Not much to add here. I hope by now you've gotten her back to the hospital and they've given her some IV fluids. Not to "feed" her, but to rehydrate. An average person needs between 2.5 and 3 liters of water a day just to keep up with normal body processes and insensible water loss through the skin and lungs (more if you're sweating, exercising, febrile, etc.) While adults don't get dehydrated as easily as little babies do, it can happen, especially if she's like most people, who barely drink enough water as it is.

Juices and sodas have less water per volume than a plain glass of water, and caffeine- or alcohol-containing beverages can cause you to lose more water than you've taken in. Most people are lucky there's water in food, otherwise a lot more of us would be dehydrated! (Weight loss tip: drink a big glass of water before every meal. Many people eat because they're thirsty.)

All that aside, Sorch, I hope you're reading this after bringing your daughter back from the hospital and that she's feeling better after she's "tanked up" with a couple of liters of IV fluids. There are lots of reasons for post-op nausea, and that's outside my area of expertise. If this ever happens again--or if it happens to someone else--and the standard stuff doesn't seem to be working, it might help to call the anesthesiologist who's on call at the hospital. They have lots of ways to deal with it. But as has been mentioned already, hydration is important.

Aloha,
Mark