Emergency medical services intervals and survival in trauma: assessment of the "golden hour" in a North American prospective cohort.
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 > or =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 in-hospital 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.


CONCLUSIONS
In this North American sample, there was no association between EMS intervals and mortality among injured patients with physiologic abnormality in the field.
Newgard
Craig D
CD
Center for Policy and Research in Emergency Medicine, Department of Emergency Medicine, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239-3098, USA. newgardc@ohsu.edu
Schmicker
Robert H
RH
Hedges
Jerris R
JR
Trickett
John P
JP
Davis
Daniel P
DP
Bulger
Eileen M
EM
Aufderheide
Tom P
TP
Minei
Joseph P
JP
Hata
J Steven
JS
Gubler
K Dean
KD
Brown
Todd B
TB
Yelle
Jean-Denis
JD
Bardarson
Berit
B
Nichol
Graham
G
D000328:Adult; D015331:Cohort Studies; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009656:North America; D011446:Prospective Studies; D013997:Time Factors; D014187:Transportation of Patients; D014193:Trauma Centers / Q000706:statistics & numerical data*; D016896:Treatment Outcome; D014947:Wounds and Injuries / Q000401:mortality* / Q000628:therapy; D055815:Young Adult