Sean Shao Wei Lam1, Ji Zhang2, Zhong Cheng Zhang3, Hong Choon Oh4, Jerry Overton5, Yih Yng Ng6, Marcus Eng Hock Ong7. 1. Health Services Research and Biostatistics Unit, Division of Research, Singapore General Hospital, Singapore. Electronic address: lam.shao.wei@sgh.com.sg. 2. Department of Emergency Medicine, Singapore General Hospital, Singapore. Electronic address: zhang.ji@sgh.com.sg. 3. Department of Emergency Medicine, Singapore General Hospital, Singapore. Electronic address: zhongcheng1986@gmail.com. 4. Health Services Research, Eastern Health Alliance, Singapore. Electronic address: hong.choon.oh@easternhealth.sg. 5. International Academies of Emergency Dispatch, Salt Lake City, UT, USA. Electronic address: Jerry.Overton@emergencydispatch.org. 6. Medical Department, Singapore Civil Defence Force, Singapore. Electronic address: ng_yih_yng@scdf.gov.sg. 7. Department of Emergency Medicine, Singapore General Hospital, Singapore; Health Services and Systems Research, Duke-NUS Graduate Medical School, Singapore. Electronic address: marcus.ong.e.h@sgh.com.sg.
Abstract
OBJECTIVES: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.
OBJECTIVES: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.
Authors: James P Byrne; N Clay Mann; Mengtao Dai; Stephanie A Mason; Paul Karanicolas; Sandro Rizoli; Avery B Nathens Journal: JAMA Surg Date: 2019-04-01 Impact factor: 14.766