Police officers, fire fighters, and other first responders encounter more and more gunshot wounds. Knowing how to diagnose and treat such wounds, at least until delivering the victims to definitive care, is critical.

By Mark D. Harris

The Second Amendment, communicating the right to bear arms, is sacrosanct in American culture. Patriots for centuries have seen it as a defense against tyranny. Americans have a larger number of guns per capita than most other developed nations. However important having all those guns is in neutralizing bad guys, the ubiquity of firearms in the US results in larger numbers of suicides, accidental gunshot wounds, and homicides.

History

Treatment prior to the 1880s involved the doctor sticking his fingers into the wound to try to grab and remove the projectile. US President James Garfield (1831-1881) died in September 1881 after being shot in July 1881. He probably would have survived the wound had doctors not repeatedly probed the wound with dirty fingers and dirty instruments.

Providentially, in July 1881, George E. Goodfellow (1855-1910) performed the first successful open abdominal surgery for a gunshot wound in Tombstone AZ. He used sterile technique and his patient recovered. Alexander Graham Bell (1847-1922) invented the Induction Balance which found bullets in Civil War soldiers. Radiographs followed as an even better way to find projectiles and other foreign bodies through skin.

Remarkable advances in medicine and protection (like body armor) through the world wars and into the modern era have made GSWs more survivable, but advances in weapons technology have also made them deadlier. Nonetheless, people who survive the initial injury are more likely than ever to survive long term.

Epidemiology

In 2023, 45% of American households owned one or more firearms.[1] Simultaneously, firearms accounted for 14789 of 17830 (82.9%) murders in the US in 2022. The firearm industry has grown, jumping from $19.1 billion in 2008 to $70.52 billion in 2021.[2] People employed by the industry increased from 166,000 to 375,819 over the same interval. Guns are used defensively between 500,000 and 3,000,000 times per year, but these instances are rarely reported by the media.[3] Often, incidents are not reported to law enforcement either. Firearms considered “assault rifles” like the AR-15 and handguns are commonly used in self-defense.    

Modern Firearms

Modern firearms include the following types of weapons. Rifles are primarily used for military and outdoors (such as hunting) applications. Handguns are primarily seen in shooting sports, law enforcement, and personal defense. Historical reenactors use period muskets (such as the Brown Bess of the American Revolution) for enjoyment and education. Shotguns excel at bird hunting, in which the spread is useful for bringing down birds on the wing. Shotguns are also commonly used in law enforcement and personal defense.  

Table 1[4] – Key characteristics

	Handguns	Muskets	Rifles	Shotguns
Rifling – spiral grooves in the barrel to make the projectile spin, thus improving accuracy[5]	X		X
Breech loading – as opposed to loading from the tip of the barrel[6]	X		X	X
Muzzle velocity – higher in weapons with longer barrels since the expanding gases push longer on the projectile[7]	400 m/s	300 m/s	1200 m/s	400 m/s
Hands needed to control	1	2	2	2

Physics of Flight

Like any object moving through fluid, projectiles from firearms flying are subject to three axes of motion around their center of gravity. The first is yaw, the tendency to move horizontally (side to side). The second is pitch, the tendency to move up and down. The third is roll, the tendency to rotate around the projectiles’ midline. Flying objects are also influenced by thrust, the propulsive force, which is counteracted by drag. In a firearm, thrust continuously diminishes after the projectile leaves the barrel. The last force, gravity, brings the projectile to earth unless it is stopped by something else, such as a wall, a body of water, or a living being.

When the projectile hits a target, it will penetrate some distance and deform (such as into a mushroom shape). The forces of yaw, pitch, and roll may increase. All these actions add to the amount of energy transferred from the projectile into the target. For a target like a piece of paper, penetration without deformation is common, so much of the kinetic energy of the projectile passes through. For a target like a steel wall, penetration may be almost nil and almost all the projectile’s kinetic energy is absorbed in deformation and ricochet. For a target like the center of mass of a human body, penetration, yaw, pitch, roll, and ricochet all usually occur. This imparts the maximum energy to the body and causes the most damage, which is probably exactly what the shooter hoped to do.

Nature of Gunshot Wounds

A bullet hitting a human body immediately compresses the underlying skin, flesh, and bone. The pressure typically exceeds the elasticity of those structures and tears or breaks them.[9] The skin rebounds, leaving an entrance hole which is small than the diameter of the bullet. Once inside the body, the bullet crushes and displaces tissue, forming two cavities, one permanent and the other temporary. Gunpowder stains and soot can be found close to entrance wounds.

