odd change in pressures ... ?

[Dreamless]

I was looking at the past week sleep data in Sleepyhead, I'm still dialing in PS to try to minimize the hypopneas. While looking at that data, I came across something I hadn't seen previously and I've been using Sleepyhead for at least 2 years.  The pressures dropped shortly after 5 am.  ??  Why would this happen ?   I will post an image here for you folks to take a gander at and see what you make of it.  I'm using a System One bipap with Auto SV.  

Current settings are:  Max: 25
                               Min. EPAP:  9.5
                               Max EPAP: 15
                               PS: 6 - 15
                               Auto Rate
Thanks, 
Dreamless

[Sleeprider]

Never seen it before and haven't got a clue, but note a hypopnea indicated very close to the pressure drop, and it shows up in the Statistics. That's a busy machine in terms of backup breaths. What was it like before you increased PS min to 6.0? You have a very low event rate and hopefully you're feeling good.

[Dreamless]

Sleeprider,

I was diagnosed with Central apnea.  I was having quite a few hypopneas and still have the bad night with them here and there. Sleepyhead also flags periodic breathing just about every night.  I had seen Flow Limitations (I still don't really understand those) on most every chart until I bumped the PS to 6.0. We, the wife and I, started trying to get my pressures where I have the least events and I think we're getting pretty close.  The PS was 3.0 - 15.  So while the AHI is really good these days, I have an issue with waking up at 4 am almost every night.

Dreamless