Characteristics and outcomes of injured patients presenting by private vehicle in a state trauma system.

BACKGROUND: Previous studies have demonstrated lower mortality among patients transported to single urban trauma centers by private vehicle (PV) compared with Emergency Medical Services (EMS). We sought to describe the characteristics and outcomes of injured patients transported by PV in a state trauma system compared to patients transported by EMS.
METHODS: We performed a retrospective cohort study of state trauma registry data for patients admitted to all Pennsylvania trauma centers over 5 years (1/2003 to 12/2007). Our primary exposure of interest was prehospital mode of transport and our primary outcome of interest was in-hospital mortality. Unadjusted analyses were performed as were adjusted analyses controlling for injury severity. Data are presented as percents, odds ratios (ORs), and 95% confidence intervals.
RESULTS: Of the 91132 patients analyzed, 9.6% were transported to the emergency department by PV and 90.4% by EMS. Overall Injury Severity Score (ISS) was 13.3 ± 11.0 (ISS for EMS 13.7 ± 11.3, PV 9.2 ± 7.1, P < .001), and 6.6% of patients died (EMS 7.1%, PV 1.5%, P < .001). After adjusting for injury severity, patients transported by EMS were more likely to die than PV patients (OR 1.9 [95% CI 1.5-2.4]). This effect persisted in blunt, penetrating, advanced life support, and basic life support subgroups, but not in the severely injured (ISS >15, ISS >25) subgroups.
CONCLUSIONS: Nearly 10% of injured patients arrive at trauma centers by private vehicle. Transport of injured patients by EMS was associated with higher mortality than PV transport. This may reflect the effects of prehospital time, prehospital interventions, or other confounders.