Emergency medical services out-of-hospital scene and transport times and their association with mortality in trauma patients presenting to an urban Level I trauma center

Abstract

Study objective: We determine the association between emergency medical services (EMS) out-of-hospital times and mortality in trauma patients presenting to an urban Level I trauma center.

Methods: We conducted a secondary analysis of a prospective cohort registry of trauma patients presenting to a Level I trauma center during a 14-year period (1996 to 2009). Inclusion criteria were patients sustaining traumatic injury who presented to an urban Level I trauma center. Exclusion criteria were extrication, missing or erroneous out-of-hospital times, and intervals exceeding 5 hours. The primary outcome was inhospital mortality. EMS out-of-hospital intervals (scene time and transport time) were evaluated with multivariate logistic regression.

Results: There were 19,167 trauma patients available for analysis, with 865 (4.5%) deaths; 16,170 (84%) injuries were blunt, with 596 (3.7%) deaths, and 2,997 (16%) were penetrating, with 269 (9%) deaths. Mean age and sex for blunt and penetrating trauma were 34.5 years (68% men) and 28.1 years (90% men), respectively. Of those with Injury Severity Score less than or equal to 15, 0.4% died, and 26.1% of those with a score greater than 15 died. We analyzed the relationship of scene time and transport time with mortality among patients with Injury Severity Score greater than 15, controlling for age, sex, Injury Severity Score, and Revised Trauma Score. On multivariate regression of patients with penetrating trauma, we observed that a scene time greater than 20 minutes was associated with higher odds of mortality than scene time less than 10 minutes (odds ratio [OR] 2.90; 95% confidence interval [CI] 1.09 to 7.74). Scene time of 10 to 19 minutes was not significantly associated with mortality (OR 1.19; 95% CI 0.66 to 2.16). Longer transport times were likewise not associated with increased odds of mortality in penetrating trauma cases; OR for transport time greater than or equal to 20 minutes was 0.40 (95% CI 0.14 to 1.19), and OR for transport time 10 to 19 minutes was 0.64 (95% CI 0.35 to 1.15). For patients with blunt trauma, we did not observe any association between scene or transport times and increased odds of mortality.

Conclusion: In this analysis of patients presenting to an urban Level I trauma center during a 14-year period, we observed increased odds of mortality among patients with penetrating trauma if scene time was greater than 20 minutes. We did not observe associations between increased odds of mortality and out-of-hospital times in blunt trauma victims. These findings should be validated in an external data set.