Acute Care 23: Blast Injuries

Key Concepts

Bombs and explosions can cause unique patterns of injury seldom seen outside combat
Expect half of all initial casualties to seek medical care over a one-hour period
Most severely injured arrive after the less injured, who bypass EMS triage and go directly to the closest hospitals
Predominant injuries involve multiple penetrating injuries and blunt trauma
Explosions in confined spaces (buildings, large vehicles, mines) and/or structural collapse are associated with greater morbidity and mortality
Primary blast injuries in survivors are predominantly seen in confined space explosions
Repeatedly examine and assess patients exposed to a blast
All bomb events have the potential for chemical and/or radiological contamination
Triage and life saving procedures should never be delayed because of the possibility of radioactive contamination of the victim; the risk of exposure to caregivers is small
Universal precautions effectively protect against radiological secondary contamination of first responders and first receivers
For those with injuries resulting in non-intact skin or mucous membrane exposure, give hepatitis B immunization (within 7 days) and age-appropriate tetanus toxoid vaccine (if not current). Consider HIV prophylaxis discussion.

Blast Injuries

Primary: Injury from over-pressurization force (blast wave) impacting the body surface

Crush injuries, burns, asphyxia, toxic exposures, exacerbations of chronic illness

Primary Blast Injury

Signs usually present at time of initial evaluation, but may be delayed up to 48 hrs
Reported to be more common in patients with skull fractures, >10% BSA burns, and penetrating injury to the head or torso
Varies from scattered petechiae to confluent hemorrhages
Suspect in anyone with dyspnea, cough, hemoptysis, or chest pain following blast
CXR: “butterfly” pattern
High flow O₂ sufficient to prevent hypoxemia via NRB mask, CPAP, or ET tube
Fluid management similar to pulmonary contusion; ensure tissue perfusion but avoid volume overload
Endotracheal intubation for massive hemoptysis, impending airway compromise or respiratory failure

Consider selective bronchial intubation for significant air leaks or massive hemoptysis
Positive pressure may risk alveolar rupture or air embolism

Prompt decompression for clinical evidence of pneumothorax or hemothorax
Consider prophylactic chest tube before general anesthesia or air transport
Air embolism can present as stroke, MI, acute abdomen, blindness, deafness, spinal cord injury, claudication

Gas-filled structures most vulnerable (esp. colon)
Bowel perforation, hemorrhage (small petechiae to large hematomas), mesenteric shear injuries, solid organ lacerations, and testicular rupture
Suspect in anyone with abdominal pain, nausea, vomiting, hematemesis, rectal pain, tenesmus, testicular pain, unexplained hypovolemia
Clinical signs can be initially subtle until acute abdomen or sepsis is advanced

Tympanic membrane most common primary blast injury
Signs of ear injury usually evident on presentation (hearing loss, tinnitus, otalgia, vertigo, bleeding from external canal, otorrhea)

Other Injury

Traumatic amputation of any limb is a marker for multi-system injuries
Concussions are common and easily overlooked
Consider delayed primary closure for grossly contaminated wounds, and assess tetanus immunization status
Compartment syndrome, rhabdomyolysis, and acute renal failure are associated with structural collapse, prolonged extrication, severe burns, and some poisonings
Consider possible exposure to inhaled toxins (CO, CN, MetHgb) in industrial and terrorist explosions
Significant percentage of survivors will have serious eye injuries

Disposition

No definitive guidelines for observation, admission, or discharge
Discharge decisions will also depend upon associated injuries
Admit 2nd and 3rd trimester pregnancies for monitoring
Close follow-up of wounds, head injury, eye, ear, and stress-related complaints
Patients with ear injury may have tinnitus or deafness; communications and instructions may need to be written