Blast injures

There are 4 types of blast injury & an individual patient may be injured by more than one mechanism :

 

Primary: Injury from over-pressurization force (blast wave) impacting the body surfaceTM rupture, pulmonary damage and air embolization, hollow viscus injurySecondary: Injury from projectiles (bomb fragments, flying debris)Penetrating trauma, fragmentation injuries, blunt traumaTertiary: Injuries from displacement of victim by the blast windBlunt/penetrating trauma, fractures and traumatic amputationsQuaternary: All other injuries from the blastCrush injuries, burns, asphyxia, toxic exposures, exacerbations of chronic illness

 

 

Primary Blast Injuries : The pressure wave hits the body and, while most of it is reflected, some of it manages to compress internal gases. As a result, the victim sustains primary blast injuries.

Spalling,( Turbulence at Air/liquid interface ) [ POTENTIAL Q. ]Implosion,Inertia,and pressure differentials are the main mechanismsinvolved in the pathogenesis of primary blast injuries.

 

These typically affect ears ( Tympanic membrane most common primary blast injury ), the lungs, and -- in rare cases -- intestines (esp. colon*) These gassy chambers basically implode, rupturing and fragmenting tissue.

 

 

Blast lungs refers to severe pulmonary contusion, bleeding or swelling with damage to alveoli and blood vessels, or a combination of these. It is the most common cause of death among people who initially survive an explosion.

CXR:  “ butterfly” pattern**

 

In air the gas & air surrounding the explosion are compressed & absorb energy from the explosion. 

 

In water, being incompressible, there is little absorption & the pressure wave is transmitted with greater intensity over a longer range. 

 

--> The lethal range of an explosion in water is far greater than the same mass of explosion in air & this increases mortality in underwater explosions.

 

Most Severely Affected Organs**: 

Air Blast : Lungs

Underwater : G.I.T

 

Most Common :

 

Air : Tympanic membrane

Under Water(fully submerged) T.M

Underwater ( Head is Out ) G.I.T