Objective: To compare the sensitivity of current field triage practices for identifying high-risk trauma patients to strict guideline adherence, including changes in triage specificity, ambulance transport patterns, and trauma center volumes.
Methods: This was a pre-planned secondary analysis of an out-of-hospital prospective cohort of injured children and adults transported by 44 EMS agencies to 28 trauma and non-trauma hospitals in 7 Northwest U.S. counties from January 1, 2011 through December 31, 2011. Outcomes included Injury Severity Score (ISS) ≥16 (primary) and early critical resource use. Strict adherence of the triage guidelines was based on evidence in the EMS chart for patients meeting any current field triage criteria, calculated with and without strict interpretation of the age criterion (<15 or >55 years). Due to the probability sampling nature of the cohort, strata and weights were included in all analyses.
Results: 17,633 injured patients were transported by EMS (weighted to represent 53,487 transported patients), including 3.1% with ISS ≥16 and 1.7% requiring early critical resources. Field triage sensitivity for identifying patients with ISS ≥16 increased from the current 66.2% (95% CI 60.2-71.7%) to 87.3% (95% CI 81.9-91.2%) for strict adherence without age and to 91.0% (95% CI 86.4-94.2%) for strict adherence with age. Specificity decreased with increasing adherence, from 87.8% (current) to 47.6% (strict adherence without age) and 35.8% (strict adherence with age). Areas under the curve (AUC) were 0.78, 0.73, and 0.72, respectively. Results were similar for patients requiring early critical resources. We estimate the number of triage-positive patients transported each year by EMS to an individual major trauma center (on average) to increase from 1,331 (current) to 5,139 (strict adherence without age) and to 6,256 (strict adherence with age).
Conclusions: The low sensitivity of current triage practices would be expected to improve with strict adherence to current triage guidelines, with a commensurate decrease in triage specificity and an increase in the number of triage-positive patients transported to major trauma centers.
Keywords: adherence; emergency medical services; trauma; triage.