Intentional mass casualty events: Implications for prehospital emergency medical services systems.

Domestic and international events of mass violence, including active shooter and intentional mass casualty incidents, warrant unique response considerations for prehospital emergency medical services (EMS) and first responder agencies. Regardless of whether an EMS system serves an urban, suburban, or rural community, and independent of the EMS system’s architecture, these events represent a complex and challenging interagency response scenario for which all EMS agencies must be prepared. These events have resulted in multiple casualties with both blunt and penetrating injury patterns. For any critically ill or injured patient, survival is often dependent on prompt and immediate access to lifesaving interventions. The principal concept of THREAT (Threat suppression, Hemorrhage control, Rapid Extrication to safety, Assessment by medical providers, and Transport to definitive care), as outlined in the Hartford Consensus documents, provides an organized and systematic approach to the priorities of responding emergency personnel. Specifically, the notion of hemorrhage control represents a fundamental tenet of responder capability for both lay and professional rescuers, as well as for EMS system readiness. Past experience has demonstrated that those casualties with mild injuries tend to self-evacuate. These prior events also have demonstrated that civilian immediate responders will often render aid to more seriously injured victims. The role of immediate responders in providing immediate hemorrhage control cannot be underestimated and is a vital link in the chain of survival for victims. Beyond theory, the tenets behind THREAT have been proven both on the battlefield and in the wake of some of the worse recent domestic attacks in the U.S. This concept aligns naturally with recommendations and guidelines of other allied groups, including the U.S. military’s Committee on Tactical Combat Casualty Care1 and the civilian Committee for Tactical Emergency Casualty Care.2 Both groups emphasize the importance of early hemorrhage control, in addition to the ability to address immediately correctible causes of death, including tension pneumothorax and airway obstruction. The work of these groups has helped shape national-level policy and guidance documents, most recently including the U.S. Department of Homeland Security’s June 2015 First Responder Guide for Improving Survivability in Improvised Explosive Device and/or Active Shooter Incidents.3 This evidence-based document calls for a realignment of traditional emergency services practices to improve victim survivability and responder safety. It focuses on three specific areas: hemorrhage control, protective equipment, and response/incident management.