Good question. As with anyone who is going to be inpatient in a hospital there must be an accepting physician. This is a doctor who is willing to accept the responsibility for the patient and to call treatment orders to the nursing staff.
How does the doctor decide whether or not he wants to assume this responsibility?
Though there may be some variations, the normal procedure is for the evaluator to call the hospital and describe the case to one of the staff: could be a nurse or a counselor. That person in turn calls the doctor and presents the information. The doctor can refuse, accept, or ask for more tests or information. For example, let's say there's a history of heart disease or diabetes, the doctor may request at a minimum blood sugar and vitals. The doctor may ask for anything they want (more on this later).