Emergency Medical Services Intervals and Survival in Trauma: Assessment of the “Golden Hour” in a North American Prospective Cohort

Presented as an abstract at the Society for Academic Emergency Medicine Annual Meeting, May 2008, Washington, DC.

Received 13 March 2009; received in revised form 19 June 2009; accepted 22 July 2009. published online 24 September 2009.
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Study objective

The first hour after the onset of out-of-hospital traumatic injury is referred to as the “golden hour,” yet the relationship between time and outcome remains unclear. We evaluate the association between emergency medical services (EMS) intervals and mortality among trauma patients with field-based physiologic abnormality.

Methods

This was a secondary analysis of an out-of-hospital, prospective cohort registry of adult (aged ≥15 years) trauma patients transported by 146 EMS agencies to 51 Level I and II trauma hospitals in 10 sites across North America from December 1, 2005, through March 31, 2007. Inclusion criteria were systolic blood pressure less than or equal to 90 mm Hg, respiratory rate less than 10 or greater than 29 breaths/min, Glasgow Coma Scale score less than or equal to 12, or advanced airway intervention. The outcome was inhospital mortality. We evaluated EMS intervals (activation, response, on-scene, transport, and total time) with logistic regression and 2-step instrumental variable models, adjusted for field-based confounders.

Results

There were 3,656 trauma patients available for analysis, of whom 806 (22.0%) died. In multivariable analyses, there was no significant association between time and mortality for any EMS interval: activation (odds ratio [OR] 1.00; 95% confidence interval [CI] 0.95 to 1.05), response (OR 1.00; 95% CI 9.97 to 1.04), on-scene (OR 1.00; 95% CI 0.99 to 1.01), transport (OR 1.00; 95% CI 0.98 to 1.01), or total EMS time (OR 1.00; 95% CI 0.99 to 1.01). Subgroup and instrumental variable analyses did not qualitatively change these findings.

Conclusion

In this North American sample, there was no association between EMS intervals and mortality among injured patients with physiologic abnormality in the field.

a Center for Policy and Research in Emergency Medicine, Department of Emergency Medicine, Oregon Health & Science University, Portland, OR

b Department of Biostatistics, University of Washington, Seattle, WA

c Department of Surgery, University of Washington, Seattle, WA

d University of Washington Clinical Trial Center, University of Washington–Harborview Center for Prehospital Emergency Care, University of Washington, Seattle, WA

e Department of Medicine, John A. Burns School of Medicine, University of Hawaii–Manoa, Honolulu, HI

f Department of Emergency Medicine, University of Ottawa, Ottawa, Ontario, Canada

g Department of Surgery, University of Ottawa, Ottawa, Ontario, Canada

h Department of Emergency Medicine, University of California at San Diego, San Diego, CA

i Department of Emergency Medicine, Medical College of Wisconsin, Milwaukee, WI

j Department of Surgery, University of Texas Southwestern Medical Center, Dallas, TX

k Department of Anesthesia, Division of Critical Care, University of Iowa, Iowa City, IA

l Legacy Emanuel Trauma Program, Portland, OR

m Department of Emergency Medicine, University of Alabama at Birmingham, Birmingham, AL

Address for correspondence: Craig D. Newgard, MD, MPH, Department of Emergency Medicine, Center for Policy and Research in Emergency Medicine, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Mail Code CR-114, Portland, OR 97239-3098; 503-494-1668, fax 503-494-4640

Reprints not available from the authors.

Supervising editor: Daniel W. Spaite, MD

Author contributions: CDN conceived of and designed the study. RS performed the database management, quality assurance of the data, and all statistical analyses. CDN, RS, JRH, JPT, DPD, EMB, and GN interpreted preliminary findings and assisted in refining the final analysis. CDN drafted the article, and all authors contributed substantially to its revision. RS takes responsibility for data quality and all analyses. CDN 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 that might create any potential conflict of interest. See the Manuscript Submission Agreement in this issue for examples of specific conflicts covered by this statement. The Resuscitation Outcome Consortium was supported by a series of cooperative agreements to 10 regional clinical centers and 1 data coordinating center (5U01 HL077863, HL077881, HL077871, HL077872, HL077866, HL077908, HL077867, HL077885, HL077877, HL077873) from the National Heart, Lung, and Blood Institute, in partnership with the National Institute of Neurological Disorders and Stroke, US Army Medical Research and Material Command, the Canadian Institutes of Health Research-Institute of Circulatory and Respiratory Health, Defence Research and Development Canada, the Heart and Stroke Foundation of Canada, and the American Heart Association.

PII: S0196-0644(09)01284-0

doi:10.1016/j.annemergmed.2009.07.024