Information Bulletin Number 0707077

CDC: Blast Injuries

With the recent developments in London, the CDC has re-posted this "fact sheet" on Blast Injuries. It has been reproduced here as an FYI and an opportunity to become familiar with blast injuries.

Blast Injuries: Essential Facts
Key Concepts

. Bombs and explosions can cause unique patterns of injury seldom seen outside combat
. Half the initial casualties 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
. Most injuries involve multiple penetrating wounds and blunt trauma
. Confined space explosions (buildings, vehicles, mines) and explosions resulting in structural collapse lead to greater morbidity and mortality
. Primary blast injuries among survivors usually result from confined-space explosions
. Standard protocols apply for triage, trauma resuscitation, treatment, and transfer

Blast Injuries:

-Primary: Injury from overpressurization force (blast wave) impacting the body surface (i.e., TM rupture, pulmonary damage, hollow viscus rupture)
-Secondary: Injury from projectiles such as bomb fragments or flying debris (i.e., penetrating trauma, blunt trauma)
-Tertiary: Injuries from displacement of victim by the blast wind or structural collapse (i.e., crush injuries, blunt/penetrating trauma, fractures, traumatic amputations) Quaternary: Other injuries from the blast (i.e., burns, asphyxia, toxic exposures)

Primary Blast Injury:
Lung Injury

. Signs are usually present at initial evaluation, but may be delayed up to 48 hours
. More common among patients with skull fractures, greater than 10% BSA burns, or penetrating injury to the head or torso
. Presentation varies from scattered petechiae to confluent hemorrhages
. Suspect in anyone with dyspnea, cough, hemoptysis, or chest pain following blast
. Characteristic "butterfly" pattern produced on CXR
. Sufficient high-flow O2 to prevent hypoxemia is administered via NRB mask, CPAP, or ET tube
. Fluid management is similar to that of pulmonary contusion; ensure adequate tissue perfusion, but avoid volume overload
. Endotracheal intubation mandated for massive hemoptysis, impending airway compromise, or respiratory failure

- Selective bronchial intubation may be necessary for significant air leaks or massive hemoptysis
- Positive pressure ventilation may result in alveolar rupture or air embolism

. Clinical signs of pneumothorax or hemothorax require prompt decompression
. Prophylactic chest tube must be considered before general anesthesia or air transport
. Air embolism can present as stroke, MI, acute abdomen, blindness, deafness, spinal cord injury, or claudication

Blast Injuries: Essential Facts

- Administer high-flow O2; prone, semi-left lateral, or left lateral positioning
- Transfer for hyperbaric O2 therapy may be considered

Abdominal Injury:

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

Ear Injury:

. Tympanic membrane is the most common primary blast injury
. Signs of ear injury are usually evident on presentation (hearing loss, tinnitus, otalgia, vertigo, bleeding from external canal, otorrhea)
. Isolated TM rupture is not a marker for morbidity

Other Injury:

. Traumatic amputation of a limb is a marker for multisystem injuries
. Concussions are common and easily overlooked; symptoms of mild TBI and post-traumatic stress disorder can be similar
. Grossly contaminated wounds are candidates for delayed primary closure
. Compartment syndrome, rhabdomyolysis, and acute renal failure are associated with structural collapse, prolonged extrication, severe burns, and some poisonings
. Exposure to inhaled toxins (CO, CN, MetHgb) must be considered in industrial and terrorist explosions
. Significant percentage of survivors have serious eye injuries

Disposition:

. No definitive guidelines exist for observation, admission, or discharge
. Discharge decisions depend on associated injuries
. Second- and third-trimester pregnancies should be admitted for monitoring
. Follow-up is needed for wounds; head injury; and eye, ear, and stress-related complaints
. Patients with ear injury may have tinnitus or deafness and need written instruction

For more information, visit http://www.bt.cdc.gov/masscasualties, or call CDC at 800-CDC-INFO (English and Spanish) or 888-232-6348 (TTY).

Source: CDC