settings questions on an aircurve auto

[wrlc56]

this isnt my first aircurve auto but  i've never messed with the settings except to turn the ramp off. on my new one i would've thought it'd been set to auto but i noticed this is set on S. i've been trying to learn more about which is best, S or auto. ive known about ipap and epap but i didn't know until now what the PS # was all about.
i haven't had a sleep study since 2008 and haven't really had issues but have wondered since i weigh considerably more than i did almost 14 years ago if i'm  still getting what i should. i have mobility issues so getting another study would be a problem. as such i haven't asked for one. my insurance asked for my 2nd sleep study in 2008 but hasn't since.  my 2008 #s were 15/11.  if i use the S mode do i have to raise both the ipap and epap  the same amount to keep the same ps#?  auto preset #s are  25/4.  if i use auto do i need to change anything. if i do change the default auto #s  do i have to keep the PS #, the difference between i and epap the same?
can  i try  bumping up my PS  to 6 so instead of my 15/11 try a 17/11 or 18/12? 


thanks for any advice

[staceyburke]

I can't advise anything with out data, OSCAR is what is used here.  It is totally free at the top of the site.

But I can explain a little about bipap (the type of machine you have)


Pure CPAP delivers a single constant pressure.  This pressure is what splints open the airway.  APAP (AutoSet) is what we prefer to see as it can vary the pressure to suit the situation.  For now, let's forget about APAP.

Basic BiLevel delivers two fixed independent pressures, EPAP is Exhale Pressure and is what actually splints the Airway open, It is the equivalent of "Pressure" in a CPAP and does the same thing.  
IPAP or Inhale pressure is the higher of the two pressures.  Once the Obstructive Apneas are resolved with the Exhale pressure (EPAP), IPAP is used to resolve hypopneas, flow limits, RERAs, and UARS.
The difference in these pressures is called Pressure Support or PS.  PS is always added to EPAP by convention to get IPAP so IPAP = EPAP + PS
FYI if you were to set the EPAP = IPAP you would have a basic pure CPAP functionally.
The above info is derived from Titration guides.

[Crimson Nape]

The S mode is a static bi-level setting. You would set your EPAP and IPAP pressures, with the difference between the two being considered as the PS (Pressure Support). In the VAuto mode, you would set your lowest EPAP pressure, usually 7 cm for an adult, your maximum IPAP pressure and the PS value. Using the previous settings would start off at your EPAP pressure, adding the PS setting for the IPAP value. This will allow a pressure range up to the maximum IPAP pressure setting. Using your example of the default pressure of 4 cm for EPAP, 25 for the maximum IPAP and a PS of 6, would give you a pressure range of 4/10 (EPAP/IPAP pressures) all the way up to 19/25. This range is rather excessive and can cause arousals and air bloating. Your best bet is to download OSCAR, get an SD card (2 to 32 GB in size) and capture your sleep data for analysis.

[wrlc56]

ok i understand now. S mode is what each of  my older bipaps had. i should have known that i guess. i seriously doubt i would use the oscar stuff. i might tweak it a little at a time and see how that goes.  i appreciate the help

[Crimson Nape]

I have to ask, how do you know what to tweak, and by how much, if you don't analyze your sleep data?