Out-of-hospital decision making and factors influencing the regional distribution of injured patients in a trauma system.

BACKGROUND: The decision-making processes used for out-of-hospital trauma triage and hospital selection in regionalized trauma systems remain poorly understood. The objective of this study was to assess the process of field triage decision making in an established trauma system.
METHODS: We used a mixed methods approach, including emergency medical services (EMS) records to quantify triage decisions and reasons for hospital selection in a population-based, injury cohort (2006-2008), plus a focused ethnography to understand EMS cognitive reasoning in making triage decisions. The study included 10 EMS agencies providing service to a four-county regional trauma system with three trauma centers and 13 nontrauma hospitals. For qualitative analyses, we conducted field observation and interviews with 35 EMS field providers and a round table discussion with 40 EMS management personnel to generate an empirical model of out-of-hospital decision making in trauma triage.
RESULTS: A total of 64,190 injured patients were evaluated by EMS, of whom 56,444 (88.0%) were transported to acute care hospitals and 9,637 (17.1% of transports) were field trauma activations. For nontrauma activations, patient/family preference and proximity accounted for 78% of destination decisions. EMS provider judgment was cited in 36% of field trauma activations and was the sole criterion in 23% of trauma patients. The empirical model demonstrated that trauma triage is driven primarily by EMS provider "gut feeling" (judgment) and relies heavily on provider experience, mechanism of injury, and early visual cues at the scene.
CONCLUSIONS: Provider cognitive reasoning for field trauma triage is more heuristic than algorithmic and driven primarily by provider judgment, rather than specific triage criteria.