There was a televised news report where AMR in southwestern Indiana was using a cell phone app for all dispatching of ambulance and wheel chair nonemergency transports. The two way radios were going to be used only for back up. When a call for service was received by dispatch the information plus mapped location was sent to the ambulance crew via cell phones. All other related information was transmitted through the cell phone. I’ve heard other regions covered by American Medical Response (AMR) are using the same system.
The wiki page for St Louis County showed AMR using digital dispatching. There might be very limited voice traffic to be heard on any trunked or conventional radio system. I’m not sure if Abbot AMR is related to AMR in southern Indiana and Kentucky. There have been a couple of threads discussing AMR radio traffic disappearing around Louisville and Lexington IIRC.