I will go ahead and say that NONE of the hospitals or clinics in Marion County use IHERN any longer.
Every major facility in Indianapolis-Marion County that I am familiar with does in fact maintain VHF capability on site. I am responsible for the care and feeding of one of these stations, a hundred watt MTR 3000 on 155.34, and I can tell you for a fact it gets used every day.
Standard practice for most facilities in Marion County is to have a minimum of two channels, either both on a console or one or two desksets (one deskset per channel if they use two). Usually this is whatever EMS-Mx DPSC system talkgroup is assigned to that facility, and VHF IHERN "Local" which is 155.34 NFM CSQ.
Typically, VHF IHERN is used to communicate pre-arrival with private ambulance services, air medical services, or out-of-county EMS that may not have DPSC (MECA) capability. The patch from VHF conventional to the DPSC system talkgroup mainly serves for interoperability purposes. As far as I know, it is wide open carrier squelch and repeats everything it hears on VHF to the DPSC talkgroup.
What does
not get used in Marion County, as far as I know, is anything EMS-to-hospital on the IPSC (SAFE-T) system. The ISDH talkgroup HOSPITAL-N serves as the intrahospital communications talkgroup, fairly analogous to the old IHERN Regional (155.28) but in practice the only time it is used is for the monthly drills put on by the various ISDH districts.
If one hospital needs to talk to another, they usually just call on the phone...