Validation of a prehospital trauma triage tool: a 10-year perspective

Triage of the trauma patient in the field is a complex and challenging issue, especially deciding when to use aeromedical transport. The American College of Surgeons Committee on Trauma recently defined an acceptable under-triage rate [seriously injured patient not taken to a trauma center (TC)] as 5%, whereas over-triage rates may be as high as 25% to 50%. Effective utilization of prehospital helicopter transport requires both accurate assessment of patients and effective communication. The rural county adjacent to our developed trauma system uses standardized triage criteria to identify patients for direct transport to our TCs. We hypothesized these criteria accurately identify major trauma victims (MTV) and further that communication could be simplified to expedite transport.

Prehospital personnel use a MAP (mechanism, anatomy, and physiology) scoring system to triage trauma patients. Patients with > or = 2 "hits" are defined as MTV. In 2004, the triage policy was changed so that MTV would be transported directly to a TC without base hospital consultation (previously required). The Emergency Medical Services (EMS) Medical Director reviewed cases transported to the TC to determine the appropriateness of triage decisions (over- and under-triage using the American College of Surgeons Committee on Trauma definitions). Data were compared before and after this policy change.

For 2004 to 2006, we evaluated 676 air transports to TC and compared them to 468 in the prior 56 months. The overall transport rate increased slightly 7% to 10%. During the study period the over-triage rate was 31% compared with 21%, before the policy change. The MAP triage tool yielded a 93.8% sensitivity and a 99.5% specificity. Therefore, it determined the need for air-medical transport out of a rural environment into an established trauma system with > 90% accuracy.

Prehospital personnel can accurately use a trauma triage tool to identify MTV. Eliminating base station contact, a potential for introducing communication error, did increase over-triage but still well within accepted limits. The system change also resulted in the transport of a greater proportion of minor trauma patients who later proved to have major injuries.