Blast injury

Blast injury is a syndrome (set of symptoms) resulting from an explosion. This is an injury caused by the impact of a pressure/shock wave on the human body. The essence of an explosion is a rapid transformation of energy (chemical, nuclear, etc.) which leads to a rapid increase in temperature and gas pressure at the site of the explosion and the expansion of the explosion waste products into the surroundings.

Injuries
The energy of a propagating shock wave is released whenever it passes through an acoustic impedance interface. Typically at the interface soft tissue - air or soft tissue - bone. The extent of injury depends on the intensity and duration of exposure.


 * Primary injuries


 * Caused by a pressure wave (gas, liquid, solid substance).
 * They occur most often when a person is close to the source of the explosion (land mine).
 * Most effected are organs that contain air (first middle ear injury manifests itself, then the lungs (contusion, bleeding, alveoli damage), the intestine (injury manifests itself after several hours), ...)
 * The brain is also traumatized.
 * A primary injury is characterized by the absence of external injuries so the severity and extent of the injuries are often unrecognized or underestimated.


 * Secondary injuries


 * The remains of objects that are thrown into the surroundings by the explosion play their role here.
 * This includes penetrating and perforating trauma with visible bleeding or bleeding into internal organs. The presence of shrapnels significantly complicates treatment.


 * Tertiary injuries


 * This is an injury to the extent of amputation caused by a strong hit of air or the impact of the human body against an obstacle. Often accompanied by penetrating injuries.


 * Indirect injuries


 * Arising in a different context (e.g. building collapses, being trampled by a crowd), burns, crush syndrome.

Distance from the epicenter

 * 1) epicenter - devastating, fatal injuries
 * 2) primary zone – pressure wave effecting the middle ear or lungs


 * in an open space: the shock wave propagates spherically, reflects off the ground and standing objects; overpressure is followed by a wave of underpressure and rapid normalization of pressure ratios
 * in a closed space: the pressure wave is reflected and the overpressure lasts longer, the proportion of primary injuries increases; on the contrary, the proportion of shrapnel injuries decreases due to obstacles (e.g. bus seats)
 * immersion blast syndrome (propagation of a pressure wave in a liquid)
 * especially abdominal contusion with intestine ruptures, eyeball contusions
 * solid blast syndrome (propagation of a pressure wave in a solid environment)
 * multiple fractures of the limbs (for those who were standing at the time of the explosion), pelvis and spine (for those who were sitting)

Injury to individual organs

 * 1) ear – perforation of the eardrum with possible hearing damage
 * 2) lungs – rupture of the alveolocapillary membrane accompanied by bleeding and air embolization into the arteries of the brain and heart; emphysema and pneumothorax can also occur
 * 3) heart – the injury may subsequently be accompanied by heart rhythm disorders
 * 4) GIT – contusion or perforation of the intestinal wall
 * 5) limbs – amputation of peripheral parts of limbs
 * 6) muscles - crush syndrome and subsequent rhabdomyolysis

Treatment of injured in the explosion

 * surgical treatment – ​​where indicated (fractures, intestinal ruptures, etc.)
 * otherwise conservative procedure
 * ensuring breathing (intubation, cricothyrotomy, oxygen therapy) and blood circulation (cardiotonics, shock treatment)
 * prevention and treatment of pulmonary complications (antibiotics)