Stretcher bearers removing a wounded soldier from Vaux, France, July 22, 1918 U.S. Signal Corps photo. Four soldiers carry a wounded soldier on a stretcher past a bombed-out building. The United States Army Ambulance Service was a unit of the United States Army during World War I. It was established by General Order No. 75 of the War Department in May 1917. It primarily provided medical services to the French and Italian Armies during the War. It incorporated the volunteer sections of the American Field Service, which had been formed before the American entry into the war.