The development of emergency medical dispatch in the USA: a historical perspective.

Emergency medical dispatch has evolved over the last 25 years from a system designed to limit abuse of the emergency medical services (EMS) to a sophisticated part of the total EMS response. Its current goal is to send the right thing to the right person at the right time in the right way and to do the right thing until help arrives. The historical development of emergency medical dispatch in the USA is outlined decade by decade. In addition, the current state of emergency medical dispatch is reviewed and future directions are discussed.