A gunshot wound, or GSW, is a medical term used to describe an acute traumatic injury caused by a projectile fired from a firearm. It represents a severe form of penetrating trauma. The severity of a GSW stems from the projectile’s ability to transfer immense kinetic energy into the body’s tissues, leading to complex internal damage often disproportionate to the size of the external entry point. Because of the risk to major organs, blood vessels, and bone, a GSW is universally treated as a time-critical surgical emergency.
Defining the Gunshot Wound
A GSW is fundamentally a wound of energy transfer, with the projectile delivering ballistic force into the body. The physics governing the injury shows that a projectile’s energy is proportional to its mass but proportional to the square of its velocity. This relationship means that velocity is the single most significant factor in determining the destructive potential of a bullet.
Projectiles are broadly categorized into low-velocity and high-velocity types, with a common threshold being 2,000 feet per second. Low-velocity projectiles, typically from handguns, generally cause tissue damage primarily along the direct path of the bullet, creating a permanent wound channel. High-velocity projectiles, often from rifles, carry significantly more energy due to their speed. This elevated energy transfer pushes the soft tissues away from the bullet’s path, drastically increasing the severity of the injury.
The projectile’s design and behavior within the body also influence the extent of damage. Factors like yaw, or the deviation of the bullet from its straight line of flight, and fragmentation increase the amount of tissue contact and energy dumped into the body. A bullet that tumbles or breaks apart will create a much larger and more erratic wound path than a stable, non-deforming projectile.
Classifying GSW Injuries
Medical professionals categorize gunshot wounds primarily based on the trajectory and presence of both entry and exit sites, which helps inform surgical planning. The most common classification distinguishes between penetrating and perforating wounds, describing the path the projectile takes through the body.
A penetrating wound occurs when the projectile enters the body but does not exit, remaining lodged in the tissue. A perforating wound is one in which the projectile enters the body and subsequently exits, creating two distinct external wounds. The exit wound is often larger and more irregular than the entry wound because the bullet has typically tumbled, deformed, or carried fragments of bone and tissue with it as it exits. Determining the exact path, or trajectory, between the entry and exit points is a crucial step for the surgical team to predict which internal structures may be damaged.
A less severe category is the tangential or grazing wound, where the projectile strikes the body at a shallow angle and only causes a surface-level injury. Identifying the characteristics of the entry and exit wounds is important for immediate surgical planning and forensic documentation.
Trauma Protocol and Immediate Stabilization
The response to a GSW is governed by a time-sensitive, standardized medical framework that begins at the scene and continues in the emergency department. This process is often driven by the concept of the “Golden Hour,” which refers to the period following a traumatic injury during which immediate intervention offers the highest chance of survival. The primary goal of this initial phase is to stabilize the patient by addressing all immediate threats to life before definitive surgical repair can occur.
The initial assessment of a GSW patient follows the systematic ABCDE trauma protocol, which prioritizes interventions in a specific order:
- Airway maintenance and cervical spine protection.
- Breathing and ventilation assessment to ensure oxygenation.
- Circulation, which focuses on controlling massive hemorrhage and preventing hypovolemic shock. For external life-threatening bleeding, teams will immediately apply direct pressure, use hemostatic dressings, or place tourniquets on limbs.
- Disability, which involves a rapid neurological assessment.
- Exposure, where the patient is fully undressed to identify all injuries while simultaneously preventing hypothermia.
The control of hemorrhage is frequently considered the most time-sensitive step, and some advanced protocols now place Massive hemorrhage control first in a sequence known as MARCH. Stabilizing the patient’s blood pressure and replacing lost volume with blood products are preparatory steps taken before the patient is moved to the operating room.
Understanding the Internal Damage
The projectile’s energy creates a permanent wound channel by crushing and lacerating the tissue directly in its path. However, a more significant destructive force, especially with high-velocity rounds, is the creation of a temporary cavity, known as cavitation. This temporary cavity is a space formed as the tissue radially stretches away from the projectile’s path, reaching a diameter many times the size of the bullet itself before collapsing.
This rapid stretching and collapsing of the temporary cavity causes tissue damage far outside the permanent wound track, particularly in less elastic organs like the liver, spleen, and brain. The resulting tissue death and disruption can lead to immediate systemic shock, usually of the hemorrhagic type, from the rapid loss of blood volume. While the concept of hydrostatic shock is debated, the mechanical effects of cavitation alone are enough to cause widespread injury.
Surgeons address this internal destruction through a strategy known as damage control surgery, which prioritizes controlling bleeding and contamination over immediate, complex repair. The initial operation focuses on stopping hemorrhage, temporarily closing perforations in hollow organs, and removing non-viable tissue. Definitive repair of organs, vessels, and complex fractures is often deferred to a second, more stable operation days later, once the patient has recovered from the initial shock.