Here in the Philadelphia area the areo medical choppers use CTAF 123.0250 and they used to use 123.0500 for air to air with other choppers (Police, News Media etc.) I don't monitor the airport freqs but I have heard PennStar on Philadelphia Int'l Airport tower (118.5) I'm sure they use the local airport tower, approach, departure freqs in your area and try the 123 freqs they are for helicopters only.
Joe