Yesterday, I had my second sleep test.  The doctor has "prescribed" a BPAP machine for me.  I had not heard of a BPAP before this, but have read what little I could find about this type machine.  However, I would like to hear from you.  I have a basic understand of what a BPAP does, but beyond that, not much.  Why would I need it?  What has been your experience if you've used? Does a certain mask work better with a BPAP.  Anything you can think of about BPAP.
Thanks!

A "BiPAP" (Respironics branded term) or "bi-level" (generic term) is a CPAP machine with separate pressures for inhalation and exhalation.  

Most CPAPs have some type of "exhalation relief" (called EPR in Resmeds and <something>-Flex in Respironics, for example).  These are very mild reductions in therapy pressure issued only during exhale.

If full-on constant pressure is not well tolerated (e.g. you cannot exhale easily against your therapy pressure, or have lung conditions such as COPD or asthma) then the exhalation relief settings are tried on the CPAP first.  If that still not does provide relief then a Bi-Level is tried.  The inhale pressure will be set to your therapy pressure while your exhale pressure will be lowered however far it needs to go to provide relief.  In addition many Bi-Levels have a timed breathing circuit which can help you 'synchronize' your breathing with it, again making it easier for some people to breathe.  (Then there are some people, like me, who do not breathe very regularly even when asleep and end up fighting the bi-level, trying to inhale when it wants me to exhale and vice versa.  Everyone is different!).

Also, was "BPAP" written down?  If not, is it possible what was said to you, was "VPAP" instead of "BPAP"?  A 'regular' or 'plain' VPAP is Resmed's branded term for a bi-level.  But there are other flavors of VPAP such as the Adapt SV which are way beyond CPAP/bi-level therapy in both features and complexity.  These are expensive, special-needs machines.

Hope that helps, Blessings,
--pseudonym

P.S.  Have a look at the Sticky Posts at the top of the forums, especially the machine and mask multi-media center, you'll get an idea of some of the different equipment that is available.