Blast injuries present unique triage, diagnostic, and management challenges as a consequence of the blast wave itself. This is referred to as primary blast injury (PBI). Blasts produce a pressure wave that moves out from the center of the explosion at supersonic speed. Primary blast injury is due solely to the direct effect of the pressure wave on the body. The magnitude of the wave depends on the size of the explosion and the environment in which it occurs: the more powerful the blast, the greater the damage. The effects of the blast wave are increased in a closed space such as a building or bus and underwater. Primary blast injury occurs almost exclusively in gas-containing organs: the ear, the respiratory tract, and the GI tract.
Other blast injuries include Secondary Blast Injuries: those injuries caused by flying debris caused by the blast. In many terrorist bombings, casualties have multiple penetrating wounds caused by shrapnel deliberately put into the bomb to cause extensive injuries.
Tertiary Blast Injuries are by propulsion of the body by the shock wave into solid objects. Head, spine and extremity injuries are common.
Finally, Quaternary or Miscellaneous Blast Injuries are other sequelae of the blast, often including crush injury and crush syndrome resulting from the collapse of a building or other structure. Other injuries include burns and inhalation injuries.
Key Concepts
- Bombs and explosions can cause unique patterns of injury seldom seen outside combat.
- The predominant post explosion injuries among survivors involve standard penetrating and blunt trauma. Blast lung is the most common fatal injury among initial survivors.
- Explosions in confined spaces (mines, buildings, or large vehicles) and/or structural collapse are associated with greater morbidity and mortality.
- Half of all initial casualties will seek medical care over a one-hour period. This can be useful to predict demand for care and resource needs.
- Expect an “upside-down” triage - the most severely injured arrive after the less injured, who bypass EMS triage and go directly to the closest hospitals.
Background
Explosions can produce unique patterns of injury seldom seen outside combat. When they do occur, they have the potential to inflict multi-system life-threatening injuries on many persons simultaneously. The injury patterns following such events are a product of the composition and amount of the materials involved, the surrounding environment, delivery method (if a bomb), the distance between the victim and the blast, and any intervening protective barriers or environmental hazards. Because explosions are relatively infrequent, blast-related injuries can present unique triage, diagnostic, and management challenges to providers of emergency care.
Few U.S. health professionals have experience with explosive-related injuries. Vietnam era physicians are retiring, other armed conflicts have been short-lived, and until this past decade, the U.S. was largely spared of the scourge of mega-terrorist attacks. This primer introduces information relevant to the care of casualties from explosives and blast injuries.
The ATS has served as the Lead TIIDE agency for the development of a Blast Injuries Monograph and 17 Blast Injury Fact Sheets that provide just-in-time teaching for clinicians dealing with the sequelae of blasts and bombings.