In the Field
MOI is what tells you to look harder for the injury that is not obvious. A high-velocity gunshot wound to the chest is going to do more than the entry and exit holes show. A casualty thrown 20 feet by an IED blast has overpressure injury to the lungs, ears, and abdomen even when the external wounds look minor. A motorcycle crash at highway speed produces solid organ injury, pelvic fracture, and TBI in proportion to the energy involved. Documenting MOI on the DD 1380 lets receiving providers know what to evaluate for.
Common Mistake
Treating the visible injury and stopping. A casualty with an obvious extremity wound from blast injury who is not assessed for blast lung, tympanic rupture, or intra-abdominal solid organ injury may deteriorate later from injuries that were predictable from the mechanism. The other mistake is failing to document MOI with sufficient specificity. IED blast is less useful than IED blast with casualty within 5 meters of detonation, vehicle compromised, casualty thrown approximately 3 meters. Receiving providers can do something with the second description; the first leaves them guessing.
Technical Detail
MOI categories: blunt (motor vehicle crash, falls, blast secondary, sports); penetrating (gunshot wound, stab wound, fragment injury, primary blast penetrating); thermal (burns, frostbite); chemical (acid or alkali, vesicants); electrical (high voltage, low voltage, lightning); blast (primary equals overpressure injury to gas-containing organs, secondary equals fragment injury, tertiary equals displacement injury, quaternary equals thermal, asphyxia, exacerbation of underlying disease). Energy transfer in penetrating trauma is approximated by kinetic energy equation (KE equals one-half mass times velocity squared); high-velocity projectiles transfer dramatically more energy than low-velocity. Common predictable injury patterns: high-velocity GSW chest produces both entry/exit and cavitation injury along the wound tract; falls from height greater than 20 feet have high incidence of TBI, spinal injury, and solid organ injury.
