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WSU Medical School

Training Level

Medical Student


Wayne State University


Introduction: Recently, Detroit has seen a gradual improvement in Emergency Medical Service (EMS) response times. The historically long response times have been implicated in contributing to the high rates of private vehicle transportation (PVT) in Detroit, up to 3 times higher than the national average. This study tests the hypothesis that as EMS arrival times improve, the utilization of PVT in Detroit would decrease. Methods: This is a retrospective study at an academic, regional, Level 1 trauma center in Detroit over 28 months. Inclusion criteria were trauma patients that were admitted, transferred out of hospital, or died. Patients transferred from outside hospitals were excluded (N=2285). The data were obtained from hospital data registry and the city of Detroit’s performance dashboards. Correlation studies were then conducted between average EMS response time and percent PVT utilization and repeated for subgroup analysis by injury severity and trauma cause, and linear regression was conducted if correlation was significant.Results: Though correlation studies show a decline in EMS response time over 28 months with an R2 value of 0.817, there was a weak relationship between PVT usage and time (R2=0.017) and between PVT usage and EMS response time (R2=0.0058). Similar results were seen with subgroup analysis, with the largest R2 value being 0.273 in serious injuries. Conclusions: Despite continued improvement in EMS response times, we did not observe a corresponding decrease in PVT utilization. Potential explanations include a delay in this observation due to a long history of long EMS response time, the general public being unaware of this improvement, or the notion that factors other than historically high EMS arrival times play into this regional phenomenon which we explore through first-responder interviews and patient surveys.

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Trauma Patients Still Use Private Vehicle Transport Despite Improvement in EMS Response Times