Emergency War Surgery NATO Handbook: Part III: General Considerations of Wound Management: Chapter XIII: Aeromedical Evacuation
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Helicopters are versatile, maneuverable aircraft normally utilized to evacuate injured patients short distances rapidly. The flying time of currently deployed helicopter ambulances is about three hours with a range of 250-300 miles. Utilization of these aircraft results in the casualty reaching wellequipped medical facilities in a matter of minutes. Casualties with grave injuries that would have been fatal without the utilization of rapid air transportation reach operating rooms. The foregoing was repetitively demonstrated in Vietnam where, due to the relatively short distances involved, the battalion aid station was for the most part overflown, with direct evacuation from the battlefield to definitive care facilities having surgical capabilities.
The effects of this rapid field aeromedical evacuation system were twofold. On the one hand, many casualties, who in previous conflicts would have died of their wounds while awaiting or undergoing surface medical evacuation, reached definitive care facilities and were salvaged. Without taking anything away from the superb performance of corpsmen, nurses, and surgeons, this very substantial salvage of human life was in large measure directly attributable to the gallant, selfless professionalism of the "can do" air ambulance flight crews.
On the other hand, rapid field aeromedical evacuation of fresh battle casualties attributed at least in part to the slightly increased hospital mortality experience in Vietnam. For example, in World War II, with no field aeromedical capability, 4.5% of those wounded in action (WIA) and subsequently hospitalized died of their wounds. In the Korean conflict, with its limited utilization of field aeromedical evacuation but better medical-technical capabilities, the hospital mortality of this same group of casualties declined to 2.5%. However, in Vietnam, with its even further advanced medical-technical capabilities but almost universal application of rapid field aeromedical evacuation, hospital mortality of WIAs increased to 3.5%. This increased WIA hospital mortality rate is thought to be due, at least in part, to early hospital presentation of a small but significant number of casualties with mortal wounds. These represent casualties that would never have arrived alive at medical treatment facilities in previous conflicts.
With the availability of helicopter evacuation from the battlefield, the decision to fly casualties directly to hospitals depends on five variables: the clinical status of the casualty, the flying time, the weather conditions, the casualty generation rate or load, and the tactical situation. Where casualty generation is heavy and helicopter resources are limited, casualties can be transported by air or by land from the battlefield to nearby clearing stations. After triage and initial resuscitation, they will be moved to more definitive facilities in order of their clinical priority. Even when the hospital is relatively close to the battlefield, the division clearing station can serve as a buffer when casualty loads temporarily overwhelm a hospital's capability. It must be constantly borne in mind that the availability of rapid transportation by air does not alter, in any way, the necessity for correct application of surgical principles. Experience has shown that field aeromedical evacuation functions most efficiently and reliably when these assets are dedicated to their medical mission and are under direct medical command and control.
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