- 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
Abdominal stab wounds
- Abdominal stab wounds cause less trauma than gunshot wounds
- Therefore associated morbidity and mortality is reduced
- The upper abdomen is most commonly involved, particularly the left
upper quadrant
- Peritoneal violation occurs in up 70% of abdominal stab wounds
- Only half of those with peritoneal violation sustain an
intra-abdominal injury requiring operative intervention
- The liver and small bowel are the commonest organs injured
- Multiple stab wounds are present in up to 20% of patients and 10% of
abdominal stab wounds enter the chest
- Potential intra-thoracic injuries include pneumothorax and
pericardial tamponade
Clinical features
- Assessment should gain knowledge of the implement used, its site of
entry and likely track
- Examination should look for signs of evisceration, haemorrhage and
peritonitis
- Digital exploration or probing of the wound will determine whether
the peritoneum has been breached
- A plain abdominal x-ray may show signs of free gas but this
investigation has limited sensitivity
- Abdominal CT is better at assessing peritoneal penetration and the
extent of intra-abdominal injury
Management
- In the past surgical dictum mandated exploratory laparotomy for all
patients with abdominal stab wounds
- New diagnostic techniques have rendered such a dogmatic approach
obsolete
- Imaging has reduced the number of non-therapeutic laparotomies
- Evisceration, hypovolaemia and peritonitis are indications for a
laparotomy without the need for extensive investigation
- If the penetrating object is still in-situ, it should remain so
until after induction of anaesthesia
- If there are no clinical or radiological signs of bleeding or
visceral perforation then most abdominal stab wounds can be managed
conservatively
- Patients should be actively observed for 24-48 hours
Bibliography
Como J J, Bokhari F, Chiu W C et al. Practical
management guidelines for the selective non-operative management of
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721-733
DePalma R G, Burris D G, Champion H R et al.
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1335-1342.
Inaba K, Demetriades D. The nonoperative management of
penetrating of penetrating abdominal trauma. Adv Surg 2007;
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Saadia R, Schein M.
Debridement of gunshot wounds:
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