Location optimization of emergency medical services: Considering joint service coverage of ambulances and emergency centers

Emergency Medical Services (EMS) play an essential role in saving lives and improving health outcomes by offering immediate medical care to individuals who experience sudden illnesses or injuries. A complete EMS journey consists of two related trips: one from an EMS station to a scene (Trip 1), and the other from a scene to a definitive care location (Trip 2), where the service is coordinately provided by two types of facilities: EMS stations/ambulances and emergency centers (e.g., trauma centers or stroke centers) that are often affiliated with general hospitals. Current work on EMS location optimization considers only one trip (Trip 1 or Trip 2) which ignores the coordination between EMS stations and emergency centers, or the overall trip alone that overlooks the response time requirement. This paper proposed a spatial optimization model, the maximal coverage location problem based on joint coverage (MCLP-JC), for siting EMS stations and emergency centers simultaneously with a consideration of the two related trips. An empirical study of stroke center planning in Wuhan, China, is implemented to compare the proposed approach with the maximal coverage location problem based on overall coverage (MCLP-OC). The results demonstrate that the MCLP-JC can ensure more people being able to receive the first care from an ambulance within the response time requirement, which is critical to subsequent treatment at emergency centers and the odds of survival. The findings from the two scenarios regarding service relocation and expansion offer insights for future health facility planning.