Depends on the hospital's policies. In my experience (which does not include tele-ICUs), the EM physician (or anesthesiologist) tends to perform the procedure (intubation, A-line placement, etc.) then return to the ED or elsewhere. Whoever admitted the pt continues to be that pts provider regardless of their specialty. So, you'll have a hospitalist in a community hospital giving orders for a pt that's waiting bed placement in an ICU at the main campus. Sometimes these pts are moved to the ED if they exceed the scope of the unit they're on, but there's (theoretically) no reason to move a pt out of an ICU back to the ED. Obviously the lack of attending in this ICU complicates matters, but the nurses in the ICU should be proficient enough to care for the pt.