Originally,10 years ago I was tested for OSA and the AHI was 33. I had problems using the CPAP device, so I quit. I restarted about 2 1/2 years ago with a Resmed 10 pressure at 16/14 cm. Then I began to lose weight, a lot of weight, and in the middle of it I had a titration test that suggested setting the pressure of 7 cm, obviously way down from 16. After all the weight loss (127 lbs) my average AHI was .9 and I started wondering if I needed the therapy at all - I know it happens after big weight loss, even for one study subject, but not too often (my, now old doctor, claims it never happens). I set the machine to 4cm (and pissed off my doctor), and there was no change in AHI.
I'm waiting for a new PSG confirmation, one way or another, that's still 2 1/2 months off. Given .9 AHI average at 4 cm (some days of 0) is it possible that I could shoot up to 5 ahi with 3 to 2 to 1 to 0 cm? How likely do you folks think it is that I still have OSA (I have also been diagnosed with Type 2 Narcolepsy which is not great)?
I look forward a professional (and non-professional) opinion.
Thank you very much my fellow sleep victims.
-Tim
Yeah I know that part. I was the one who requested the test. That's how I felt too - that the odds are on my side.
Do you normally see AHI rise slowly or vertically when the pressure is lowered, or is that another case by case thing with no general rules too? The slower it happens is obviously my best chance.
My thoughts based on very ad hoc observations is that it seems to be non linear when going in the other direction. OA does not tend to decrease until you hit a critical point when the airway opens reliably with the pressure and then it goes down quite quickly. That is kind of the basis for a titration test when you get diagnosed with apnea. They look for that switchover point and set the pressure a bit above that.
You might get a better indication of how things are trending by using a min of 4 and max of 7 and then look at the results using OSCAR. It would be an encouraging sign if the pressure pins at 4 cm and reliably stays there overnight, with no hypopnea, OA, CA, or flow limitations.
Interesting. Are you saying that even though I already know there is an average AHI of .9 at both levels, and I hit 3 AHI just a couple of times in a year, and since those readings are averages (I'm just talking about bare bones My Air reports) there could be discrete points in time that can cause the pressure to go above 4? I'm just really starting to learn here.
Thank you very much for taking the time.
-Tim
OSCAR lets you see all of the events by type and exactly when they occur during the night, and at what pressure. If you have the machine in AutoSet with some room for it to increase pressure above 4 cm, then you will see if there is any attempts to increase pressure and for what reason. I think this will you some idea as to how close you are to having zero events.
If you have a SD card in your machine, all the detailed data should be there, so you can go as far back as you want to look at individual nights.