Well, after nearly 6 hours in the ED today, Avery is a new person. I say the ED because that's where we physically were, but our pediatrician called in ahead and had us fast-tracked in. Please don't let that fool you though, as it did he and I -- we were still there all day!
Her bloodwork came back and showed that her CO2 was quite low (low enough to where Kyle said that had a certain kind of alkalosis not "masked" the real number (without going into too many medical details

) she probably would have been shipped to base and admitted, so I'm glad we went in today. It wasn't medically urgent so we all went back and forth on the decision, but it definitely made a huge difference in getting Avery "over the hump", so to speak.
She ended up getting a bolus of 150ml fluid and some Zofran to start. Even after just that she was acting much better and taking juice & pedialyte like the starving child she should have been! She was still somewhat dry though, and the (fabulous) doctor that was taking care of her said that if she's here and has an IV in her little hand, we're going to really tank her up before she goes home. So she got another 150mL, plus 60 more of fluid with dextrose (sugar) in it to help correct her low blood sugar. At this point she was a drooly mess, crying real tears and started to get puffy from the fluid

She was acting 10x better than the morning, so they just rechecked her glucose (normal) and sent us on our way!
Keeping up with the intake should be easier now that a) she's had fluids and is out of the vicious cycle she was in (dehydration -> crappy feeling -> decreased appetite -> dehydration), and b) we have more Zofran available if we need it. Man, I love that stuff (speaking from experience, as you all know quite well!). Earlier, she would get 1/2 an ounce in her and immediately vomit. As long as that isn't an issue anymore, Kyle and I should be capable of pushing fluids enough to keep her hydrated. Let's hope, anyway.
While we were there, we also discovered she has croup. She got steroids and now of course we'll be watching Elise to see if their coughs aren't "back", but "new". It's likely, considering how communicable croup is, but whatever. We'll wait and see, but I imagine they've shared it. I wouldn't mind that at all, honestly, because it's easily treatable. Between that and the boost we received in getting Avery over this GI bug, we'll be on our way to a healthy household.
Of course, that is until Elise picks up this GI thing in full swing, but at least she's my good eater. We'll pray that if she gets it, she can at least keep herself going without as much (costly and time-consuming) intervention!