Switched from CPAP to APAP

I switched from a CPAP to an APAP a couple of weeks ago and have questions...

My AHI jumped up a bit so that it is now over 5 rather than under. It was up around 9 at first. It does seem to be coming down over time, although I look to be settling in around 6 or 7. With the CPAP it was at 5 or less on average, usually in the 2-3 range. Also, my CPAP always reported 0% for Periodic Breathing but I'm now seeing 1-2% per night. Historically I will wake several times to urinate if I am not using a CPAP and at least once if it isn't being completely effective (e.g., because of medication). I'm sleeping through the night with the APAP, so I have a good indicator things are fine. My Fitbit One isn't showing any increase in restlessness during the night, a perhaps irrelevant detail but might as well put it out there. I don't recall my current 90% number. Like AHI it started out higher on the APAP than it was on the CPAP, but has been coming down. Oh, and I live at 7300'.

Ok, the first question is should I even be paying attention to the numbers at this point or should I wait a few more weeks for my body to get used to the APAP?

I've read that Period Breathing of 1-2% is nothing to worry about, that events are common when falling asleep in healthy people, and that its also quite common at high altitude. Just looking for confirmation that this is others' understanding as well.

I am curious about why the CPAP reported 0% Periodic Breathing while the APAP is reporting a non-zero number. One clear difference is that the CPAP was providing a constant "high" pressure (C-Flex+ notwithstanding) while the APAP doesn't, but since Periodic Breathing is a central event I wouldn't think that mattered. Note I did not use Ramp with the CPAP. Any thoughts on this one?

Would changing the minimum pressure on the APAP influence any of this? I'm currently set for the full 4-20 range, but have been thinking I might be better off bumping the minimum up to 6 and seeing what happens.

My current plan is to wait another few weeks, see what the numbers are, and then if needed try bumping the minimum up to see what impact that has. Of course I'm quite open to suggestions for a different course of action.

haroldb wrote:Would changing the minimum pressure on the APAP influence any of this? I'm currently set for the full 4-20 range, but have been thinking I might be better off bumping the minimum up to 6 and seeing what happens.

Most definitely the minimum pressure could affect pretty much everything you mentioned.
If it isn't set optimally the machine can't respond in a timely manner and all sorts of stuff can happen....higher AHI and even some of that PB.

Without seeing the detailed reports...yes, increasing the minimum is most likely the way to go as long as the AHI isn't predominately central in nature.

Would changing the minimum pressure on the APAP influence any of this? I'm currently set for the full 4-20 range, but have been thinking I might be better off bumping the minimum up to 6 and seeing what happens.

It should not be left wide open like this. It takes time for it to reach effective pressure. Look at your 95% pressure and set the minimum to 2 cm below that for a few days.

I don't hold to the 90 % pressure thing and 2 cm below until I see a consistent pattern long term (like 2 or 3 months).
The 90/95% pressure numbers are easily skewed by things.
See this.
viewtopic.php?f=1&t=39869&st=0&sk=t&sd=a

Get the minimum optimal and often the maximum and 90/95% number gets lowered significantly and will stay lowered most of the time.

When I had my CPCP 6 years ago the pressure was set at 10, it had been that way for 10 years before I got an APAP. The APAP showed me
my 90% pressure ran around 12.5 and higher so I set my range from 10 to 20. The doctor prescribed 8 to 20 but I wasn't
getting enough air and since I had already been use to 10 to start with that seemed like a good bottom pressure. I change the range
and thank goodness the DME left me the manual.
My AHI is typically 1 or below. By making the lower number closer to my average 90 % pressure when I start to have
an event my machine reacts faster because it doesn't have to climb so far. At least that's how I see it.

Bryan

Thanks for the advice so far!

Since I don't see a downside. I'm going to go ahead and bump up the minimum pressure starting tonight to see what happens.

Harold, what was your CPAP pressure? I'd think having a range just under that but with a little more room above the old CPAP pressure would be a place to start.

haroldb

You say that the APAP is wide open: Min pressure = 4, max pressure = 20.

What was your CPAP pressure set to when you were using CPAP?

Chances are if you set the min pressure only a cm or two below what your were using when you were using CPAP mode, then your AHI on the APAP will probably go back to where it was when you were on CPAP.

I believe it was set at 11 (I've lost weight, so it has come down from the original prescription). My current 90% number is 10. I'm going to set the minimum at 8 tonight and see how that goes.

Harold,

That sounds like an excellent idea. Let us know how it goes. As it turns out, that lower number is the single most important number when it comes to APAP. In most cases, the upper number can be just about anything as long as it is higher than what you need for a max pressure. Keeping it at 20 is probably OK. Note that when you make changes, it takes a few days for your body to adjust to the new settings. Your body adapts to the pressure. For example, I needed to do a study recently to see how I breathe without CPAP, and they asked me to go without it for several nights so I would un-adapt to having the pressure. I was surprised at how long it took.

-john-

Well, immediate drop of 90% CM to 9 for the couple of days I've tried the new minimum. No change in periodic breathing.

After giving this some time, if I stay at 9cm for a while should I back the minimum down to 7cm and see what happens?

How about an image of last night's detailed report?
Don't know how? viewtopic.php?f=1&t=81072&p=737779#p737779
Just how much PB are we talking about here and does it have many Clear Airway events in it?

1-2% Periodic Breathing

I have to go pick up a USB memory card reader since the machine I installed Sleepyhead on doesn't have one. Given my schedule this week it probably won't until next weekend.

Okay....how about the PB....do you see many clear airway events getting flagged during the PB flagged time?

How would I see that without being able to look at the SD card?