This is avoided in our system by having the Base Hospital (our medical direction) have a list of approved, designated Base Hospital Physicians who can answer the phone and provide orders. They have to provide their name and ID Number and the patch is recorded.
Thats what we have done; there is a list of approved medical advisors to the ambulance service who are our online consulatation should an Intensive Care Paramedic not satisfy the requirement for advice.
I found some minutes from a Clinical Management Group meeting way back in 2006 which said they (CMG) see themselves as offering three kinds (degrees) of advice to Ambulance Officers:
1. Am with the patient now, need advice immediately (cellphone)
2. Finished a job which went seriously wrong, need advice within the hour (cellphone or pager)
3. Something I'd like to discuss whenever you are free .... (email)
To give you a rough idea; I think #1 which is direct online consult about what to do for a patient now happens about once a day (out of 3,500 ambo's) whereas #2 is really a cover your *** I think we killed him sort of thing which I immagine is fairly rare. #3 is mostly dealt with by Clinical Managers and not the CMG directly any more.
I would personally only consider getting a Medical Advisor on the phone with me right now if I thought my treatment had actually killed a patient or there was some serious clinical risk that needed to be dealt with.
Not that I think it matters personally, but our Medical Advisors are part-time retained emergency or intensivist physicians who practice in the hospital as well as provide advice to the ambulance service. That said they all have an Ambulance pager or cellphone with them but it's often far easier to call the Watch Manager who is an Intensive Care Officer and speak with him, unless like I say, there is some hugely serious problem that requires a doctors input or to activate the CYA mechanisim.