Association Between Mode of Transportation and Outcomes of Adult Trauma Patients With Blunt Injury Across Different Prehospital Time Intervals in the United States: A Matched Cohort Study

Abstract

Helicopter Emergency Medical Services (HEMS) dispatch currently depends on predefined protocols, on first responders' initial assessment, or on medical direction decision in some states. National guidelines do not provide recommendations concerning prehospital time criteria. Our aim was to investigate the association between the mode of transportation (HEMS vs. ground EMS [GEMS]) and survival of adult patients with blunt trauma across different prehospital time intervals. This retrospective matched cohort study was carried out using the 2015 National Trauma Data Bank (NTDB) dataset. Adult patients with blunt injuries transported via HEMS were selected and matched (1 to 1) for 13 variables to those who were transported by GEMS. Survival rates were calculated for the two groups across different prehospital time intervals. Patients transported by HEMS (n=16,269) were compared with those transported by GEMS (n=16,269). Most patients were aged 16 to 64years (84.0%), male (69.4%), and white (88.0%). Overall survival rate to hospital discharge was significantly higher in the HEMS group (96.8% vs. 96.2%; p=0.002). Patients transported by HEMS had higher survival rates in the ≤ 30-min interval (97.7% vs. 93.2%; p=0.004); GEMS patients had higher survival rates in the 61- to 90-min interval (97.4% vs. 96.5%; p=0.038). No difference in survival rates between the two groups was observed in intervals > 90min. In adult patients with blunt trauma, HEMS transport was associated with overall improved survival rates mainly in the first 30min after injury. GEMS transport, however, had a survival advantage in the 61- to 90-min total prehospital time interval.