<< Ballistic Injuries In The Emergency Department (Trauma CME)

History

If the patient’s overall status permits, certain historical information may help the clinician in management. If the patient is unable to provide any historical information, EMS personnel or friends/family present may be able to assist with providing information. Per ATLS® protocol, an “AMPLE” history should be taken at a minimum (see Table 4) along with the following questions.²⁸

• What type of weapon was used? Handguns are low-velocity weapons and typically involve less kinetic energy transfer than high-velocity rifles or the variable force and pattern of shotgun injuries. If the patient or witness can tell you the type of gun used, it may help you anticipate unseen injuries.
• How far away were you from the weapon at the time it was fired and at what angle were you when it hit? This may help to anticipate the missile’s trajectory and possible pathway through the body in order to determine which skin wound is the likely entrance wound and to anticipate potential injury patterns and locations.
• How many shots did you hear? There may only be 2 visible surface injuries, which can lead you to assume entry and exit wounds, but if there were 2 shots fired, possibly neither bullet found an exit track and both are still inside the patient. This will also prompt you to continue to look for more missile wounds that may not initially be visible.

Curiosity will often lead the emergency clinician to ask about the circumstances of the ballistic injury, but these details are rarely helpful except to determine whether the wound was self-inflicted, which will require later psychiatric evaluation after the traumatic injuries are addressed and the patient is stabilized. For more information on assessing depressed and suicidal patients in the ED, see the September 2011 issue of Emergency Medicine Practice, “The Depressed Patient And Suicidal Patient In The Emergency Department: Evidence-Based Management And Treatment Strategies.” Tetanus status should be obtained, and prophylaxis is indicated for most gunshot wounds.

Physical Examination

Assessment of patients with ballistic trauma should proceed according to the ATLS® protocol, with stabilization of the airway and rapid attention to immediately life-threatening injuries. Often, history, examination, and treatment must occur simultaneously. Certain initial impressions such as agitation or combativeness, hypoxia or respiratory distress, diaphoresis, and an unwillingness to lie flat may suggest pending hemodynamic collapse.^₂₈ Full exposure of the patient – including the back – is necessary to evaluate the number of wounds present. Vital sign abnormalities (hypoxia, tachycardia, hypotension) suggest a serious underlying injury. Initially, normal signs can be insensitive as an indicator of significant injury and need to be continually reassessed for deterioration.

The primary survey is performed immediately upon arrival, with an orderly evaluation of immediately life-threatening injuries, starting with the airway and progressing to assessment of breathing and circulation. Often, a team approach is utilized for the sake of efficiency. After addressing the ABCs, further evaluation of neurologic disability and complete exposure of the patient take precedence before proceeding to the secondary survey. At any point, note the life- or limb-threatening injuries and address treatment of those specific injuries.²⁸

Many vital structures are at particular risk from ballistic trauma, including the lungs, heart, great vessels, esophagus, and tracheobronchial tree; failure to address these immediately can lead to death. The location of the external wounds may suggest a track for the projectile, but physical examination is generally inadequate to determine the direction and extent of the penetrating projectiles due to the cavitation effects of the projectile through body tissues. A small external wound may belie massive internal injuries that are not immediately evident on history and physical examination. Penetrating projectiles are frequently known to ricochet on bony structures, thus altering the trajectory of the permanent cavity produced. High-velocity ballistic missiles create a large temporary cavity that can lead to significant tissue damage.

The patient presenting to the ED with penetrating injury to the neck from a gunshot wound can have a variety of presentations. Airway involvement may be indicated by dyspnea, crepitus, air bubbling from a wound, dysphonia, or hemoptysis. Great vessel involvement may be obvious, presenting with “hard” signs of vascular injury such as active hemorrhage, expanding hematoma, pulse deficit, or a bruit or thrill. (See Table 5.) However, great vessel involvement may be more insidious, presenting only with “soft” signs of vascular injury such as a nonpulsatile hematoma, nervous system ischemia, or proximity to a major vessel. Esophageal injury may be asymptomatic initially but may also present with dysphagia, hematemesis, drooling, or odynophagia.

Emergency clinicians often refer to the areas of the body at risk for cardiac and mediastinal injuries as “the box,” which is the area bounded superiorly by the clavicles and sternal notch, inferiorly by the costal margins, and laterally by the nipple line. However, injuries outside of the box, such as posterior and lateral chest wounds, can traverse the mediastinum as well.²⁷ While a thorough physical examination is always necessary, in many of these cases, diagnostic tests are required to delineate the extent of injuries.

Rapid reversal of hypoxia is often necessary, with supplemental oxygen and airway control if the patient is unable to protect his own airway or respiratory distress is present. Immediately perform an evaluation of the lungs to ascertain shortness of breath, pleuritic chest pain, and decreased breath sounds concerning for pneumothorax or hemothorax. Obvious deformities of the chest wall, asymmetric chest rise, and tracheal deviation can be initial signs of a significant pneumothorax. Many of these findings on physical examination warrant placement of a large (36 French) thoracostomy tube before proceeding with further management or while other members of the trauma team continue their evaluation.²⁸

Listen for muffled heart sounds and assess for jugular venous distension as indicators of a traumatic cardiac tamponade. Hypotension is an ominous sign for hemorrhagic shock and ongoing internal bleeding from cardiac or great vessel injuries. Diminished distal pulses can also be an indicator of vascular or cardiac injury.

Chest wall crepitus or the sensation of a foreign body in the throat heightens the concern for esophageal or tracheobronchial injury. Because diaphragmatic injuries can occur in up to 19% of penetrating thoracoabdominal trauma cases and in up to 59% of patients with gunshot wounds to the left lower chest, examination of the abdomen for peritonitis is also warranted early in the primary survey.^29,30 Undress the patient completely to evaluate for the location of the wound(s) and other injuries. Log-roll the patient to assess for entrance or exit wounds posteriorly, and consider a rectal examination to assess for gross blood and rectal tone.

Documentation of the pulse strength and character as well as the skin temperature, color, and capillary refill in comparison to the unaffected limb is essential. Pay special attention to presence or absence of these hard signs of vascular injury since they generally warrant operative management.^31,32 (See Table 5.) Angiography in these patients may lead to the complications associated with unnecessary testing and surgical exploration.³³ Some authors have suggested that soft signs do not correlate with a vascular injury at all.^34,35

Early realignment of a grossly deformed extremity is recommended to provide hemostasis and pain relief. If a bleeding vessel is visualized, hemostasis should be obtained by direct pressure or tourniquet. Clamping of a vessel is not recommended due to the risk of further injury to the vessel and unintentional injury of adjacent nerves. Wounds should not be explored digitally or with instruments unless gross decontamination of clothing or debris is required.

Arterial pressure indices (APIs) can be used to improve diagnostic accuracy for vascular injuries and are readily performed at the bedside. The APIs are calculated by dividing the systolic blood pressure (SBP) distal to the injury of the extremity in question by the similarly located SBP of the uninjured extremity. An API is considered abnormal if the result is < 0.9, and studies have suggested that API is 95% sensitive and 97% specific for a major arterial injury. An API of < 0.5 suggests a serious single-segment or multisegment arterial injury.³²