Aeromedical retrieval of trauma patients: Impact of flight path model on estimates of population coverage.

BACKGROUND: The aim of this study was to compare the impact of different flight path models on the calculated population coverage of aeromedical retrieval systems, using the state of Alabama as a case study. METHODS: Geospatial analysis of U.S. Census Bureau population data using helicopter bases and trauma centers as foci of either circular or elliptical coverage areas. RESULTS: Circular isochrone models around helicopter bases or trauma centers suggest that the entire population of Alabama could reach a level I or II trauma center within 60 min. Elliptical isochrones, incorporating outbound and inbound flights, suggest that only 78.8% of the population have ready access to level I or II trauma centers. CONCLUSION: While all three flight path models described have some validity and utility, simplistic circular flight time isochrones around trauma centers and helicopter bases provide overly optimistic estimates of population coverage. The elliptical model provides a more realistic evaluation.

Population Coverage of Trauma Systems: What Do Helicopters Add?

Trauma is a time-critical condition. Helicopters are thought to enhance the accessibility to trauma centers, but this benefit is poorly quantified. The aim of this study was to conduct a geographical analysis of the added benefit provided by helicopters, over ground transport. This study uses geospatial analysis. Helicopter bases and Level I and II designated trauma centers were geocoded. 60-minute drive-time and elliptical flight-time isochrones were mapped with ArcGIS™ (Esri, Redlands, CA). Calculations included allowance for mission ground time (MGT). We compared the proportion of the population that could be taken to Level I and II trauma centers, within 60 minutes, by road and by air. Using a 30-minute MGT model, helicopters permit 279,317 additional residents (5.8%) access to a Level I trauma center within 60 minutes. Using the 20-minute MGT model, 1,089,177 more residents (22.8%) would have access to Level I trauma center care. The benefits were marginally greater for access to Level I and II trauma center care. Helicopters enhance access to specialist trauma center care, but the benefit is small and dependent on MGT. Consideration should be given to the siting of helicopters, particularly in relation to trauma patients, MGT, and the timely response of EMS when determining the triage for helicopter transport.

Use of helicopters for retrieval of trauma patients: A geospatial analysis.

BACKGROUND: Helicopters are widely used to facilitate the transport of trauma patients, from the scene of an incident to the hospital. However, the use of helicopters may not always be appropriate. The aim of this project was to conduct a geospatial analysis of helicopter transport to a Level I trauma center. METHODS: Retrospective geospatial analysis of trauma registry data, 2013 to 2018. We included all adult (≥16) trauma patients brought to the trauma center directly from the scene. Data were geocoded and analyzed using arcGIS. Drive times and flight times were calculated using Google Maps. Flight times included the time required to reach the incident location. RESULTS: Two thousand eight hundred ninety-three patients were identified, and 1,911 had incident locations recorded and were therefore included in the analysis. The median age was 41 years (interquartile range [IQR], 27-58 years). Twenty-four percent of the patients had suffered severe injuries (Injury Severity Score [ISS], 16-25), 17% very severe injuries (ISS > 25), 24% moderately severe injuries, and 36% minor injuries (ISS, 1-8). The overall geographical distribution was centroidal, although with a concentration of case volume in the vicinity, and to the northeast, of the trauma center. Median flight time was 60 minutes (IQR, 52-69 minutes), and median drive time 65 minutes (IQR, 54-86 minutes). In 33% of the patients, the calculated drive time to the trauma center was shorter than the calculated flight time when considering the time for the helicopter to reach the scene. CONCLUSION: The majority of patients taken to our level I trauma center by helicopter are injured in relatively close proximity. One in four patients is severely or very severely injured, but one third of the patients have only minor injuries. Over a quarter of trauma patients might have reached hospital more quickly if they had been taken by road, rather than helicopter. LEVEL OF EVIDENCE: Epidemiological/geographical study, level V.