The 60 minutes after a traumatic injury is sometimes referred to as the “golden hour,” a window of time in which a victim is thought to have the greatest chance of survival if given medical attention. Though this idea has become conventional wisdom, rushing to arrive within the window carries risk — speeding EMS vehicles aren’t immune from accidents, after all — and the exact relationship between response times and the survival odds has not been definitively established.

A 2009 study published in the Annals of Emergency Medicine, “Emergency Medical Services Intervals and Survival in Trauma: Assessment of the ‘Golden Hour’ in a North American Prospective Cohort,” analyzed a patient registry of 3,656 adult trauma victims transported by 146 EMS agencies to 51 hospitals between 2005 and 2007. Patients were chosen based on a uniform set of health criteria: blood pressure reading, respiratory rate and Glasgow Coma Scale score. Of the 3,656 subjects studied, 806 died as a result of the incident that prompted the emergency response.

Major points made in the study include:

• Though response times varied across the places studied, the median amount of time from the 911 call to arrival at the hospital was 36.3 minutes. That included a high of 42 minutes in Seattle and a low of 28 minutes in Iowa.
• Total EMS time was not linked to mortality rates, even when broken down into subgroups (for example, examining results specifically for children or for those whose treatment took place after 60 minutes.)
• The only cases in which response time has proven to matter statistically are those relating to non-traumatic cardiac arrest. (The authors of this study do not dispute that finding with their data.)

The authors note that previous studies have reached opposite conclusions, and much EMS policy continues to focus on response speed. However, this study’s findings do not support the idea that promptness prevents deaths. The authors hypothesize that the “golden hour” idea may well be dependent on timely treatment at the hospital itself, adding that “such a possibility would lend credence to a ‘golden hour’ concept and be consistent with the previously demonstrated hospital-based effect on survival.”

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