Helicopter emergency medical services (HEMS) offers rapid transport to trauma centers while simultaneously providing advanced prehospital care. It is through these reasons that HEMS carries a survival benefit over ground emergency medical services (GEMS). However, increasing financial burdens and aviation risks to flight crews/patients complicate the decision to transport a patient by HEMS. Determining which patients should be transported by HEMS is not uniform among trauma centers and often pulls existing trauma triage criteria and applies to to air transport triage. This post intoduces the external validation of the Air Medical Prehospital Triage score which was developed to identify patients most likely to benefit from scene HEMS transport:

Brown et al. "External Validation of the Air Medical Prehospital Triage Score for Identifying Trauma Patients Likely to Benefit from Scene Helicopter Transport." Journal of Trauma and Acute Care Surgery. February 2017, p 270-279.

Air Medical Prehospital Triage (AMPT) Score:

• GCS < 14 - 1 point
• Respiratory Rate <10 or >29 breaths/minute - 1 point
• Unstable chest wall fractures - 1 point
• Suspected hemothorax of pneumothorax - 1 point
• Paralysis - 1 point
• Multisystem trauma (>2 body regions injured) - 1 point
• Any physiologic + any anatomic criterion from National Field Triage Guidelines - 2 points
• Consider helicopter transport if AMPT score is greater than or equal to 2 points

Study Design:

• Retrospective external validation of AMPT score using Pennsylvania Trama Outcomes Study registry of 222,827 patients over 14 years. 
• Patients with an AMPT score of 2 or greater were "triaged" to HEMS

Results:

• For patients with an AMPT score <2 and "triaged" to GEMS, either mode of transportation provided no survival benefit.
• For patients "triaged" to HEMS by an AMPT score of 2 or greater there was an 6.7% increased in realtive probaility of survival (ARR 1.067, 95% CI 1.04-1.083, p=<0.001)

Conclusions:

• The AMPT score of 2 or greater performs well when discriminating between patients who will have a survival benefit if transported by HEMS
• AMPT is a simple score that can be applied easily at the scene.
• AMPT should not be used in isolation and does not factor in distance, traffic patters, weather, availability, resources.