We finally got to see the GI docs today and they gave us a possible answer. There are a laundry list of things that can cause someone to vomit but since they have essentially ruled out anything structural they are going with it being something functional. Their top thought right now is a serious bug (I can't remember the clinical word for it) but it causes inflammation in the stomach. This inflammation can cause a temporary intolerance of regular food or formula. When Drew is having Pedialyte he is not throwing it up. When we give him formula it comes shooting back out at us. The whole sitting up thing can just cause some extra pressure on an already inflamed stomach and just be the trigger to the vomit. ANYWAY, the GI specialist wants to try a different formula. Coincidentally, the formula they want to switch him to is something we've already been on. Its a predigested formula called Elecare that should basically give his stomach a break until the inflammation goes away, a week or two they estimate, 4-5 at the most. At that point we should be able to switch him back to his regular formula and go on doing our thing.
The doctor seemed reasonably confident that this was the most likely cause of the vomiting. He gave us some other possibilities and options for tests that we would do if the formula thing doesn't work. They are keeping him for the weekend because they expect it to take 24-48 hours on the new formula for the vomiting to stop. If by Sunday he can tolerate the predigested formula and isn't vomiting or dehydrated then we will get to come home on Monday. If not, the tests will continue until we get to the bottom of this.
This, like all of the other strange problems that Drew has had, is not a CF problem. CF kids do tend to suffer from all sorts of GI complications in addition to lung problems which is why they admitted us to the CF floor and did all of the normal tests to rule out any of the typical CF digestive issues. But this isn't related to the CF whatsoever. This isn't the first doctor who has referred to Drew as unlucky. Hopefully the little guy will get over this and have a healthy stretch for, oh, the next 30 years (though I don't want to limit it to 30! :)