ObjectivesDiscuss some basic principles of ballistics and
tissue injury
Review basic management principles for extremity gunshot wounds In the field and definitive care
Factors in Tissue Injury
K = mv 2
2E K= Kinetic Energym= massV= velocity
Caliber Inside diameter of the barrel of the gun
Expressed in hundredths of inches Ex:
.38 caliber .22 caliber
Caliber Matters?
12 G .45 .38 .32 .22
Mass Matters
Weight12-15 g 250-350
8.7 – 10.2 g 230-400
1.7-1.9 g 250-350
Velocity (m/s)
Cavitation
Formation and then immediate implosion of cavities in a liquid that are the consequence of forces acting upon the liquid.
Fackler ML.Ballistic injury. Ann Emerg Med. 1986 Dec;15(12):1451-5
FragmentationTissue injury also proportional to the cross
sectional area of the missile
.38
Fackler ML.Ballistic injury. Ann Emerg Med. 1986 Dec;15(12):1451-5
.357
Fackler ML.Ballistic injury. Ann Emerg Med. 1986 Dec;15(12):1451-5
.22 Long Rifle
.306 Long Rifle
12 G Shotgun
Management of gunshot wounds to
the extremities
Hemorrhage Control in the Field
Direct pressure or compression dressings preferred and often successful
Avoid “clamping”
Consider the use of a tourniquet
Tourniquets
TourniquetsUse of tourniquets to control hemorrhage has
been documented as early as the 17th century
Advances and uses of tourniquets described by Joseph Lister and Harvey Cushing (among others)
TourniquetsUse became discouraged after WWI following
attention to complications (nerve damage, amputations, etc.)
More recent experience in Middle East conflicts has suggested a benefit with selected use 2006 Kragh et. al. prospective study from
Baghdad. 90% vs. 10% survival rate among tourniquet use in the presence of shock; 11% vs. 24% mortality for tourniquets placed in the field compared to ER.
Extremity GSWs in the ER- Priorities
• Overall patient condition (identification and treatment of shock)
• Identification of vascular injuries/control of hemorrhage
• Identification of orthopedic injuries
• Identification of nervous injuries
• Management of soft tissue injuries
“Hard Signs” of Vascular Injury
Active/pulsatile hemorrhage
Expanding hematoma
Pulse deficit
Palpable thrill/bruit
“Soft Signs” of Vascular Injury
Hematoma
History of significant blood loss
Proximity to major vessels
Incidence of arterial injury is 2-25%
Arterial Pressure Index (API)
Blood pressure ratio of lower to upper extremity
> 0.9 considered normal
Caution if pre-existing PVD
Physical ExamPhysical Exam
Hard Signs?Hard Signs?
Yes No
OR for Exploration
OR for Exploration
Soft Signs?Soft Signs?
Yes No
APIAPI
< 0.9< 0.9Imaging (CTA)Imaging (CTA)
ObservationObservation
NoYes
Injury?Injury?
Yes
No
Complex Extremity Trauma
Combined soft tissue, osseous, vascular/nerve injuries
More common with high energy weaponry (assault rifles, etc. ) or close range shotgun wounds
Risk Factors for Amputation
Gustilo III-C injuries
Prolonged ischemia (>4-6 hours)
Destructive soft tissue injury
Multiple/severely comminuted fractures/segmental bone loss
Old age/severe comorbidity
Lower vs. upper extremity
Failed revascularization
Vascular ShuntingDefinitive vascular repair takes time
Temporary solution to restore flow
Indications: HD instability/coagulopathy/acidosis/hypothermia Unstable skeleton Major wound contamination/infection or soft
tissue deficit Austere environment Poly-trauma with other life threatening injuries
Nerve Related InjuriesMay be caused by concussion zone of blast
injury (neuropraxic/contusion injuries) Will recover spontaneously
Progressive deficits may indicate an expanding hematoma or pseudoaneurysm Decompression/resection can reverse deficit
Nerve Related InjuriesDelayed operative intervention for neurologic
deficit most often favored Allows time for spontaneous recovery of
contusion injuries Allows determination of the the full extent of
injury (prevents inadequate debridement) Surrounding contusion can lead to epineural
softening and suture failure
Nerve Related Injuries If early exploration is indicated for other
reasons (i.e. vascular), nerve exploration is warranted in stable patients with deficits Primary repair for clean/sharp transections (rare
with GSWs) Nerve ends can be tacked to fascia to prevent
retraction Ends tagged or clipped for later identification
Case #1 24 year old man
“Minding his own business” when shot in the right upper ext
HD stable
Single GSW outer mid portion of upper arm
Clear radial pulse deficit
Grossly neurologically intact
Case #241 year old man shot during attempted robbery
HD stable
2 GSWs anterior/posterior right upper thigh (presumed entrace/exit)
Palpable left pedal pulses; Dopplerable right pedal pulses; ABI 0.2
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