In the United States:

• Trauma is the leading cause of death for individuals up to the age of 40 years.
• Trauma is the fourth leading cause of death overall for all ages.
• There are almost 40,000 homicide and suicide deaths each year in the US.

Mechanism of Injury

The mechanism of injury is the earliest component of the Primary Survey. It assists you in establishing both the safety of the scene and guides the remainder of the primary survey. The seriousness of the mechanism of injury is a significant clue as to the potential seriousness of the patient's actual injuries, be they external or internal.

Relaying the mechanism of injury to downstream care providers early in the course of transport helps them be better prepared and have the necessary resources available for when they are treating the patient in the near future. A patient with a severe mechanism of injury (MOI) warns providers that they may have a patient who requires many hands/tools/teams for treatment. Getting those people alerted and organized is a great head start for your patient.

MOIs can be divided into two broad categories,

1. significant and
2. insignificant.

The division between these groups is nothing more than the likelihood that a patient with a certain MOI will present with trauma requiring intensive care. Not all patients with an insignificant MOI are free from severe injuries and vice versa!

SIGNIFICANT INJURIES: Some examples of significant mechanisms of injury are:

• Ejection from a vehicle.
• Prolonged extrication time.
• Multi-system trauma.
• Motor vehicle-pedestrian/biker accidents.
• Motor vehicle accidents where any occupant of the vehicle was killed.
• Any fall over 3 times the patient's height.

INSIGNIFICANT INJURIES: Some common insignificant mechanisms of injury are:

• Fights or physical altercations without loss of consciousness.
• Minor injuries to isolated body parts.
• Car accidents without injury or symptoms of injury to any occupant.

Mechanism of injury should be re-evaluated after go/no-go decision for transport is made. Decisions at the initiation of an encounter can be prone to error due to chaos on the scene and adrenaline.

SPINAL PRECAUTIONS: Keep in mind the potential need for spinal precautions in patients with significant mechanisms of injury.

Many MOIs that are deemed significant can present with injury to multiple bodily symptoms. These patients will often have physical symptoms and patient complaints that lead to suspicions of a spinal injury otherwise masked.

Be sure to review this resource regarding field triage guidelines - ***This is NOT for mass casualty triage, but for individual patient injuries***: Field Triage Guidelines