- Gunshot and blast wounds are increasingly seen in civilian practice
- Military and civilian wounds however differ in several key respects
- Military wounds are often heavily contaminated with delays in treatment
- The same principals apply to their treatment
Physical properties
- Penetrating missiles include both munition fragments and bullets
- Often divided into 'high' and 'low' velocity
- Velocity per se is not important
- The amount of kinetic energy transferred to tissues is they key factor
- Kinetic energy transfer depends on:
- Velocity
- Presenting area of fragment
- Mechanical properties of tissue
Fragment injuries
- Fragments are usually small and numerous
- Are of low velocity (100 - 500 m/s) and low energy (10-100 J)
- They have poor tissue penetration
- Injuries often numerous but are usually limited to fragment track
Bullet wounds
- Hand gun bullets are of low velocity (<250 m/s) and low energy (200-300 J)
- Rifle bullets are high velocity (750-1000 m/s) and high energy (2-3 kJ)
- Physiological effects depend on degree of energy transfer
- High velocity bullets can result in low energy transfer wounds
Pathophysiology
- The effects of bullets can result from both direct and indirect effects
- In low energy transfer wounds injury results from direct effects along bullet track
- In high energy transfer wounds indirect effects are more important
- Radial forces perpendicular to tract result in cavitation
- Generates contusions and lacerations away from tract
- Negative pressure within cavity can suck in environmental contaminants
- Rifle bullets also tumble (yaw) within the wound
- Increases presenting area and increases energy transfer
- Can result in small entry and exit wounds but large wound cavity
- Radial energy transfer can cause indirect fractures
- Bullet and bone fragmentation can cause secondary tracts and further unpredictable damage
Treatment
- In military environment the standard treatment of gunshot wounds has involved.
- Wound debridement
- Wound excision
- Antibiotic prophylaxis
- Dressing change and delayed primary suture at 5 days
- Similar wound management protocols have been advocated by the Red Cross
- Approach may be modified in civilian environment
Bibliography
Cooper G J, Ryan J. Interaction
of penetrating missiles with tissues: some common misapprehensions
and implications for wound management. Br J Surg 1990;
77: 606-610.
Coupland R M. Technical aspects of war wound excision. Br J Surg 1989; 76:
663-667.
Ryan J M, Milner S M, Cooper G J,
Haywood I R. Field surgery on a future conventional
battlefield: strategy and wound management. Ann R Coll Surg Eng
1991; 73: 13-20.
Saadia R, Schein M. Debridement
of gunshot wounds: semantics and surgery.
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