Crush Injury

Last updated 12/08/19

Definition

Localised tissue injury from compressive forces which may be rapidly fatal on release of trapped body part

Features

Development is time and pressure dependant
Severity of response related to bulk of muscle effected
More common in cival wars and natural disasters
Crush syndrome

Systemic response related to widespread ischaemia and necrosis of soft tissue
Typically seen after 4-6hrs of reduced perfusion from crush injury

In severe cases may be seen in 60 minuntes

Leaky sarcolemma membrane in muscle cells
Accumulation of tissue breakdown products/toxins in trapped/crushed body part

Most notably myoglobin and potassium

On release of crush these toxins are released into the systemic circulation and may be rapidly fatal

Causes

Earthquakes: common cause of mortality (rhabdomyloysis)
Motor Vehicle Accident (MVA)
Mining accidents
Has been described after stroke and intoxication/overdose (from patients own body weight and long lie)

Associated Signs & Symptoms

Pain
Typically an entrapped limb in traumatic cases

Risk Factors

Severe trauma

Complications

Hypovolaemia: histamine release, intracellular oedema and other toxins
Hyperkalaemia
Rhabdomyolysis: hypermyoglobinaemia
Metabolic acidosis (lactic): lactate, hyperkalaemia
Acute Kidney Injury (AKI): hypovolaemia, metabolic acidosis, rhabdomyolysis
Disseminated Intravascular Coagulation (DIC): thrombolastin release from damaged tissues
Compartment syndrome
Haemorrhage
Cardiac arrest: typically post release of crush: hyperkalaeamia, hypovolaemia, metabolic acidosis

Differential Diagnosis

Heat stroke
Associated trauma

Investigations

Vitals

BP: hypotension: shock

Haemorrhage
Intravascular volume depletion from damaged tissue oedema

Temp: maintain normothermia in context of trauma

ECG

Hyperkalaemia: peaked T waves, prolongd PR, wide QRS

Bradycardia, Ventricular Tachycardia (VT), Ventricular Fibrillation (VF)

Blood gas (ABG/VBG): metabolic acidosis
Lactate: lactic acidosis
FBE: Hb: haemorrhage
U&E

K+: hyperkalaemia
Renal function: AKI, rhabdomyolysis

CK: elevated: rhabdomyolysis
Coagulation studies: DIC
Imaging as indicated
Urine output: AKI

Management

Prehospital Management

Ensure secene safety

May require stabilisation prior to access

Prior to extrication (if required)

Primary survey

Address haemorrhage
Airway management as able

Assess GCS

Consider spinal precautions
O2 if safe
Mange other injuries as able

IV access/Intraosseous (IO)
Fluid load 1-2L saline 0.9%

Avoid CSL due to potassium content
If unable to administer fluids prior: tourniquet, extricate, secure access, give fluids, then remove tourniquet
Then 1-1.5L per hour maintenance
Redcuces hypovolaemia and shock on extrication

Analgesia: Ketamine &/or Fentanyl IV/IO/intranasal
Prepare in anticipation for shock and hyperkalaemia on extrication

Tourniquet on proximally - partly engaged

Extrication

Adequate analgesia

Ketamine may facilitate painful extraction

If significant delay, imminent danger or severe entrapment consider amputation

May prevent crush syndrome

Monitor

ECG for arrythmias and signs of hyperkalaemia
BP for shock

Assess and manage crushed limb

Haemorrhage control

Bandaging etc. (Israel bandage)
Tourniquet

Splinting
Analgesia/nerve block

+/- IDC for fluid balance

In-Hospital Management

Primary, secondary and tertiary surveys
Management of complications
Ongoing fluid resuscitaton 1-1.5L/hr
+/- Antibiotics
May require ICU admission + dialysis
+/- Urinary alkalination with sodium bicarbonate to prevent AKI

Target urine pH >6.5

+/- Mannitol 1-2g/kg in 20% solution for solute diuresis

Target 300ml/hr urine output

+/- Arterial line
+/- Central Venous Catheter (CVC)
+/- Tetanus immunisation

References