International EMS systems: The United States: past, present, and future.

Emergency medical services (EMS) is an organised system designed to transport sick or injured patients to the hospital. Though EMS system configurations can be quite varied in design depending on locale, we provide an overview of EMS as it has evolved and is currently modelled in the US. We outline the history of EMS in the US, including the major events and legislation that shaped the current models that are in existence. We provide an overview of provider training, system design, system funding, and dispatch issues. The concepts of medical direction for physician surrogates, as well as EMS as it relates to specialty care are also elucidated.