This shows a total ignorance of the issue. Do a little reseach and come back to have a worthwhile conversation. I agree with Ventmedic, we need to get EMS up to a national standard and not local standards. I also agree with the person that said that cost may be prohibitive. These machine can be pretty expensive (say $20k in some cases). I can also not see using them out of the ambulance. Keep them in the ambulance and use them once the pt is on board.
I can see them having a place in EMS. Let's just look at the FAST exam (Focus Abdominal Sonography in Trauma, for those that were wondering). You pull up to a scene where a pt had had an abd trauma (MVA, kicked by a horse, whatever). They have good vitals because they are compensating for their bleed. You put the US on and find free fluid in Morrison's Pouch. Instead of taking the pt to your community hospital you will redirect to the trauma center. A negative US should not loosen up your pucker factor. The FAST exam looks at four spots where fluid commonly collects. Sometime the blood does not collect in these areas, so you still need to have a high index of suspicion. You can also use the FAST exam to assess a hypotensive pt with abd pain for free fluid. You can look at the Aorta to look for aneurysms. You can look for pericardial effusions and treat tamponade. OB is also another area you can use the US. You can have a pregnant woman who has not had her first appt yet. She develops pelvic pain and you, the astute medic, put the US on her and realize there is no fetus in the uterus. Where could it be? Could be an ectopic. This may also change where you take the pt and how quickly they get seen at your final destination.
As to the comment about spending time with someone to perfect your technique, US is pretty easy to learn. As a physician I never spent any time with someone else other than my attendings. You learn them best by doing them and on the machine you are going to use. The quality of the machines that we use in the ER and that would be used in the field are much less than those used by the US techs. It would be like learning to drive a motorcycle by using a Suburban.