An IV on a dehydrated baby? I have seen a whole ER department fail to get a blood draw from a plump hydrated infant. It seems to be really tricky when you are dealing with kids, and the only thing that makes a difference is practice, practice, practice. The people who are best seem to be those in paediatric hospitals that do these procedures a dozen times a day, every day. You were right to go to the ER - had they promptly and successfully helped the baby you wouldn't have thought twice about your decision.