Well I can tell you, medic one air uses 155.340, The nationwide simplex frequency for all calls, I've heard it myself, Dispatch is the same as regular medic one ambulance frequencies, Here's what I think you're looking for though...
453.10000 458.10000 WPKE744 RM Medic One Ambulance FM EMS Dispatch
For chopper to hospital, Usually Air Evac will use either the nationwide simplex of 155.340 OR whichever channel the hospital ambulance traffic uses..
But thier dispatch channel for Jonesboro and several of the AE helicopters are on the forrest city tower..
153.60500 BM 051 DPL Forrest City Tower FM EMS-Talk
ALL OF THESE ARE REGISTERED TO EMERSON AMBULANCE, IT'S NOT IN THE DATABASE, I located it from the FCC database...Not sure which one of these they use but all of them are active licenses.. Hope this helps, Let me know if you hear anything on them, Just leave it here or send me a pm.