<P> In the United States, emergency medical services (EMS) provide out - of - hospital acute medical care and / or transport to definitive care for those in need . They are regulated at the most basic level by the federal government, which sets the minimum standards that all states' EMS providers must meet, and regulated more strictly by individual state governments, which often require higher standards from the services they oversee . </P> <P> Wide differences in population density, topography, and other conditions can call for different types of EMS systems; consequently, there is often significant variation between the Emergency Medical Services provided in one state and those provided in another . </P> <P> EMS delivery in the US can be based on various models . While most services are, to some degree, publicly funded, the factor which often differentiates services is the manner in which they are operated . EMS systems may be directly operated by the community, or they may fall to a third - party provider, such as a private company . The most common operating models in the U.S. include: </P>

In the united states it is becoming common for ems to do this when they arrive