Lam Sean Shao Wei, Zhang Ji, Zhang Zhong Cheng, Oh Hong Choon, Overton Jerry, Ng Yih Yng, Ong Marcus Eng Hock
Health Services Research and Biostatistics Unit, Division of Research, Singapore General Hospital, Singapore.
Department of Emergency Medicine, Singapore General Hospital, Singapore.
Am J Emerg Med. 2015 Feb;33(2):159-66. doi: 10.1016/j.ajem.2014.10.044. Epub 2014 Nov 8.
Dynamically reassigning ambulance deployment locations throughout a day to balance ambulance availability and demands can be effective in reducing response times. The objectives of this study were to model dynamic ambulance allocation plans in Singapore based on the system status management (SSM) strategy and to evaluate the dynamic deployment plans using a discrete event simulation (DES) model.
The geographical information system-based analysis and mathematical programming were used to develop the dynamic ambulance deployment plans for SSM based on ambulance calls data from January 1, 2011, to June 30, 2011. A DES model that incorporated these plans was used to compare the performance of the dynamic SSM strategy against static reallocation policies under various demands and travel time uncertainties.
When the deployment plans based on the SSM strategy were followed strictly, the DES model showed that the geographical information system-based plans resulted in approximately 13-second reduction in the median response times compared to the static reallocation policy, whereas the mathematical programming-based plans resulted in approximately a 44-second reduction. The response times and coverage performances were still better than the static policy when reallocations happened for only 60% of all the recommended moves.
Dynamically reassigning ambulance deployment locations based on the SSM strategy can result in superior response times and coverage performance compared to static reallocation policies even when the dynamic plans were not followed strictly.
在一天中动态重新分配救护车部署地点以平衡救护车的可用性和需求，可有效减少响应时间。本研究的目的是基于系统状态管理（SSM）策略对新加坡的动态救护车分配计划进行建模，并使用离散事件模拟（DES）模型评估动态部署计划。
基于地理信息系统的分析和数学规划，利用2011年1月1日至2011年6月30日的救护车呼叫数据，制定基于SSM的动态救护车部署计划。使用包含这些计划的DES模型，在各种需求和出行时间不确定性下，比较动态SSM策略与静态重新分配策略的性能。
严格遵循基于SSM策略的部署计划时，DES模型显示，与静态重新分配策略相比，基于地理信息系统的计划使中位响应时间减少了约13秒，而基于数学规划的计划使中位响应时间减少了约44秒。当仅对所有建议移动的60%进行重新分配时，响应时间和覆盖性能仍优于静态策略。
与静态重新分配策略相比，基于SSM策略动态重新分配救护车部署地点，即使不严格遵循动态计划，也能带来更好的响应时间和覆盖性能。
