Shootings: What EMS Providers Need to Know

The assessment and treatment of victims of gunshot wounds


   Firearm-related injuries continue to be a significant public health problem, accounting for almost 20% of injury-related deaths in the United States.1

   From January 1993 to December 1998, an estimated 115,000 firearm-related injuries occurred annually in the U.S. Males were seven times more likely to die or be treated in emergency departments for gunshot wounds than females. In 2006 more than 30,000 persons died from firearm injuries in the United States.2

   Gunshot wounds to the head are the most lethal of all firearm injuries.3 It is estimated they have a fatality rate greater than 90%. Those to the myocardium have fatality rates reaching 80%. Intra-abdominal injuries from gunshot wounds tend to involve the small bowel (50%), colon (40%), liver (30%) and abdominal vascular structures (25%).4

PENETRATING MOI

   Gunshot wounds involve the transfer of energy to a target. The damage that occurs is directly related to the amount of energy exchanged between the penetrating object and what it strikes, which relates to the projectile's mass and velocity. Other influencing factors include tissue density, the penetrating object's frontal area, and the distance between the weapon and the target.5–9

   When a bullet strikes a person, tissue is crushed. The bullet's forward movement creates a temporary tunnel that expands to a larger tunnel. The larger tunnel is considered to be a temporary "cavitation" wave. Tissues in the temporary cavity sustain damage from compression, deformation and shear. After a bullet passes through, the temporary cavity recoils to its normal position, but with a remaining cavitation, called the permanent cavity. Tissue of the permanent cavity may be damaged and nonviable. Secondary missiles, such as bullet and bone fragments, can result in additional damage.5–9

   Penetrating mechanisms of injury can be described as low, medium or high velocity. Damage from low-velocity mechanisms, such as stabbings, is often limited to the structures directly contacted. Medium-velocity mechanisms, like bullets from most types of handguns, produce less tissue destruction than high-velocity forces. High-velocity mechanisms include shots from rifles and larger military weapons.5–9

   Bullet design varies. Some are encased with hard "jackets," typically copper, to prevent the lead inside from deforming against a target. This promotes deeper penetration. Bullets that deform or fragment, such as those with soft or hollow points, may ricochet inside the body. Factors that can influence this include the location of the bullet's entry and the distance between the weapon and the victim when the weapon was fired.5–9

   Shotguns have shells containing small spherical pellets (shot) or items such as slugs or flechettes. These contents spread apart as they leave the barrel, distributing the blast energy over a wider area. At close range shotgun injuries can be more severe than bullet injuries. At greater range, the wider spread and lower velocity of the pellets tend to produce separated and superficial injuries.7

ENTRY, EXIT

   Gunshots may create both entrance and exit wounds. Entrance wounds tend to have a round shape with a surrounding margin of abrasion. Contact wounds occur when a firearm is held directly against the body, and can include a muzzle imprint and soot on the skin. Close- or intermediate-range wounds may have a wider zone of powder stippling. Distant-range wounds tend to lack powder stippling and may have holes roughly equal to the caliber of the projectile fired.8,9

   Exit wounds can have a variety of appearances, including round, oval, slitlike, stellate or crescent. They may be larger than entrance wounds if the bullet expanded or tumbled on its axis, but most likely won't have gunshot residue. If an exit wound was abutted by firm support, such as clothing or furniture, it may have a circular defect and abraded margin resembling an entrance wound.8,9

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