docfos- I think you will find that different institutions have different policies regarding when consultants are called. and like everything in medicine, it can be very attending dependent.
In general, it is the job of the EP to stabilize a patient, determine the cheif complaint, begin a workup based on the likely diagnosis, with particular emphasis on life threatening (or if left untreated, life threatening outcomes). And then based on the H&P, initial work up, the EP will then decide who, if any, a consult is needed.
Now, take belly pain. I just heard an interesting story from a fellow from a cali program. The surgeons and radiologists decided that the EP's were ordering entirely to many CT's. The surgeons felt that they were better able to decide who needed a CT and who didn't. And thus a new policy was initiated that ALL pt's with abdominal pain had to be seen by surgery before anything was ordered. (labs, rads, etc) Needless to say, this lasted approximately 3 weeks before the surgeons realized that an INCREDIBLE amount of patients are dealt with without CT's and without surgical consult.
So, the autonomy of the EP is very broad. You will decide what consultants you want, when you want them, and you will work in conjunction with them while the patient is in the ED.
You will often manage your ICU patients (especially in a residency hospital) as if there is an emergent issue, the medicine residents are usually busy on the floor and can't get down in time to deal with it.
Hope that helps.