Entrance wounds

1. Smaller than exit wound
2. Margins inverted, surrounded by dirt or grease.
3. Pink coloration
4. Blackening, tattooing, muzzle imprint, hair singed, lead ring, seared margins

Exit wounds

1. Larger and more irregular due to bullet tumbling and deformation
2. No blackening or imprints like entrance wounds.
3. Shape may resemble a slit, a crescent, or a star.

What are the factors which cause wounding by projectiles?

1. Penetration – the projectile must enter the skin if it is to cause any more than bruising. Handgun and especially rifle rounds will sometimes penetrate their target completely. If they do, they carry some of the energy out of the target, not depositing it all into the victim.
2. Permanent cavity – caused by the projectile directly killing tissue.
3. Temporary cavity – when the projectile transfers kinetic energy to the surrounding tissue, that tissue accelerates away from the projectile. When the energy dissipates, that tissue recoils back its original position if possible. Some mammalian tissues like brain, spleen,  and liver do not recoil but are permanently damaged.
4. Fragmentation – a bullet or other projectile entering tissue will likely hit something else, like clothes or bone. These solid particles will themselves become missiles, following their own pathways and imparting energy and damage to whatever they encounter.  
5. Extravasation – the energy in the projectile is transferred to the surrounding tissues and forces blood and other fluids out. The zone of extravasation is 12 times the size of the temporary cavity and 27 times the size of the permanent cavity. Extravasation is temporary.

Shotguns

Shotguns fire multiple small and relatively slow round pellets from unrifled barrels. Depending upon the size of the projectile, a single shot can fire one, a few, or dozens of pellets. Multiple pellets begin to scatter immediately upon leaving the barrel so the shotguns can do tremendous damage at close range but little or no damage at longer ranges.

Distance between shooter and target

1. Up to five meters – pellets have not scattered too much and so hit the target as a large mass. A tremendous amount of kinetic energy has been transferred to the target and the wounding is extensive. Shotgun pellets rarely penetrate all the way through their target, and so deposit all their energy into the victim.  
2. Five to twelve meters – pellets have scattered significantly so some pellets do not even hit the target. Energy transfer is much less, but damage can still be life-threatening. Fractures are rare. Ocular injuries can occur. Pellets which enter blood vessels can be carried with the blood and cause emboli.
3. More than twelve meters – little damage with only a few pellets hitting and penetration stopped at skin.

In close range shotgun wounds, the wad can be found near the entrance wound. Gunpowder stains are also common.

Management of Gunshot Wounds (GSW)

In emergency services (fire, police, EMS, disaster, etc.), management begins with the ABCs.

Table 2 – Medical Management

Basics	Notes	Action
Airway	GSWs, especially to the face, head, and neck, can do significant damage to the airway	Find airway, use jaw thrust if possible to open it. Remove foreign bodies and loose teeth. Secure airway with intubation or cricothyrotomy if necessary and if resources are available.
Breathing		Begin assisted breathing if necessary
Circulation	GSW damage	Start CPR if no pulse. Stop any obvious bleeding with direct pressure and tourniquets as needed.
Disability	GSWs can badly damage the central nervous system	Evaluate via AVPU (alert, verbal, physical, unresponsive) or the Glasgow Coma Scale.
Exposure	Look for associated wounds, including knife, bludgeon, and other GSW.	Treat as necessary. If resources are limited, triage.

GSWs are not sterile. Skin flora and microorganisms on clothing are carried into the wound by the projectile. Bullets traversing sinuses and the GI tract are especially prone to infection. Broad spectrum antibiotics should be given proactively. Tetanus prophylaxis is also mandatory.  

Notes: (A) There was evidence of an acute comminuted burst fracture of the humerus including the head, neck, and proximal metadiaphysis with extensive pectoralis muscle damage, a partial laceration to the cephalic vein, and a large missing bone void of the humeral head. On radiograph, multiple free-floating metallic bullet fragments were found with the largest metallic bullet fragment measuring 1.5 cm (B and C). The wound was irrigated, and all free-floating bone fragments and necrotic or loose tissue were removed. (D) The humeral shaft fragments, articular fragments, and proximal humerus fracture were reduced. An extended Synthes small fragment plate was placed spanning both the humeral neck and shaft fractures and bone graft was applied into the bone void of the neck.

