IPAP / EPAP Confusion !!!!!

I have learned quite a lot from this forum about Sleep Apnea. One area that I’m still a little confused on is the purpose of the IPAP & EPAP pressures. I know that IPAP is the (Inhalation pressure) and the EPAP is the (Exaltation pressure). Which one (IPAP or EPAP) is responsible for preventing the Apnea?

If the EPAP prevents the Apnea, then what is the purpose of the IPAP pressure and vice versa?

I have read some places that the EPAP pressure prevents the Apnea, and other places that the IPAP prevents the Apnea.

My IPAP is 9 and my EPAP is 5.

Thanks!

Very simple reason. Two pressures generally feel much better & allow for some flexibility over a single pressure machine.

A straight Cpap and an Auto will run constantly at the one pressure. Some brands have extra features called exhale relief (C-Flex for example). These are features added to try to ease the burden of a single in-hale / ex-hale pressure.

Bilevels go much further. By creating a gap between exhale & inhale & switching as the sleeper breathes, the feeling is so much more comfortable and many people prone to aerophagia (air in stomach) can get relief with bilevels that they can't get from single pressure machines.

The Epap pressure is set to the level needed to eliminate serious apneas especially the no-airflow ones (outright airway blocks). The Ipap pressure is typically set 3 CMs above Epap and that extra pressure is intended to take care of flow-limitations and hypopneas.

In summary, the advantage of a bilevel is that 2 pressures seem to solve more problems for OSA sufferers than you might get from a single pressure machine. But part of this also has to do with what pressures are needed for the sleeper.

DSM

Print out a Encore "Daily" report, at the bottom it will show you the table data and what each pressure addresses,

IPAP=FL, Hypopnea & VS
EPAP=Apnea and VS

EPAP is the big hammer it takes care of the most severe events, you adjust EPAP up until AI=1 or less, then increase IPAP to eliminate the residual Hypopnea, FL.

You always want to eliminate the AI or Apnea first with EPAP then adjust IPAP up to reduce residual HI.

EPAP is the big hammer,
IPAP is the little hammer,

In Auto mode machine should find these automatically "IF" your range between IPAP Max and EPAP Min is wide enough to allow it to work.

If my settings were unknown and I used a CPAP prior, I would set EPAP down lower than CPAP as the Minimum and IPAP much higher + any PS Support Max setting. PS support on the Minimum side is hard coded so you cannot change that.

You can usually handle higher swings of IPAP more so than you can with EPAP.