J. B. Brown1, M. R. Rosengart1, T. R. Billiar1, A. B. Peitzman1, J. L. Sperry1 1University Of Pittsburgh,Surgery,Pittsburgh, PA, USA
Introduction: Trauma systems improve outcome; however it is unclear how geographic organization of these resources affects outcome. The objective was to evaluate correlation of geospatial trauma system resources and injury mortality in Pennsylvania (PA).
Methods: Trauma centers and helicopter emergency medical service (HEMS) bases in PA were mapped. Scene mortality rates were obtained at the county-level from the PA trauma registry. Service areas were generated for HEMS and ground EMS (GEMS) transport to a trauma center within 60min, accounting for response and scene times. Trauma system resources in each county including number of trauma centers or HEMS bases, proportion covered by HEMS and GEMS service areas were categorized as high or low by median values. Mortality was compared between high and low trauma system resources. Local Moran's I was used to identify geographic outlier clusters. Geographically weighted regression (GWR) evaluated association of mortality with trauma system resources, adjusting for county-level demographics, injury severity, and socioeconomic factors. Correlation of weighted mortality and resources from GWR was examined.
Results: 63,706 blunt and 6,260 penetrating patients were included. Blunt mortality was spatially autocorrelated (Moran I 0.22, p<0.01). Fig 1 demonstrates blunt mortality with trauma system resources. High HEMS coverage was associated with lower mortality (4.2% v 5.7%, p=0.04). Mortality was not associated with high number of trauma centers/HEMS bases (p=0.20) or high GEMS coverage (p=0.07). Outlier clusters with high mortality and low resources were seen in southcentral and northwest PA (p<0.01), while clusters of low mortality and high resources were seen in southwest and southeast PA (p<0.05). In GWR, mortality was inversely correlated with HEMS coverage (ρ=-0.71, p<0.01), GEMS coverage (ρ=-0.69, p<0.01), and number of trauma centers/HEMS bases (ρ=-0.38, p<0.01). Penetrating mortality was also autocorrelated (Moran I 0.36, p<0.01). High number of county trauma centers/HEMS bases was associated with lower mortality (13% v 26%, p<0.01), as was high HEMS coverage (13% v 25%, p<0.01) and high GEMS coverage (13% v 21%, p<0.01). Outlier clusters were similar to blunt injury. In GWR, mortality was inversely correlated with number of trauma centers/HEMS bases (ρ=-0.64, p<0.01) and HEMS coverage (ρ=-0.47, p<0.01), but not GEMS coverage (ρ=-0.23, p=0.07).
Conclusion: Geospatial organization of trauma system resources is correlated with injury mortality in PA. Different geospatial resources may be more important by mechanism. These results may aid trauma system planning and identify local areas to target trauma system resources.
