Background: Prehospital emergency medical services (EMS) play a major
role in any trauma system. However, there is very little information r
egarding the role of prehospital emergency care in trauma. To investig
ate this issue, eve compared the outcome of severely injured patients
transported by paramedics (EMS group) with the outcome of those transp
orted by friends, relatives, bystanders, or police (non-EMS group). De
sign: We compared 4856 EMS patients with 926 non-EMS patients. General
linear model analysis was performed to test the hypothesis that hospi
tal mortality is the same in EMS and non-EMS cases, controlling for th
e following confounding factors, which are not affected by mode of tra
nsportation: age, gender, mechanism of injury, cause of injury, Injury
Severity Score (ISS), and severe head injury. Crude, specific, and ad
justed mortality rates and relative risks were also derived for the EM
S and non-EMS groups. Setting: Large, urban, academic level I trauma c
enter. Patients: All patients meeting the criteria for major trauma. R
esults: The two groups were similar with regard to mechanism of injury
and the need for surgery or intensive care unit admission. The crude
mortality rate was 9.3% in the EMS group and 4.0% in the non-EMS group
(relative risk, 2.32; P<.001). After adjustment for ISS, the relative
risk was 1.60 (P=.002). Subgroup analysis showed that among patients
with ISS greater than 15, those in the EMS group had a mortality rate
twice that of those in the non-EMS group (28.8% vs 14.1%). After contr
olling for confounding factors, the adjusted mortality among patients
with ISS greater than 15 was 28.2% for the EMS group and 17.9% for the
non-EMS group (P<.001). Conclusions: Patients with severe trauma tran
sported by private means in this setting have better survival than tho
se transported via the EMS system. Large prospective studies are neede
d to identify the factors responsible for this difference.