biflex and rise time - what's the difference?

I'm having a hard time finding anything explaining a real difference between rise time and biflex. I can't find a good explaination of the differences, and the descriptions on them individually make them sound the same. I assume there's a difference, though, since the same machine will have settings for both rise time and biflex.

No comparison, biflex is a comfort setting that softens the pressure changes so they don't feel so sharp.

Rise time is used to in manual mode to match your normal breathing pattern, it is the time it takes to go from end of exhale to peak of inhale. if you match that timer correctly to your breathing it should transition from exhale to inhale smoothly, machine needs to match you as opposed to you matching it.

I would get my rise time set first to where it is comfortable then apply biflex if wanted.

http://biflex.respironics.com/

As Snoredog said, rise time adjusts the speed that the pressure rises when transitioning from epap to ipap.

But risetime fiddling can be problematic. We had an example here recently where someone set their ristetime on a bipap to 5 (settings are from 1 to 6).

The 5 he set it to meant it was taking 500 millisecs to rise. The user was saying how his AI was around 5.0 each night.

I suggested he change rise time to 3 (300 milisecs) and his AI dropped to around 2.0

The problem with setting risetime too long is that it reduces the volume of air breathed in a given cycle as it feeds the air more slowly at the higher risetime settings. That may feel nice but can lead to reduced therapy.

It is a juggling act between comfort with the machine vs achieved results.

Good luck

DSM