cby1 wrote:*Sigh*. Here's another of many shots that show a similar phenomenon with almost no leaks. Leaks are not the rule. My original post asked the questions, but I'll spell them out.
1. Is this Flow Limit chart "bad" - especially when my CPAP is maxed at 20 cm at the time?
Perhaps. It depends on whether those FL are "real" or are artifacts that are being created by the pressure. Sludge used to occasionally post on this idea---that some people's breathing can become a bit less stable when too much pressure is applied.
2. Does this pattern of low AHI and high FL suggest some "residual UARS" after the events have been dealt with?
Maybe. Maybe not. See #1.
3. General reactions, given my complaints - can someone *other than avi* weigh in please?
Well, I'm not avi, so here's my two cents. You also write:
I've been assuming that it's been something "non-CPAP" (psychological, medication, sleep hygiene) - and maybe it is.
Because of this statetment, I'd also continue looking at several other potential causes of your current situation.
First: Non-OSA related sleep problems.
Any reason to believe that you are waking up a lot during the night? Any sense of spending a lot of time tossing and turning and semi-awake? How long does it take you to get to sleep at night?
On the night you posted the data, you apparently didn't go to bed until 3:15 and you got up at 9:50. That's only about 6 1/2 hours of machine time. Any chance you just need
more sleep? Have you tried pushing bedtime back to 2:15 or 1:15? What happens when you go to bed earlier?
Since you mention "sleep hygiene" as a potential problem, that's something else we need to give serious thought to, particularly in light of the fact that on the night you posted, you got to bed very late and only slept for at most 6 1/2 hours.
Do you have a regular sleep schedule? If so, what's it look like?
How much caffeine are you consuming? What about alcohol?
How much daily exercise do you get? Do you get outside in the daylight for at least a few minutes every day? If so, when?
Do you spend a lot of time reading, watching tv, or web browsing in bed? Do you build in some "down time" before going to bed each night?
Second: Lifestyle considerations.
You mention "medication" and "psychological" as potential factors in how you are currently feeling What medications are you on? Any of them new? Any dosage changes?
Any excessive stress in your life? If so, is there a way to manage it?
Are you eating well? Are you taking care of yourself? Do you get enough exercise?
Finally: CPAP tweaking
Definitely bring up the idea of RDI and RERAs with the new sleep doc on 12/7. Also specifically ask the doc about your concerns about how much time you are spending at 20cm and whether a bilevel that can go to 25cm is warranted.
But also keep an open mind to the idea that it may be possible that your airway is not responding as expected to the high pressures. As I mentioned earlier, Sludge used to occasionally post on the idea that too much pressure can cause airway instability and that sometimes the answer is less pressure rather than more.
On the night you posted the data for, the lowest parts of the FL graph seem to correspond to places where the pressure has been decreasing for a while. Now it could be that the max pressure finally started stabilized the breathing OR it could be that the breathing actually started to stabilize after the pressure went down. It's difficult to tell from the "all night" picture since we can't see the individual breaths at this scale in the flow rate.
It might be useful to show close ups of the flow rate, pressure, and FL graphs for the following time windows:
4:30-4:45
4:45-5:00
7:40-8:00
Note: I don't want one picture from 4:30-5:00 because that's too much time to really see the shape of the inhalations in the flow rate graph. So please break it up into 4:30-4:45 and 4:45-5:00. And we need to see flow rate, pressure, and FL graphs.
Looking at some of the individual inhalations that are being flagged as "flow limited" may help give us a better idea of whether the FL are real or artifacts.
If you are wanting simple tweaks:
Try PR's suggestion of turning EPR up to 3cm and see what happens.
Try narrowing the pressure range. You might try using 15-19 for a few days. If the number of obstructive events does not increase AND there's any improvement in the FL curve, you could then try using 16-18 for a few days to see if things get better or worse.