Can ER doctors give dialysis orders?

I am so confused on this issue. I've been called in the middle of uckthe night only to find the er dr wrote an order for a pt to be dialysed and discharged. lucky for me i read the progress notes and it said the nephrologist was aware but i didnt see a consult on the pt. I called the nephrologist in the middle of the night (luckily i knew he was a nice one) and he gave me orders. So i dialyzed the pt. Other nurses h ave been in my situation and have fought with the staff saying it can wait till morning and that the nephrologist need to give clear orders and that the er dr cannot write dialysis order..only a nephrologist can. i know that is true but is what the hospital doing right? I'm so confused on this issue. The pts potassium was a bit high and thats why i proceeded to go ahead and call the dr. in the other cases of my coworkers..they have been called in the middle of the night for a fairly normal potassium of 5.3 (which is normal for a chronic kidney failure pt).