Emergency medical services/original research
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

Presented as an abstract at the American College of Emergency Physicians 2010 Scientific Assembly, September 2010, Las Vegas, NV.
https://doi.org/10.1016/j.annemergmed.2012.08.026Get rights and content

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.

Introduction

Debate continues over the “load and go” versus “stay and stabilize” approach to patient care in the out-of-hospital setting because there is a paucity of supportive data for either argument. The critical factor at the center of this debate is emergency medical services (EMS) out-of-hospital time (response time, scene time, and transport time) and its association with patient outcome, namely, morbidity and mortality. Although the optimal out-of-hospital intervals for EMS personnel have not been defined for major trauma, it has been recommended that the least amount of time required in the out-of-hospital setting be spent, allowing only for performance of essential procedures.1, 2, 3

Multiple elements compose an EMS system, each with inherent qualities that may be reviewed, analyzed, and improved on if deficient.4 One component currently in debate and commonly scrutinized by administrators, elected officials, and the public, and one potentially affecting patient care, is the association between out-of-hospital time and mortality in patients presenting to a trauma center.

In the United States, trauma is the fifth leading cause of death, claiming more than 121,500 lives annually.5, 6 Unintentional injury is the leading cause of death for people between the ages of 1 and 44 years and is responsible for more years of life lost than stroke, cancer, and cardiovascular disease combined.6, 7 Given these facts and statistics, identifying factors associated with trauma-related mortality is a critical step in the process of medical systems evaluation and improvement.

Although many factors may contribute to mortality in the acutely injured trauma patient, identifying those factors that are associated with mortality that have the potential to be systematically improved on within the EMS structure could have tremendous implications for patient care and outcome. This study is designed to identify the association between out-of-hospital time and mortality in trauma patients presenting to an urban Level I trauma center. This information may provide factors that can be improved on at the systems level to affect change (decrease mortality) at the population level.

Section snippets

Study Design

We conducted a secondary analysis of a prospective cohort registry of trauma patients presenting to an urban Level I trauma center during a 14-year period (January 1996 to December 2009).

Study Setting and Selection of Participants

This study was conducted in Orange County, CA, which is composed of 34 cities within approximately 800 square miles and is bordered by Los Angeles County to the northwest, San Bernardino County to the northeast, Riverside County to the east, San Diego County to the southeast, and the Pacific Ocean to the

Characteristics of Study Subjects

Continuous data were obtained for all patients presenting to the study facility during a 14-year period (January 1996 to December 2009). Twenty-six thousand five hundred sixty-four cases were eligible for review. Excluded cases consisted of 1,515 for extrication, 4,805 missing 1 or more time data items (scene or transport times), 334 with scene or transport time less then zero minutes or greater than 300 minutes, 2 missing final outcome data (ie, mortality report), 418 not listed as “blunt” or

Limitations

Previous studies have shown an association between increased out-of-hospital times and decreased mortality, as well as an association between increasing Injury Severity Score and decreased scene and transport times.3, 12, 13, 14, 15, 16, 17 The association between increased out-of-hospital times and decreased mortality may be in part explained by EMS providers moving with haste for patients thought to have serious injury and taking more time for patients recognized as having minor injuries. The

Discussion

In this secondary analysis of a prospective cohort registry of trauma patients presenting to a Level I trauma center during a 14-year period, we observed an association between longer out-of-hospital times, in particular scene times, and mortality in patients with penetrating trauma and an Injury Severity Score greater than 15. This study is the first to our knowledge to analyze data spanning more than a decade, including close to 20,000 patients, with specific aims to evaluate the association

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  • Cited by (0)

    Supervising editor: Theodore R. Delbridge, MD, MPH

    Author contributions: CEM and CK were responsible for synthesizing research questions and overseeing the study. CEM and SS were responsible for researching current literature. CEM was responsible for developing a method for testing the research questions. CEM, CK, and MM were responsible for analyzing the data. CEM and MM were responsible for interpreting the data. CEM, MM, and SS were responsible for writing the article. CK and MM were responsible for editing the article. CA was responsible for statistical analysis. CEM takes responsibility for the paper as a whole.

    Funding and support: By Annals policy, all authors are required to disclose any and all commercial, financial, and other relationships in any way related to the subject of this article as per ICMJE conflict of interest guidelines (see www.icmje.org). The authors have stated that no such relationships exist.

    Please see page 168 for the Editor's Capsule Summary of this article.

    Dr Menchine is currently affiliated with USC Keck School of Medicine, Los Angeles, CA.

    Publication date: Available online November 9, 2012.

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