Trauma

Crush Injuries

Background

1. Definition
   • Prolonged continuous pressure to a body area
     • Extremities
       • Finger(s)
       • Hand/forearm
       • Foot/lower leg
     • Abdomen/pelvis
     • Chest
       • Traumatic asphyxia
2. Synopsis
   • Management includes
     • Fluid resuscitation
     • Prevent/treat rhabdomyolysis
     • Manage compartment syndrome
     • Tetanus
     • Watch for and treat electrolyte abnormalities

Pathophysiology

1. Mechanism
   • Prolonged compression (4-6 hrs)
     • Ion influx into damaged cells causes irreversible cell death
   • Upon decompression
     • Crushed muscle absorbs large amounts of fluid
       • Fluid is third-spaced
       • Amount may be equal to total extracellular volume in 75 kg adult
     • Hypovolemic shock
     • Muscle releases myoglobin, K+, and PO4-
       • Rhabdomyolysis
         • Hyperkalemia
         • Hypocalcemia
         • Hyperuricemia
         • Acidosis
2. Etiology/Risk Factors
   • Motor vehicle accidents
   • Hurricanes
   • Building collapses
   • Mining accidents
   • Alcohol intoxication/drug overdose
   • Unresponsive patients exert prolonged pressure on a body part
   • High velocity/pressure trauma
   • Bombings, earthquakes, building collapse, mine accidents
   • Train accidents, working under cars, collapsed excavations/ditches
   • Pneumatic antishock garment (PASG)
   • Prolonged inflation times may cause compressive injuries
   • Wringer injuries
   • Industrial gears, rollers, punches, or presses
3. Epidemiology
   • Mortality/Morbidity
     • Potential development of ATN
       • Approaches 100% if hydration delayed > 6-12 hrs
       • Mortality near 40% if ARF occurs
       • Occurs rapidly once crushed areas are decompressed

Diagnostics

1. History/Symptoms
   • Often little/no pain immediately after extrication
   • Few physical complaints
   • Emotional complaints dominate history
     • Especially if patient trapped/buried for hours
   • Lack of symptoms may mislead caregivers
     • Potentially fatal
   • Pain usually begins later
2. Physical Exam/Signs
   • Skin may be relatively undamaged
     • Bullae/discoloration may be present
     • Bleeding/bruising
     • Multiple lacerations may be present
   • Edema may be minimal initially
     • Develops over hours
   • Patchy sensory deficits may be present
   • Flaccid paralysis may be present
     • Crushed muscle does not contract when pinched
     • Muscle may be non-elastic
   • Pulses may be present
     • Difficult to palpate
   • Body part may be deformed
     • Assess for fracture
3. Labs/Tests
   • CBC +Diff
   • Electrolytes, BUN/Cr
   • Myoglobin (repeat every 6 hrs)
   • Creatine phosphokinase (CK) (repeat every 12 hrs)
     • Very sensitive test for muscle damage
     • Rhabdomyolysis : > 5 times the upper level of lab reference range
4. Imaging
   • X-rays of crushed areas
   • May reveal fracture or gas in tissue
5. Differential Diagnosis
   • Spinal cord trauma
   • Status epilepticus
   • Compartment syndrome
   • Polymyositis/dermatomyositis
   • Malignant hyperthermia

Treatment

1. Initial/Prep/Goals
   1. Extrication/Pre-hospital care
      1. Patients may be saved even after > 24 hr entrapment
      2. Initial tx: prevent hypovolemia and acute renal failure
         1. Massive fluid replacement may be needed
         2. During/shortly after extrication
      3. IV NS at rate high enough to maintain adequate VOP at 200-300 mL/hr initially
   2. Emergency Dept care
      • Monitor pulse, BP, heart rhythm
      • Continue fluid resuscitation
        • Initiate (or continue) IV hydration: up to 1.5 L/hr
        • May require up to 12 L/day
      • Place urinary cath to monitor urine output
        • 0.5 mL/kg/hr minimum
      • Prevent/treat rhabdomyolysis
      • Check for compartment syndrome in crushed/swollen extremities
      • Tetanus
        • If no booster in past 10 yrs
2. Medical/Pharmaceutical
   • Hyperkalemia / Hypocalcemia
     • Calcium gluconate 10% (10 mL) or calcium chloride 10% (5 mL) IV over 2 minutes
     • Sodium bicarbonate: 1 mEq/kg IV slow push
     • Regular insulin: 5-10 U
     • D5O: 1-2 ampules IV bolus
     • Kayexalate (25-50 g) with sorbitol 20% (100 mL PO/PR)
       • Use for emergent management of hyperkalemia is trending down
       • Risk of colonic necrosis
   • Acidosis
     • Alkalinization of urine is critical
       • Administer IV sodium bicarbonate until urine pH reaches 6.5
         • Prevention of myoglobin and uric acid deposition in kidneys
   • Hyperuricemia
   • Cardiac Arrhythmias
     • Monitor for cardiac arrhythmias and cardiac arrest
       • Treat accordingly
3. Surgical/Procedural
   • HbO2 may be useful
     • Faster demarcation of necrotic tissue
     • Bactericidal/bacteriostatic
     • Anti-edema (through vasoconstriction)
     • Increases collagen synthesis
   • Be aware of high risk of infection in devitalized tissues

Disposition

1. Admission Criteria
   • Admit all, monitor closely for renal failure
2. Consult with specialties as required
   • Trauma surgery
   • Orthopedics
   • Nephrology
3. Discharge/Follow-up instructions
   • Amputation may be indicated
     • Especially crush injury with open tibial fractures

References

1. CDC. After an earthquake; management of crush injuries & crush syndrome. Available at: https://stacks.cdc.gov/view/cdc/11904. [Accessed August 2023]
2. Schwarz RB, McManus JG. Tactical Emergency Medical Support and Urban Search and Rescue. In: Marx JA, Walls RM, Hockberger RS, et al; (eds). Rosen's Emergency Medicine: Concepts and Clinical Practice. 8th ed. Philadelphia, PA:Elsevier, 2014;Chapter e4
3. Tang N, Bright L. Tactical emergency medical support and urban search and rescue. In: Walls RM, Hockberger RS, Gausche-Hill M; (eds). Rosen's Emergency Medicine: Concepts and Clinical Practice. 9th ed. Philadelphia, PA:Elsevier, 2018;Chapter e4

Contributor(s)

1. Thota, Darshan, MD, FAWM
2. Bruner, David, MD, FAAEM
3. Ballarin, Daniel, MD
4. Ho, Nghia, MD

Updated/Reviewed: August 2023