Likely this is the Freq/PL for the Local ER, where the AMB was talking to DHART for the LZ?? Northern New England, seems to use different PL's per Hospital on VHF, where Southern New England will generally patch thru CMED See if you can determine which Helo
Here are most of the New England Helo channels.
Medical Helicopters - Scan New England Wiki
VT had implemented one of the VTAC's as the Official LZ, but guess if the Hosp is Pre-Designated they use the HOSP Freq. 159.4725 (formerly VTAC 4, now VTAC 14)
http://vermontcommunications.vermont.gov/sites/vcomm/files/VCOMMInteroperabilityGuide.pdf
The PL tone for the local hospital, CVH (Central Vermont Hospital) is "no tone" on frequency 155.3400. The PL tone for the local ambulance(s) servicing CVH is PL tone 97.4 on that same frequency.
I know when I was listening to the EMS getting toned out, once one of them was on scene and saw the patient, they asked if Dhart was available to transport.
I was busy with other things at the time so I didn't sit right next to my scanner to listen in on what was happening but when I finally got back to it, I heard squelch break on that 155.3400 PL 186.2 with either the medic, or the pilot(?) from the helo explaining their situation regarding the patients status.
The one thing that distinctively stuck out during his transmission was what sounded to me like the whining of a motor coming over the scanner. It was quite noticeable.
I'm almost certain it was the Dhart helicopter that I heard talking about having a patient on board with a severe compound leg fracture with other injuries.
Now maybe the Dhart helicopter was talking to Dartmouth Hitchcock hospital when I heard that transmission, I don't know that as I don't know what Dartmouth's hospital frequencies are.
Does VT have a MedChopper or is it Dhart
Whenever there was a need for a quick transport of an injured patient from any kind of accident in and around my area, the EMS has always asked for a Dhart transport. I've never heard anyone ask for a MedChopper. I've never heard of "MedChopper" until this thread from your post MaineRadioMan.