Notes: (A) Initial clinical photograph reveals a 9×5 cm wound from the gunshot injury. (B) The patient sustained a comminuted fracture of the second metacarpal with segmental bone loss and two accompanying bullet fragments. The fracture site was treated with an intramedullary headless nail and a combination of crushed bone allograft, demineralized bone matrix (DMX) puddy, and bone venous blood. (C) Radiographs eight months after the injury show persistent retained fragments.

Notes: (A) The gunshot injury to the abdomen was retained anterior to L3 vertebra with accompanying comminuted fractures of the L3 and left lateral L4 vertebrae. One bullet notably struck the femoral shaft, resulting in comminuted fracture of the midshaft with multiple bullets fragments. Entry and exit wounds on radiographs are indicated with paper clips (B and C). (D) The femoral fracture was fixated with an intramedullary nail.

Notes: Clinical photographs show a traumatic wound measuring 16×16 cm with significant muscular, fascial, nervous and vascular injury (A and B). Comminuted and markedly displaced fractures through the mid diaphysis of the tibia and fibula with extensive shrapnel are evident on initial radiographs (C and D). A total of 16 operations were performed for this injury. During the initial operation, small pieces of fabric, bone, and metallic objects were removed, the tibial nerve was repaired, ligation of posterior tibial artery and vein was performed, and a tibial external fixator was placed. Five repeat I&D procedures were performed before the tibia was fixated with an intramedullary nail and a latissimus dorsi free flap was placed and then skin grafted (E and F). Later operations included repeat I&D and treatment of the tibial nonunion with bone grafting.

Body Armor

The earliest evidence of body armor in human history dates from the Sumerian Era, thousands of years before Christ. Leather and thick fabric were the earliest types, but these provided little protection from penetrating wounds caused by arrows, spears, and other missiles. Brigandine armor is armor that consists of pieces of metal riveted to a cloth, leather, or canvas backing.

Celts began making rings of metal and attaching them to other rings (4:1, 6:1) to form a strong and flexible armor known as chainmail. In 1300-1500, armor with plates of metal covering the whole body appeared. Heavy cavalry, knights and horses in plate armor charging across the battlefield, was a terrifying weapon against untested foes.

Plate armor fell into disuse since rifle and machine gun bullets, as well as shrapnel from shells, readily penetrated it. Armor made of ceramics (like boron carbide) and fibers (like Kevlar), when fitted with metal or ceramic plates, could stop most edged and missile weapons. Soldiers, police, investigators, security personnel, and others wear such armor today.

Conclusion

Police, Fire, EMS, and other professionals in emergency response will confront ever growing numbers of gunshot wounds (GSW). GSWs are often terrible, with high mortality and high disability for most of those who survive. Patients need the best care that we can possibly provide, and good training improves the care we give. First responders also are themselves victims of GSWs.   

References

1. Mohamed Rahil, Gunshot Wounds, https://www.slideshare.net/mohamedrahilalhadithy/gunshot-wounds.
2. Tejasvi Bhatia, Classification of gunshot wounds, https://www.slideshare.net/TejasviBhatia/classification-of-gunshot-wounds.
3. Annual Report on Firefighter Fatalities in the United States, US Fire Administration https://www.usfa.fema.gov/statistics/reports/firefighters-departments/firefighter-fatalities.html.
4. Body armor, https://en.wikipedia.org/wiki/Body_armor.
5. BulletProof Zone

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[1] https://www.statista.com/statistics/249740/percentage-of-households-in-the-united-states-owning-a-firearm/.

[2] https://shootingindustry.com/discover/firearms-report-2022/.

[3] https://datavisualizations.heritage.org/firearms/defensive-gun-uses-in-the-us/.

[4] For comparison, the speed of sound is about 340 m/s, so most firearm projectiles exceed the speed of sound.

[5] Some muskets did have rifling, but this was a later development.

[6] A few early rifles were muzzle loaded.

[7] Muzzle velocities cover a broad and overlapping range. Muzzle velocity is measured just outside the tip of the barrel.  

[8] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9462949/.

[9] Admiral Husband W. Kimmel, the commander of the US Pacific Fleet at Pearl Harbor, was grazed across the chest by a spent .50 caliber round in his office at Pearl Harbor on 7 Dec 1941. He said, “It would have been merciful had it killed me.”