My previous facility also rented out a unit to an LTACH company. My understanding was that there are very strict CMS rules about the degree of separation (not physical separation but functional separation) between Hospitals and LTACH's. Our Nurses could not work in the LTACH unit without a "distinctly separate" hiring and orientation process from the hospital's. We did provide some services to LTACH patients just as we did in Nursing homes in the area such as lab draws.
I would think your hospital would need to be very careful about adequately defining RR evaluations by their staff, and I'm not even sure it's really possible without leaving the RR Nurse and other staff exposed to problems. I would check with your malpractice insurance
provider or union to make sure you are covered when seeing these patients. These are not patients of your hospital and could potentially be seen as patients the hospital staff cannot treat based on CMS separateness rules, which would mean you cannot have a Nurse-patient relationship with them while on the Hospital clock, which may mean you aren't covered. Plus, you're working under protocols that fall under Physicians of your hospital and are the hospital's protocols, so anything you do to patients of another facility might be considered out of scope since you may not be able to apply those protocols to the LTACH patients.
Anyway, according to CMS rules these patients must be considered transfers from another facility when they go from the LTACH unit to your ICU. They way I remember it, you cannot have separate policies for you in-hospital LTACH, and if all patients from another facility must go through the ER, then so must your LTACH patients. This was a while ago however and much of this may have changed, and I'm sure there are also many tricks for getting around these rules by now.