In the middle of its military campaign against Iraq, the Marine Corps is establishing an innovative helicopter-borne casualty evacuation system for injured U.S. forces and Iraqis.

"There has been no doctrine for this in the past" and no time to set up an organizational structure, said a Navy captain serving as the assistant wing surgeon for casualty evacuation at the 3rd Marine Air Wing. Without established procedures, officials involved in the operation are making up many of the rules as they go along.

For instance, in the first transport of wounded Iraqis, the patients were not restrained. But after Iraqi soldiers in subsequent days faked battlefield surrenders, medical personnel decided they should be restrained on the helicopters. Referring to the first mission, a medical official said, "We think perhaps we made a mistake and got away with it."

The Marines have dedicated several CH-46E Sea Knight helicopters in four squadrons (HHM-164, -162, -268, -364) to the mission with each unit assigned to a specific regimental combat element. A total of 32 medical personnel are assigned to the casualty evacuation mission, eight per squadron. Two helicopters with two medical personnel each are deployed close to the ground element for 2-4 day shifts. Another two CH-46Es are held in reserve, with two medical personnel each.

Each helicopter theoretically can accommodate up to nine litters, although, practically, the number is lower. Medical personnel have surveyed historical data to determine the kinds of injuries they are likely to treat. The most probable are bleeding of extremities, which caused 2,500 "unnecessary deaths" in Vietnam, the surgeon said. Chest injuries rank second.