Gunshot Trauma it’s mechanism of injury and it’s classification

Gunshot Trauma it’s mechanism of injury and it’s classification

1. Gunshot Trauma Made by: Ahmed Soker,Haneen Hamdy,Salma Kordi

2. DEFINITION Gunshot injuries occur when someone is shot by a bullet or other sort of projectile from a firearm. Peace time gunshot injuries occur in a variety of different situations - criminal and terrorist incidents (including shots fired by law enforcement agents), attempted suicides as well as unintended firearm 'accidents' (both civilian and amongst the armed forces

3. Mechanism of injury There are many different types of bullets but the most common type is composed of a lead core with some type of casing. On striking, the projectile element may travel at speeds of up to 1,500 meters/second , dependent on the ammunition and type of gun. The most important factors in causing significant injury or death are their placement and projectile path. The head and torso are the most vulnerable areas, with incapacitation due to CNS disruption or massive organ destruction and hemorrhage. The extent of tissue and organ trauma will depend on terminal ballistics, which are influenced by the type of bullet, its velocity and mass as well as the physical characteristics of the penetrated tissue.

4. Injury is inflicted in a number of ways: Firstly, the projectile crushes structures along its track, similar to other forms of penetrating injury. Temporary cavitation causes shearing and compression, sometimes tearing structures (as with solid abdominal viscera) or stretching inelastic tissue (the brain is particularly susceptible), analogous to blunt trauma. As tissues recoil and hot gases dissipate, soft tissue collapses inwards with the permanent cavity being the resultant defect. Bullets which display greater yaw will be associated with increased temporary cavitation . Secondly, kinetic energy transfer occurs during retardation of the bullet and this may cause damage outside the tract. Factors influencing the efficiency of kinetic energy transfer include: Kinetic energy of a body which is proportional to mass and velocity. Projectile's deformation and fragmentation. Entrance profile and path travelled through the body. Biological characteristics of the transit tissues. Projectiles tend to be classified as low-velocity (<300 hm /second) or high-velocity (>300 hm /second). Those with higher velocity may be expected, on this basis, to dissipate more energy into surrounding tissue as they slow and cause more tissue damage but this is only a very approximate guide. This 'kinetic energy dump' theory is controversial, since high-velocity injuries are frequently less extensive than would be predicted and fragmentation appears to be the most effective mechanism for wounding rather than yawing or other mechanisms for slowing high-velocity rounds quickly.

5. Classification Gunshot wounds are classified according to the speed of the projectile using the  Gustilo open fracture classification : Low-velocity: Less than 1,100 ft/s (335 m/s) Low velocity wounds are typical of small  caliber   handguns  and display wound patterns like Gustilo Anderson Type 1 or 2 wounds Medium-velocity: Between 1,200 ft/s (366 m/s) and 2,000 ft/s (610 m/s) These are more typical of shotgun blasts or higher caliber handguns like magnums. The risk of infection from these types of wounds can vary depending on the type and pattern of bullets fired as well as the distance from the firearm. High-velocity: Between 2,000 ft/s (610 m/s) and 3,500 ft/s (1,067 m/s) Usually caused by powerful assault or hunting rifles and usually display wound pattern similar to Gustilo Anderson Type 3 wounds. The risk of infection is especially high due to the large area of injury and destroyed tissue.

6. Kronlein shot The Kronlein shot is a distinctive type of headshot wound that can only be created by a high velocity rifle bullet or shotgun slug.In a Kronlein shot, the intact brain is ejected from the skull and deposited some distance from the victim's body.This type of wound is believed to be caused by a hydrodynamic effect. Hydraulic pressure generated within the skull by a high velocity bullet leads to the explosive ejection of the brain from the fractured skull.

7. Management Initial assessment for a gunshot wound is approached in the same way as other acute trauma using the  advanced trauma life support  (ATLS) protocol.These include: A)  Airway  - Assess and protect airway and potentially the cervical spine B)  Breathing  - Maintain adequate ventilation and oxygenation C) Circulation - Assess for and control bleeding to maintain organ perfusion including  focused assessment with sonography for trauma (FAST) D) Disability - Perform basic neurological exam including  Glasgow Coma Scale (GCS) E) Exposure - Expose entire body and search for any missed injuries, entry points, and exit points while maintaining body temperature Depending on the extent of injury, management can range from urgent surgical intervention to observation. As such, any history from the scene such as gun type, shots fired, shot direction and distance, blood loss on scene, and pre-hospital vitals signs can be very helpful in directing management. Unstable people with signs of bleeding that cannot be controlled during the initial evaluation require immediate  surgical exploration  in the operating room .  Otherwise, management protocols are generally dictated by anatomic entry point and anticipated trajectory.

8. Abdomen Important anatomy in the abdomen includes the  stomach ,  small bowel ,  colon ,  liver ,  spleen ,  pancreas ,  kidneys , spine, diaphragm, descending aorta, and other abdominal vessels and nerves. Gunshots to the abdomen can thus cause severe bleeding, release of bowel contents,  peritonitis , organ rupture, respiratory compromise, and neurological deficits. The most important initial evaluation of a gunshot wound to the abdomen is whether there is uncontrolled bleeding, inflammation of the  peritoneum , or spillage of bowel contents. If any of these are present, the person should be transferred immediately to the operating room for  laparotomy . [34]  If it is difficult to evaluate for those indications because the person is unresponsive or incomprehensible, it is up to the surgeon's discretion whether to pursue laparotomy , exploratory  laparoscopy , or alternative investigative tools.

9. Extremities The four main components of extremities are  bones ,  vessels ,  nerves , and  soft tissues . Gunshot wounds can thus cause severe bleeding,  fractures , nerve deficits, and soft tissue damage. The Mangled Extremity Severity Score (MESS) is used to classify the severity of injury and evaluates for severity of skeletal and/or soft tissue injury, limb  ischemia , shock, and age .  Depending on the extent of injury, management can range from superficial wound care to limb  amputation . Vital sign stability and vascular assessment are the most important determinants of management in extremity injuries. As with other traumatic cases, those with uncontrolled bleeding require immediate surgical intervention.If surgical intervention is not readily available and direct pressure is insufficient to control bleeding,  tourniquets  or direct clamping of visible vessels may be used temporarily to slow active bleeding.People with hard signs of vascular injury also require immediate surgical intervention. Hard signs include active bleeding, expanding or pulsatile hematoma, bruit/thrill, absent distal pulses and signs of extremity ischemia .

10. skull Skull entry wounds were most often round or oval. Unusual shapes were observed in bones such as the mandible and mastoid process, but were also found to be triangular, nearly triangular, or irregular. The expected internal beveling was obvious in all but one skull. External beveling of an entry wound was observed in only one case (parietal bone). Exit wounds were roughly round, oval, square, and rectangular, and were always more irregular than entry wounds. Understanding gunshot wound characteristics is important for interpreting distance, velocity, direction, and sometimes caliber size, and helps in reconstructing events surrounding death by gunshot. Tables, figures, references

11. Thank You For Your Attention!