As emt_531 mentioned, the hospital you are referring to is likely used for flights which transport patients OUT of the facility. In that case, the patient report would be given on "company" channels. For example, when a patient is to be transferred from our local hospital, the helicopter is provided patient information on the dispatch frequency of the respective air ambulance service.
In the event there is a need for the helicopter to meet an EMS unit for an immediate transfer to a trauma center, you will most likely hear an abbreviated patient report on one of the VIPER channels such as "LZ Central." That is usually just an update of any changes in the patient's condition since the initial dispatch, and is given by a local firefighter or EMT.
Since helicopters are aircraft, you may also hear them on aviation frequencies as well. When they are transitioning through the area just west of here, the pilot will announce his intentions on the Common Traffic Advisory Frequency (CTAF) for the nearby airfield.
The best advice would be to determine which service(s) land on the helipad on a fairly regular basis. Plug in all their channels (dispatch and ops), and it probably won't be long before you hear radio traffic. Since it appears that your local hospital is part of the UNC Health Care system, that would be a great place to start listening. UNC AirCare Dispatch is on VIPER Talkgroup 52342, and I have also heard traffic on 52340, UNC AirCare Ops.
Others may chime in with more information that is specific to your area, but this should get you started.
