Question:

Hi all, what is the difference between bi-level and bi-flex? I just read something about this but need some clarification.
Thanks, DMW

a bi-level machine is like a straight cpap machine but has 2 separate pressures for inhale and exhale instead of a single pressure found on cpap.

For example if you were titrated at 15cm on cpap. With a bi-pap you could have 15cm inhale pressure and 11cm exhale pressure, a 4cm span. Cflex and EPR generally have only a max. 3cm difference.

Bi-flex is a feature like Cflex which drops the pressure on exhale automatically, it is based upon your breathing pattern. In fact, the Cflex feature found on cpap machines was derived from the Bi-Flex feature on Bi-Level machines.

Bi-Flex = relief feature found on Respironics Bi-level machines.
C-Flex = relief feature found on Respironics CPAP machines.
EPR = relief feature found on Resmed machines, does not work in auto modes.

Respironics invented and owns the Patent to Bi-flex and C-flex features.

Bi-pap Auto: Same as a cpap autopap machine but it also has 2 separate pressures for inhale and exhale in addition to other settings for rise times etc..

Bi-paps are generally used at higher titration pressures to offer more relief on exhale than a cpap machine can offer with features like Cflex or EPR. Bi-paps also can go to much higher pressures such as 4-25cm, 4-30cm or higher (vs. 4cm to 20cm on most xpaps).

Bi-level is a type of machine. You set one pressure (higher) for inhaling (the "IPAP" pressure) and a separate pressure (lower) for exhaling (the "EPAP" pressure.

Bi-Flex is not a type of machine. Bi-Flex is a comfort feature found in Respironics BiPAP (bi-level) machines.

Bi-Flex slightly reduces the beginning of the already lower "EPAP" pressure when you first begin to exhale each time. During the remainder of the exhalation, the regular EPAP pressure comes back in.

In other words, "Bi-Flex" in a Respironics bi-level machine acts much the same way "C-Flex" does in other types of Respironics machines. C-Flex is a comfort feature available in many of their straight cpaps and autopaps.

Either one, Bi-Flex or C-Flex, simply drops the start of each exhalation somewhat. Makes breathing out feel more comfortable for many people. Both Bi-Flex and C-Flex can be adjusted to "1, 2, or 3". A setting of "3" for Bi-Flex or C-Flex gives the most drop in pressure at the start of the exhalation. The "1, 2, 3" settings do not mean the pressure will drop that many cm's. The amount of drop Bi-Flex and C-Flex give to the start of an exhalation depends almost entirely on how forcefully a person breathes out. Both can be turned off if a person prefers not to use them.

Bi-Flex and C-Flex can be turned on only through the "setup" menu on a machine that has it. So, if the homecare provider did not turn that comfort feature on when they set up the machine that has one or the other bult into it, it won't be available.

"Bipap" is often used as a generic word referring to any manufacturers' bi-level machine, even though BiPAP is Respironics' trademark name for their bi-level machine. BiPAP with Bi-Flex is their bi-level machine with their "Bi-Flex" comfort feature in it.

My edit: oops...was typing and didn't see snoredog's response. He described it well!