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Respironics 460 Auto-Trial mode
#11
(07-28-2015, 11:02 AM)Sleeprider Wrote: The auto-trial should not skew results as your AHI is known based on 25 days of fixed CPAP. My suggestion for trial mode would be a minimum pressure of 10. Max pressure should not be too important as the algorithm will only go as high as necessary to address flow limitations, snores and other event triggers. You could set it at 20, or more conservatively at 15. The auto-mode could easily place you right back at a fixed pressure of 12, but the greater range would make for a better case for APAP if you want to demonstrate that lower pressure is adequate most of the night, but the machine adjusts upward as needed for certain events.

I set it to a minimum of 10 and a maximum of 15. SleepyHead shows that it spent a lot of time at 10 and only spiked to near 15 a few times. The 95% rate was 13.5 and the AHI was 2.87 (it was 1.83 the night before on straight CPAP).

[Image: JeFc9rN.png]

[Image: yjD1lXe.png]

I pulled the mask off a little before 3 and put it back on at 4 so ignore that section.

I was thinking that maybe the minimum pressure should be a little lower?

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#12
CPAP pressure is typically titrated at your 90% exceedance value, so this result is close to what I'd expect. The pressure peaks of 1.5 cm represent slow pressure changes to evaluate higher pressure. This is typical of the PRS1 Auto algorithm. When no improvement was detected, the pressure drops back. Around 12:15 AM you had a flow limitation or snores, and pressure increased to 12.5, then dropped back to 10 before rising again, mostly to 12-12.4 until 2:45. We don't have the events chart so I can't tell you why pressure increased. The results look very good and, so-far, confirm the CPAP pressure you are using. How did you sleep feel compared to steady pressure? You spent more than half the night at a lower pressure, and averaged out very close to your previous CPAP pressure.
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#13
(07-29-2015, 08:08 AM)Sleeprider Wrote: We don't have the events chart so I can't tell you why pressure increased.

This one?

[Image: 8u9v5uZ.png]
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#14
Now you can see how things line up. The machine responds to VS but not VS2. The first pressure rise is because it detected snore vibrations, so pressure was increased until that went away. It then increased again during a period you did not have snores or flow limitations but had several Hypopnea and OA. It rose again on a FL near the end of that period. Later in the night, the pressure rise was from a couple snores that ended up with a couple OA events.

[Image: 8u9v5uZ.png]
[Image: JeFc9rN.png]

One advantage of CPAP pressure is it is always on and doesn't need precursor events to cause a pressure rise. But your chart shows that, except for the first two events, when you had OA an H events, your machine was at or above your normal CPAP pressure. So the auto-algorithm was working properly, keeping pressure lower when possible, and generally intercepting events before they occurred.
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#15
(07-29-2015, 08:36 AM)Sleeprider Wrote: One advantage of CPAP pressure is it is always on and doesn't need precursor events to cause a pressure rise. But your chart shows that, except for the first two events, when you had OA an H events, your machine was at or above your normal CPAP pressure. So the auto-algorithm was working properly, keeping pressure lower when possible, and generally intercepting events before they occurred.

Ok, that's good then? Dont-know

Should I set the minimum pressure a little lower or is it ok where it is? I realize this is only data from one night but does it seem like I'd benefit from APAP over CPAP?

I'm not sure if I slept better or not, my wife was up a few times during the night and woke me. Plus I tried to sleep on my side and either knocked the mask off or pulled it off altogether at one point. I think I feel less tired today then I had over the last few weeks but it's still early in the day. ;-)
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#16
You are in the right ballpark. There is no harm in a lower minimum, but I certainly would not go below 8.0 or 8.5 as a minimum. What you're looking for is the ability of the machine to raise pressure fast enough to prevent most events, or be at therapeutic pressure when they occur. And yeah, functionally the machine, and you did great in auto mode with no significant change in the good efficacy you get with constant pressure. So the remaining question is comfort.
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#17
I think I'm going down the wrong path... Last night I changed the minimum pressure to be 9 and left the maximum at 15. The last night I was on straight CPAP the AHI was 1.83, the first night with auto-trail was 2.87 and last night was 3.58. I think that I am sleeping better as it seems a little easier to breath but that could be all in my head.

[Image: oPEbmym.png]

I'm going to leave it at the current setting and try one more night like this, then will go back to straight CPAP.

Any comments/suggestions?
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#18
A minimum pressure of 10 certainly avoided the fluctuation you saw last night. That looked pretty good, although there are strong similarities in the pattern. Your AHI peaks around 2:00 AM, and again after 4:00 AM. Those kind of patters look like sleep stage. There is nothing in the actual numbers to be alarmed about, but the trend shows you're a little better at a higher minimum. Be careful about drawing conclusion on one-night of data. The two recent nights are nearly identical in numbers and distribution of events. Your average and 95% pressure appear to be lower in the most recent night, so the "feel" might not be an illusion. That's why it's best to make that call before you look at the data.
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#19
(07-30-2015, 12:58 PM)Sleeprider Wrote: A minimum pressure of 10 certainly avoided the fluctuation you saw last night. That looked pretty good, although there are strong similarities in the pattern. Your AHI peaks around 2:00 AM, and again after 4:00 AM. Those kind of patters look like sleep stage. There is nothing in the actual numbers to be alarmed about, but the trend shows you're a little better at a higher minimum. Be careful about drawing conclusion on one-night of data. The two recent nights are nearly identical in numbers and distribution of events. Your average and 95% pressure appear to be lower in the most recent night, so the "feel" might not be an illusion. That's why it's best to make that call before you look at the data.

Maybe I'll try going the other way with the minimum pressure tonight - changing it to 10.5 or 11 - and see how the data looks tomorrow.

Thanks for your help with this, I appreciate it. Thanks
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#20
Last night I set the minimum pressure to 11 and left the maximum at 15. AHI is still going up, it was 3.94 last night.

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