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History of Air Medical and Air Ambulance Services in the United States


In 1926, the United States Army Air Corps used a converted airplane to transport patients from Nicaragua to an Army hospital in Panama, 150 miles away. The routine interhospital military use of airplanes1 dates to World War II, as does the first air evacuation of U.S. soldiers from the site of injury, which occurred in what was then Burma.

The routine medical evacuation mission of helicopters, however, evolved unintentionally during the Korean conflict in the 1950’s. Because roadways in the fighting front of Korea were often rough and indirect, they could not be relied upon for the rapid and gentle evacuation of troops to the field surgical units. Instead, helicopters on other missions would be rerouted to pick up the critically wounded and fly them quickly and smoothly, often in time to benefit from life- or limb-saving surgical care.

The Army, seeing this advantage over ground transportation, rapidly began testing dedicated medical helicopters. During the course of the war, over 22,000 troops were evacuated by helicopter. It is felt that rapid, smooth field evacuation and the specialized skills offered by surgeons seeing hundreds of patients earlier at the field hospitals contributed to a reduced mortality rate for wounded, hospitalized soldiers, compared with previous wars.

The Viet Nam conflict brought further sophistication to the same general concept: fast and smooth air evacuation of the critically injured to field surgery for stabilization. The aircraft changed, as did medical capabilities. Field emergency care and rapid evacuation for over 800,000 troops reduced the war-long mortality even further.

A theme from WWI through Viet Nam began to repeat: stabilize the critically wounded soldier in the field, provide advanced care enroute, and get the patient to a trauma-qualified surgeon in less than an hour, and the extent and impact of injury, including the likelihood of death, can be reduced.

In 1966, the landmark National Academy of Science white paper Accidental Death and Disability: The Neglected Disease of Modern Society underscored the profound impact of death and disability caused by injury, particularly car crashes. It also detailed a lack of coordinated response to injury, including the observation that “Helicopter ambulances have not been adapted to civilian peacetime needs.”

The National Academy of Science white paper contributed substantially to the development of the modern EMS system and its trauma care subsystem. Its impact was compounded by the influence of returning military units, and military medical helicopter pilots discharged to law enforcement and other public safety flying roles. These led to the dual-purpose adaptation of military and public safety helicopters to the evacuation of injured civilians, such as the Military Assistance to Safety & Traffic (MAST) program, established in 1970, and the Maryland State Police aviation program which in March, 1970, became “the first civilian agency to transport a critically injured trauma patient by helicopter.”

The first civilian hospital-based medical helicopter service was established in 1972 at St. Anthony’s Hospital in Denver, Colorado. By 1980, some 32 helicopter emergency medical services (HEMS) programs with 39 helicopters were flying more than 17,000 patients a year. By 1990, this grew to 174 services with 231 helicopters flying nearly 160,000 patients. Ten years later, 231 helicopter services with 400 aircraft were flying over 203,000 patients each year.10 By 2005, 272 services operating 753 rotor-wing (helicopter) and 150 dedicated fixed wing aircraft were in operation.  There are now approximately a half-million helicopter and fixed wing transports each year.

Historically, the typical helicopter EMS service has been operated by or affiliated with a hospital with one or two aircraft. In the past decade, many of these services have become independent, community-based resources with hospital affiliations. The rapid growth of AMS, particularly in the late 1980’s and again in the last 5 years, can be attributed to changes in the overall health care system. The need to quickly bring critically injured patients to surgical care brought AMS (mainly medical helicopters) into existence. In more recent years, the closure of rural hospitals because of reimbursement and other financial pressures, or their conversion to Critical Access Hospitals (CAH’s) with reduced services and fewer specialist physicians, has created large geographical gaps in the availability of specialized surgical resources. Unfortunately, these rural areas are also the location of the most serious car crashes and are where 60% of fatal crashes in the U.S. occur, a rate nearly double that of similar accidents in suburban or urban areas.

The use of aircraft with skilled medical crews helps to close these gaps and improves access to specialist care. As more time-dependent medical treatments (e.g. “clot-busting” drugs, angioplasty, or surgery for heart attacks or strokes) have been shown to improve patient outcomes, the absence of specialty care and physicians in these same areas continues to contribute to the increased use of aircraft to get patients rapidly to these life saving treatments at specialty hospitals.

Research in the early 1970’s reinforced the notion held by wartime physicians that, for the critically injured patient, surgical intervention in the first hour after injury was crucial. The notion of this “Golden Hour” has survived, with minor variation, to the present day. With this influence, the Accidental Death and Disability…white paper, and the fresh experience of military medical helicopter success in this arena, it is understandable that civilian HEMS adopted trauma as its predominant mission in its early years.

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