Department of Emergency Medicine, Singapore General Hospital, Singapore.
Acad Emerg Med. 2010 Sep;17(9):951-7. doi: 10.1111/j.1553-2712.2010.00860.x.
This study aimed to determine if a deployment strategy based on geospatial-time analysis is able to reduce ambulance response times for out-of-hospital cardiac arrests (OOHCA) in an urban emergency medical services (EMS) system.
An observational prospective study examining geographic locations of all OOHCA in Singapore was conducted. Locations of cardiac arrests were spot-mapped using a geographic information system (GIS). A progressive strategy of satellite ambulance deployment was implemented, increasing ambulance bases from 17 to 32 locations. Variation in ambulance deployment according to demand, based on time of day, was also implemented. The total number of ambulances and crews remained constant over the study period. The main outcome measure was ambulance response times.
From October 1, 2001, to October 14, 2004, a total of 2,428 OOHCA patients were enrolled into the study. Mean ± SD age for arrests was 60.6 ± 19.3 years with 68.0% male. The overall return of spontaneous circulation (ROSC) rate was 17.2% and survival to discharge rate was 1.6%. Response time decreased significantly as the number of fire stations/fire posts increased (Pearson χ(2) = 108.70, df = 48, p < 0.001). Response times for OOHCA decreased from a monthly median of 10.1 minutes at the beginning to 7.1 minutes at the end of the study. Similarly, the proportion of cases with response times < 8 minutes increased from 22.3% to 47.3% and < 11 minutes from 57.6% to 77.5% at the end of the study.
A simple, relatively low-cost ambulance deployment strategy was associated with significantly reduced response times for OOHCA. Geospatial-time analysis can be a useful tool for EMS providers.
本研究旨在确定基于地理时空分析的部署策略是否能够缩短城市急救医疗服务（EMS）系统中院外心脏骤停（OHCA）的救护车反应时间。
对新加坡所有 OHCA 的地理位置进行了观察性前瞻性研究。使用地理信息系统（GIS）对心脏骤停的位置进行了现场映射。实施了渐进式卫星救护车部署策略，将救护车基地从 17 个增加到 32 个。根据一天中的时间，根据需求改变了救护车的部署，以满足需求。在研究期间，救护车和工作人员的总数保持不变。主要观察指标为救护车反应时间。
从 2001 年 10 月 1 日至 2004 年 10 月 14 日，共有 2428 名 OHCA 患者入组研究。发病时平均年龄为 60.6±19.3 岁，男性占 68.0%。总体自主循环恢复（ROSC）率为 17.2%，出院存活率为 1.6%。随着消防站/消防站数量的增加，反应时间显著缩短（Pearson χ(2) = 108.70，df = 48，p < 0.001）。OHCA 的反应时间从研究开始时每月中位数 10.1 分钟降至研究结束时的 7.1 分钟。同样，反应时间<8 分钟的病例比例从研究开始时的 22.3%增加到研究结束时的 47.3%，<11 分钟的比例从 57.6%增加到 77.5%。
简单、相对低成本的救护车部署策略与 OHCA 的反应时间显著缩短相关。地理时空分析可以成为 EMS 提供者的有用工具。
