I'm a surgical nurse that floats to our ED at times, so don't take my word for book, verse and chapter of THE BOOK, but here goes.
I our rural, southeast Ohio hospital (level III trauma center), there seems to be around two tech's on a shift.
The shifts in our ED overlap, some on 8's, 10's or 12 hour shifts, or part of any.
The techs, help with splints, take vitals, run for things, do ekg's and blood draws among some other their other duties.
The one's I have had a chance to work with are very good at their job, and I for one, rely on them.
I hope that helps some.
Wishing I had something cool and thought provoking to sign off with.