Injury-based Geographic Access to Trauma Centers.

OBJECTIVE: Previous studies examining access to trauma care use patient residence as a proxy for location and need for services, which could result in a flawed understanding of access to trauma centers. The objective of this study was to examine the geographic access of the U.S. population to trauma centers based on trauma incident locations.

METHODS: We conducted a cross-sectional study using 9-1-1 emergency medical services activations associated with traumatic injury from the 2014 National Emergency Medical Services Information System and trauma centers participating in the 2014 American Hospital Association Annual Survey. The measures included the percentage of trauma incidents that could reach a trauma center within 60 minutes by ground ambulance, capacity-to-demand ratio for each trauma center, and overall trauma care accessibility ratio for each U.S. zip code.

RESULTS: A total of 92.9% of all trauma incidents could be transported to an existing trauma center within 60 minutes by ground ambulance, and 85.3% could be transported to a Level I or II trauma center within this time frame in the 32 study states. While 94.7% of trauma incidents in the Northeast area could be transported to a Level I or II trauma center within a 60-minute driving time, the capacity-to-demand ratios of trauma centers in this region were low, indicating high utilization of those trauma center resources. By using the accessibility measure, we found that some Midwestern and Southern states had higher amounts of accessible trauma center resources relative to the number of injuries than Northeastern states.

CONCLUSIONS: These findings suggest that greater access to trauma care and significant variations can be observed throughout the 32 study states when using trauma incident location rather than patient residence to calculate access to trauma care. The proposed capacity-to-demand ratio and accessibility ratio can be applied to many other needs assessments in health care.