Fig. 3

Numbers of patients in regional fire departments and their corresponding regional communication command section. Black circles indicate the base hospital (Dokkyo Medical University Hospital), triangles indicate the other four tertiary emergency centers, and yellow circles indicate the 12-communication command sections of fire department. The base hospital is mainly responsible for medical controlling in the D, E, and I areas, while the J area is jointly controlled by the base hospital and a tertiary emergency center. “Others” were those who requested Tochigi HEMS from two neighboring prefectures on the east (Ibaraki) and west (Gunma) by virtue of the agreement of Northern Metropolitan Wide-Area Cooperation