question about maintenance fluids and drips

If a patient has an admitting order for maintenance fluids (say, NS @ 125 ml/hr, or whatever), is this order assumed to be in place until the MD changes or discontinues the order? How do you document when you hang a new bag? One of my coworkers told me that she gets a new order for every bag of fluid she hangs, even if it's the same fluid and rate -- her rationale being: since it's the ER, we don't routinely document I&Os, and that's the best way to be able to see how much fluid the patient has gotten. Another coworker told me he just checks off the same order in the EMR whenever he hangs a new bag -- which still would show the total number of bags hung, if someone scrolled back to count the number of check offs.

Similarly, how do you document when you mix up a new bag for a drip? Do you check off the same order, get the docs to put a new order, or have some other way of documenting that the drip has not changed? I hadn't actually thought about this until today, when I called report on a patient being admitted and the floor nurse asked me what she should do when the nexium drip ran out. I told her to simply mix a new one, but then realized I didn't know the actual policy. Meant to ask my supervisor, but it turned into a crazy night, and now I find myself reading the forums trying to wind down.