Emergency Medical Facility Location And Allocation Considering Ambulance Busy Rate

After a sudden disaster,some basic service facilities in the affected area,such as roads and hospitals,may be severely damaged.Due to the surge of wounded in a sudden disaster,the current emergency medical facility capacities would be insufficient.A massive number of wounded will not be treated in hospital,which may lead to more death and may paralyze the existing medical service system.Therefore,rapid emergency medical response decisionmaking under these circumstances is of great significance to life-saving implications.To achieve quick response in the disaster,this paper addresses the issue of emergency medical facility location and ambulances allocation,as well as the casualty allocation.The temporary medical facilities are built to add addition medical capacity for the existing hospitals,a limited number of ambulances are allocated to these emergency medical facilities,and the casualties at the disaster area are allocated to emergency medical facilities.Considering the demand change under disasters,a multi-period integer programming model is proposed to make different decisions on the emergency medical facility location and ambulances allocation problem.Considering the ambulances availability as special medical resources,the queuing theory is introduced to calculate the ambulance busy rate.The objectives are to minimize the total response time and average waiting time of casualties over the search-and-rescue period.To solve this complex problem,a two-layer heuristic algorithm combining a simulated annealing algorithm and a genetic algorithm is used to solve the model.Then,the two-layer heuristic algorithm is improved by absorbing the tabu search into simulated annealing algorithm.The proposed model and algorithm are further verified in a case study of Chaoyang District in Beijing,and the numerical experiments demonstrate the effectiveness of our proposed model.Specifically,several findings are obtained based on the computational results: 1.It may not be optimal to allocate casualties to the nearest medical facility because of the limited facility capacity.As demand increases,the proportion of casualties allocated to the nearest medical facility will gradually decrease.2.The ambulances allocation result will fluctuate greatly with the demand rate change.The best ambulances allocation should be changed in each period.3.Increasing the number of ambulances and emergency medical facilities does not always lead to better performance.With a certain demand rate,the average waiting time of the casualties does not change significantly after the number of ambulances and emergency medical facilities reaches a certain threshold.