Selena, I've agonized over this myself.  My husband thinks I over react when out 2 year old salt-waster vomits.  I do wait 1/2 hour and see if he'll take anything by mouth after he has vomitted.  If he is unable to ingest anything, I'll call the Endo and let him know what is going on.  He usually tells me to inject with the solu-cortef and get him to the ER to get his levels checked.  If by the time we get to the ER and he's starting to bounce back, we don't let them do the IV, just the bloodwork and possible a finger stick to check glucose.  I have decided that it's better to go to the ER and find out things are OK than to have things get way out of control at home and put his life in danger.  Possibly when he is older, and talking better, I'll be able to judge the situtation better on this topic.  Stick to your guns and do what YOU think is best!!!