, and that also lets more Hs occur.
It's also worth pointing out that the reduction in OAI from 0.24 to 0.0 and the reduction in CAI from 1.27 to 0.87 is probably not statistically significant. But the increase in HI from 1.94 to 5.93 IS statistically significant. And it's a change that's in the WRONG direction.
Quote:Would it be worthwhile to increase the pressure min up to 14 and keep EPR off for next week to see if the Hypopneas go back down and the CA, OA remain low? Is there a so called sweet spot for pressure?
Yes, there is often a sweet spot for pressure. That sweet spot depends on each individual's airway.
I think that you should increase the min pressure back up to 14 and see what happens.
I also would say this about EPR: If you are more comfortable
with EPR turned OFF, then leave it off. But if you were more comfortable with EPR = 3, then turn it back on. The numbers when you had EPR = 3 were fine---as long as you are sleeping well and starting to feel a bit better.
You have to keep this in mind: Until you are sleeping well
with the machine, you won't feel much better. If a particular change in settings makes you more comfortable and keeps the AHI < 5, you can concentrate more on how you are feeling
than on chasing a super low AHI.