(07-29-2014 03:53 PM)StephenR Wrote: so here is a response from my sleep tech on the stats I sent her:
"you have to remember these app sites are not true reflections of your therapy efficacy. Manufacturer software program have specialized algorithm to measure your indices.
There is some truth to this. Neither the Resmed FOT nor the PR PP algorithms are the same as scoring CAs on a real PSG. Nonetheless, your data is showing a lot of CAs scored and it would have been useful for the tech to have actually looked at some detailed
data as well as the summary data you post.
Quote:It is common to have elevated CA's on CPAP, this is due to the exchange of gases that is occurring now that didn't previously. With a set pressure and time on therapy, CA's will stabilize. Also, remember there is night to night variances and occasionally you can have a night with increased CA but it is usually not long term.
This is also true. But the question is what does "long term" mean to the tech. you've been PAPing now for over a month and usually if this is all that's going on, the CA will start to go (way) down by the end of the first month or so.
Quote:I looked at each of your nights usage from July 23-28th, with the exception of July 27 & 28, your CA levels have been good (<10). The fact that your CA's are not constantly elevated means this is not Central Apnea.
First statement SHOULD be questioned: Why is the tech choosing to draw the line at a CAI = 10 rather than 5 given that you are feeling exhausted and sleepy?
Second statement probably is true: If you really had a problem with Central Apnea, your CAI probably would have remained exceptionally high on every single night. Unless there's a pressure threshold that is triggering the CAs, and you only go over that threshold sometimes
. And in that case, what you are looking at is more properly called Complex Sleep Apnea rather than Central Sleep Apnea.
Quote:I will lower your pressure as your obstructive closures are within normal range and see how you feel after a few nights."
This IS a reasonable thing to do. If the CAs are being caused by pressure, lowering the pressure should reduce the number of them. If the number of OAs and Hs does NOT go up when the pressure is lowered, then that's evidence that you were overtitrated in the first place, which is not that uncommon.
But here's the thing that I wish you had asked the tech to do: I wish the tech had looked at the detailed Flow rate data from one or two of the good nights and compared it to one or two of the bad nights.
In other words, I wish the tech were looking at something other than just the summary data for each night. Because:
1) Sometimes a lot of CAs can be scored at the beginning or end of the night when you're not really sleeping, but you're also only half awake. Likewise sometimes you see clusters of CAs at times when you remember being pretty restless during the night and "fighting" to get back to real sleep. These kinds of CAs would probably NOT be scored on a PSG (because you're not really asleep). And in this case, the best thing really is to assume that the CAs will likely disappear as the PAPer becomes more used to the equipment and starts falling asleep more quickly and more readily with PAP experience. And in this case, the continuing fatigue, exhaustion, sleepiness and/or brain fog may point to additional factors that are causing bad sleep
now that the OSA is technically under control. (Real CAs are not part of obstructive
2) Sometimes real
pressure induce centrals can be spotted from analyzing the Flow data that shows every breath you took. If there's a 30 minute (or more) period of waxing/waning breathing with CAs scored at the nadir of the cycle and it's not at a time when the person was apt to be semi awake, it's worth looking much more closely at the data on other nights for the same pattern AND it's worth listening to the patient's complaint that the exhaustion, fatigue, sleepiness, and/or brain fog is not getting better OR is getting worse. Because this is the kind of pattern that might not
simply get better with time. Prudent watchfulness of the data may be reasonable for another month or so, but if these kinds of patterns continue on more nights than not for 2 or 3 months, its time to start thinking about whether another sleep test is warranted so that if Complex Sleep Apnea might be a real issue that needs to be addressed by changing the PAP machine itself. And note that Complex Sleep Apnea is NOT the same as Central Sleep Apnea.
In other words, examining the Flow graph itself can go a long way in figuring out how likely the machine scored CAs are to be the real thing.
So if you want other patients' opinions on what your data looks like, you could post the Flow rate data from a good night and a bad night.