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PoolQ wrote:EPR is also an average over 5 breathes and pressure support in a Bilevel machine is on a breathe by breathe basis

no, no it's not.

epr is fixed.

pressure support on a respironics bilevel can vary over time, resmed machines use a fixed pressure support.

only ASV machines vary pressure support breath by breath.

perhaps I am confusing settings and implementation.
since EPR tracks inhale pressure with a fixed offset, the exhale pressure will track whatever the inhale pressure is doing. According to:

http://www.resmed.com/us/en/consumer/sup...toset.html

"AutoSet devices assess breathing adjust pressure according to a five-breath average"

so an EPR setting of 3 is of course static at 3, EPR is not an absolute pressure setting, it is a delta pressure from inhale pressure. The pressure you see when you exhale however is not and will vary, on a 5 breathe moving average, based on what the CPAP machine is doing with inhale pressure.

At least on my BiLevel machine I set a fixed exhale pressure and a pressure support that when added to the exhale pressure sets the minimum inhale pressure, so my inhale at any given time will be between this min inhale pressure and the set max inhale pressure, but my exhale pressure is fixed regardless of what my inhale is doing.

Increasing IPAP will most likely increase Sp02 because it gives the patient more air, increases the pressure support level, and results in a higher tidal volume achieved. Gas exchange becomes more efficient.