I am a new member to this site and am having some problems with my sleep apnea that I'm really hoping someone could provide some insight into.  I was diagnosed with sleep apnea about 4 years ago and at that time I was like 300 lbs. overweight.  After about 6 months of attempting to get a decent night's sleep using my auto bipap machine, I gave it up and stopped using it.  About a year or so ago after I had already began to lose the weight, I developed a case of atrial fibrillation which was corrected via cardioversion, but ever since then, I haven't gone a night without using my machine.  My issue now is this...I've lost all of the weight (and happy to say without any surgery or medications), but the abdominal discomfort that is being cause by the auto bipap has increased to such a degree that I wake up in the middle of the night in borderline pain because there's so much air being pushed into the lower areas.  This generally lasts for hours and happens probably about 1/3 nights.  The other nights it still occurs but it's not to that extreme.  I have had my sleep doctor's office continually turn down the settings on it  to correct the situation, but now they say the settings are as low as they can go yet I am still having the problem.  This leads me to wonder...Do I in fact still have the sleep apnea at all?  My pcp had told me that it would be entirely possible for me to not have it anymore after losing the weight.  When I read these forums it sounds like once you've used it for awhile, it's dangerous to stop, and I don't want to have heart rythem issues again.  I decided to get a new sleep lab done to check and see, but the script I received was for a retritation study.  Isn't that for someone that's already using a cpap or bipap, and not to see if the disorder still exists?  Am I now just going to be stuck using the machine regardless because I used it for a year already?  I'm not sure really what I should do at this point.  I suppose if it was truely necessary to use the machine every night for the rest of my life I could accept it, but I don't see how I can tolerate the abdominal discomfort much longer, and no one seems to have an answer to the problem up to this point.  Is a retitration study the way to go here?