Sunnybrook Research Institute, Sunnybrook Health Sciences Center, Toronto, Ontario, Canada.
Clinical Epidemiology Program, Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Ontario, Canada.
JAMA Surg. 2019 Apr 1;154(4):286-293. doi: 10.1001/jamasurg.2018.5097.
Motor vehicle crashes (MVCs) are a leading public health concern. Emergency medical service (EMS) response time is a modifiable, system-level factor with the potential to influence trauma patient survival. The relationship between EMS response time and MVC mortality is unknown.
To measure the association between EMS response times and MVC mortality at the population level across US counties.
DESIGN, SETTING, AND STUDY POPULATION: This population-based study included MVC-related deaths in 2268 US counties, representing an estimated population of 239 464 121 people, from January 1, 2013, through December 31, 2015. Data were analyzed from October 1, 2017, through April 30, 2018.
The median EMS response time to MVCs within each county (county response time), derived from data collected by the National Emergency Medical Service Information System.
The county rate of MVC-related death, calculated using crash fatality data recorded in the Fatality Analysis Reporting System of the National Highway Traffic Safety Administration.
During the study period, 2 214 480 ambulance responses to MVCs were identified (median, 229 responses per county [interquartile range (IQR), 73-697 responses per county]) in 2268 US counties. The median county response time was 9 minutes (IQR, 7-11) minutes. Longer response times were significantly associated with higher rates of MVC mortality (≥12 vs <7 minutes; mortality rate ratio, 1.46; 95% CI, 1.32-1.61) after adjusting for measures of rurality, on-scene and transport times, access to trauma resources, and traffic safety laws. This finding was consistent in both rural/wilderness and urban/suburban settings, where a significant proportion of MVC fatalities (population attributable fraction: rural/wilderness, 9.9%; urban/suburban, 14.1%) were associated with prolonged response times (defined by the median value, ≥10 minutes and ≥7 minutes, respectively).
Among 2268 US counties, longer EMS response times were associated with higher rates of MVC mortality. A significant proportion of MVC-related deaths were associated with prolonged response times in both rural/wilderness and urban/suburban settings. These findings suggest that trauma system-level efforts to address regional disparities in MVC mortality should evaluate EMS response times as a potential contributor.
机动车事故（MVC）是一个主要的公共卫生关注点。紧急医疗服务（EMS）响应时间是一个可修改的系统级别因素，有可能影响创伤患者的生存。EMS 响应时间与 MVC 死亡率之间的关系尚不清楚。
在全美国县级层面上，测量 EMS 响应时间与 MVC 死亡率之间的关联。
设计、设置和研究人群：这项基于人群的研究纳入了 2013 年 1 月 1 日至 2015 年 12 月 31 日期间，美国 2268 个县与 MVC 相关的死亡病例，代表了估计为 239464121 人的人群。数据于 2017 年 10 月 1 日至 2018 年 4 月 30 日进行分析。
每个县内的 MVC 相关 EMS 响应时间中位数（县响应时间），由国家紧急医疗服务信息系统收集的数据推导得出。
使用国家公路交通安全管理局的伤亡分析报告系统中记录的撞车死亡数据计算的 MVC 相关死亡率。
在研究期间，确定了 2268 个美国县内 2214480 次救护车对 MVC 的响应（中位数，每个县 229 次响应[四分位距（IQR），每个县 73-697 次响应]）。县响应时间中位数为 9 分钟（IQR，7-11）分钟。调整农村/野外和城市/郊区环境、现场和运输时间、获取创伤资源和交通安全法规等措施后，较长的响应时间与 MVC 死亡率较高显著相关（≥12 分钟与 <7 分钟；死亡率比，1.46；95%CI，1.32-1.61）。在农村/野外和城市/郊区环境中，这一发现是一致的，其中 MVC 死亡率的很大一部分（农村/野外，9.9%；城市/郊区，14.1%）与较长的响应时间相关（通过中位数定义，分别为≥10 分钟和≥7 分钟）。
在美国 2268 个县中，较长的 EMS 响应时间与 MVC 死亡率较高相关。在农村/野外和城市/郊区环境中，很大一部分 MVC 相关死亡与延长的响应时间相关。这些发现表明，应对 MVC 死亡率区域差异的创伤系统层面工作应将 EMS 响应时间作为一个潜在的影响因素进行评估。
