Hi SleepyTime and
(02-14-2013 08:10 PM)SleepyTime Wrote: First let me thank you for making available the software and PDF files with information I couldn't find anywhere else.
Having used a Medicare issued CPAP for about 3 years, I finally shelled out $999 for the S9 with H5i to get the air required and not a steady stream at 10cmH2O as prescribed with the CPAP.
Here's what I don't get. When I bought the S9, the tech at the store set it Low 5 and High 14. As I look at the pressure line, it starts at about 5 then climbs within 30 minutes or so to about 14 and stays there until I wake up...often 4 to 5 times a night. Each time when I go back to sleep, the same pressure climb.
To see whether the pressure was "stuck" I increased it several times over a few nights up to 16 cmH2O. Each time the pressure would climb to the max set point and remain there unless I had a big leak from my MirageFX full face mask.
I though the pressure would vary with my demand?
Could the S9 sensors be defective. Electronics do fail as we all know.
Any similar experience?
Btw thanks to the software I now know I have obstructive, central sleep apnea and hypopnea often in one night. Sometimes just hypopneas.
Only the pressure stays at the max!
What is your AHI? Are events spread out fairly evenly? Does the pressure start raising as soon as you turn the machine on (discounting ramp, of course), or after you've fallen asleep? When was your last sleep study? Was it an in-lab study?
The reason I ask is because you say you've used CPAP for about three years. I'm assuming that means that your sleep lab titration was 3 years (or more) ago. A lot can change in 3 years and, unfortunately, OSA can get worse with age. Also; I believe, and this is just my opinion, that in-lab titrations often lead to less than optimal pressure, as the discomfort of the environment can lead to a lighter sleep and less relaxation.
If the AutoSet doesn't start raising pressure until you are asleep (not counting the ramp) and your AHI is high (above 5) and the apneas and/or hypopneas are spread out; then the AutoSet might be doing the best job it can within the limits it has been given. Your pressure needs may be greater than what has been estimated.
Have you considered setting the top end at 20cmH2O and seeing what happens? If the machine is not malfunctioning it will not go any higher than what is needed.
Before doing this though, I would shut the ramp off and wear the mask with the machine on while awake for a little while to make sure the pressure doesn't raise when you know it isn't getting any signs of apnea/hypopnea or snore. If it raises pressure while you are awake and not snoring, etc., then the machine is probably defective and should be replaced - it should still be under warranty.