Actually, I do know of CRNA schools that except ER nursing as long as that ER is in a level 1 trauma center. I am a ER nurse and a critical care nurse, however, I do not work in the ICU and do not want to or thats where I'd be. I have taken care of patients with balloon pumps, LVADS, etc. I do not believe, I could just go to the ICU and take on a fresh heart. I also do not believe that just any ICU nurse could do it either. I highly doubt that the ICU nurses would be able to take care of half the heart babies etc, that we see either.
I believe that every facility is different. I worked in one facility that if a patient had in a chest tube they were automatically in the ICU. In the facility I work in now, there are patients with chest tubes hanging them off their IV poles and ambulating in the hall.
About the comment about the patient being too unstable to be in the ER. Thats pretty funny. However, I will say this: ER docs are just that. An ER doc is not an ICU doc the same as an ER nurse is not an ICU nurse. So, yes we have had docs wanting to get a patient upstairs ASAP because of their condition. We do have parameters however, before we can send a patient upstairs. Systolic BP must be above 70 for instance. We cannot, and will not transfer a patient that is too unstable for transport.
It may be nice to have a doc in the ER however, they are not the ones running between all 30 beds in my ED. It is the nurses. I have had 4 and 5 vented/critical patients at the same time, and oddly enough when we are boarding this many ICU patients in the ED, there is a bad accident and the traumas start comming in. That ER doc is with those traumas. He could care less about the other "hold ICU" patients. They are no longer under his service. I am the one hanging/titrating gtts until I have a bed ready. I once asked an ED doc to write me an order for propofol for a vented patient and was looked at like I had 3 heads. Our patients have A-lines, we monitor end tidal CO2 etc. Am I a critical care nurse Yes! ICU nurse however NO!