new to autoset

[thegrons]

When my s9 comes in will I be able to set a min level aside from upper level and if I am at 8.2 on s8 elite and having 18 episodes what pressure setting should I tweak on auto? Upper or lower?

[Pugsy]

The minimum pressure is going to be your most critical setting. Set it optimally to start with and the machine won't have wild ranges in pressure which might disturb sleep or offer sub optimal therapy.

Your S8 uses a different algorithm than the S9 does.
My suggestion to start with if you want to use APAP mode is do something very simple that mimics what you have been using and then evaluate your reports and go from there.
If you have been using cpap pressure at 8.2...then how about using 1 cm below 8.2 and 1 cm above so that it won't feel so different to you.
Your body has been using straight cpap for a long time...it may find that apap with a lot of variation is something that it doesn't know what to expect of it and it might disturb sleep.
Start out modestly and then see where things might need to go.

In cpap mode...you get one pressure setting available...just like with your S8.
In apap mode you have 2 pressure settings available...a minimum pressure where the machine never goes below and a maximum where it won't go above.

[thegrons]

Is the 1cm equal to 8.0 8.3 or 7.2 9.2? I noticed last night I slept very shallow; with the bipap will the machine detect this and increase the pressure?

[jdm2857]

Pugsy is suggesting a range of 7.2 to 9.2.

[thegrons]

Great does lower end number used for when I am breathing fine and the higher end for when machine detects me not breathing so it gives my lungs a boost or wake up call to start breathing?

[jdm2857]

The machine will start out at the minimum pressure setting (7.2). It will stay there as long
as your apnea is well controlled. If it senses that you are having apneas, it will begin to
increase the pressure until the apneas are controlled. It will not increase the pressure
above the maximum setting (9.2).

CPAP machines do not issue "wake-up calls" to start breathing. They pressurize your
airway to prevent the airway from collapsing, as one cannot breathe through
a collapsed airway. The pressure holds the airway open the same way that
air pressure holds a balloon open.

[Pugsy]

Great does lower end number used for when I am breathing fine and the higher end for when machine detects me not breathing so it gives my lungs a boost or wake up call to start breathing?

Nope, doesn't work like that or respond that quickly and that is why the minimum is more important.
The only machines that give a "boost" like you are thinking about are the machines that are designed to treat central apnea issues..those would be the ASV type of machines which yours is not and you don't need or you wouldn't have been given the S8 Elite II.

Here's an example of when apap maximum is useful..I will use myself since I have documentation.
My OSA is worse in REM sleep...sometimes in REM sleep I need more pressure than I do in non REM sleep. Using auto adjusting pressure machine enables me to sleep most of the night at lower pressures and let the machine increase as needed during REM. Otherwise I would have to use much higher pressures all night just to prevent the extra hard to deal with sometimes events during REM sleep.
So I can use 10 to 12 minimum pressure for most of the night and let the machine go higher if it thinks it needs to. Pressure changes don't bother me. Sometimes I have seen over 19 cm be needed...but only for maybe 20 minutes. I sure would hate to have to use 19 all night...