Apnea statistics question, how tightly controlled is your apnea?

[happydreams]

@Gideon, thanks for the RERA wiki link.  So it seems, at least by the examples, that RERA is only inspiry related?  There's no respiratory distress associated with reduced exhalation?  Or that there's no name for it?

In the Details>statistics window, would the median entry be simply the median of the flow limitation signal over the entire duration of the sleep interval?  I think that's what I gathered from my reading.  Is this effectively a density function, i.e. one takes the session time into account?  My observation (not a criticism!) is this may de-emphasize reporting flow limitations for the cases where flow limits were non-continuous.  (Relatively sparsely separated flow limitations)  For long, continuous limitations, it appears to be a very good metric.

At the moment, I can't quite think of a better metric, but for folks like me, with sparser flow limitations, it seems to de-emphasize flow limitation parameter, when in fact we may have a lot of low level flow limits.  Another way of looking at is that one has run out of dynamic range to express the parameter within the fixed number of digits.  Having worked in radar, it is common to abandon linear scales for log scales, as it's nearly impossible to express the numbers any other way.  Log scales are funky to read at first, but they are very compact ,and convey the essential information.  

This conversation has been very helpful to further understand the issues.  Thanks to everyone that has contributed.  If there's more statistical information that we can discuss here, I'd be quite happy to continue.

[Gideon]

Most of what we see is inspiratory in nature, there is the occasional expiratory issue such as the palatal prolapse that we have had issues tracking.
On the median FL info, we use it strictly as an indicator.

[Sleeprider]

We were talking about this particular shot. What I see is some variable tidal volume leading to a really big sigh, followed by a quick return to zero flow that looks like a swallow, followed by continued expiration from that big breath. Things are a bit ragged, and it looks like a snore at 12:49:30, then resumption of normal respiration. There is not a significant flow-limited breath here. There may be an arousal, but not RERA.  I think I see a flop in position.

[happydreams]

I had picked that sequence a little arbitrarily, thinking it may be something.  It's just a small blip relative to the rest of the breathing activity.  

@Sleeprider, You are very experienced, and I am amazed you could pick out that from the waveform.  

As it turns out, I had some video of that time.  I just looked at it.  What happened was, I kid you not, I elevated my body, bending from the waist up about 30-40 degrees, then lowered myself and flopped on my side.  I most probably held my breath during part of it.  I don't know, that was one heck of a lot of motion.  I don't see how there wasn't an arousal of some sort.  

Sorry to have drifted off my own topic.  So RERA's appear to be inspiry only.  A different sequences I found showed increasing less area under the curve in expiry leading to a recovery breath.  It seemed similar in nature to RERA but for expiry, which was the basis for my question.

[ICEMAN]

Look at titration principles, what do they try to accomplish.  The goal of titration is ultimately to "Optimize" therapy settings.  
Do note that most labs just look at which settings produced the best results in a very narrow window of time and call for those settings.

1. EPAP eliminates OA, increase EPAP to eliminate OA, yes even on CPAP
   
2. Increase PS/IPAP/EPR, leaving EPAP as determined in step 1, to eliminate H, FL, RERA
   

For CA in the "lucky" people, this is just for CPAP/APAP/BiLevel without other complicating issues

1. Increased PS typically increases CA so Lower PS/EPR to decrease CA events
   
2. Higher Pressures tend to increase CA so Lower Pressure (EPAP) to reduce CA events
   
3. Pressure variability tends to increase PA so lower PS/EPR/Flex to reduce variability and thus reduce CA events
   
4. Narrow the pressure band limits (Min/max pressure, Diff between min EPAP/Max IPAP) to approach a single pressure therapy, approach CPAP therapy wo EPR/PS/Flex
   

With CA present, always look for a balance between OA and CA.  This frequently is the point of lowest AHI but as CA goes down OA goes up.  The actions to reduce obstructive events tend to increase central events and vice versa.

Hi Gideon,   Hm to me your post serve for me very handy educational reference, PAP treatment summary