Quick and Dirty Guide to Crush Injuries

Crush injuries occur when a crushing force is applied to a body area. Sometimes they are associated with internal organ rupture, major fractures, and hemorrhagic shock. Early aggressive treatment of patients suspected of having a crush injury is crucial. Along with the severity of soft tissue damage and fractures, a major concern of a severe crush injury is the duration of the compression/entrapment. Prolonged compression of a body region or limb may lead to a dangerous syndrome that can become fatal.  Crush Syndrome is difficult to diagnose and treat in the pre-hospital setting because of the many complex variables involved.

The variables to consider are:

• Extent of tissue involvement/damage
• Duration and force of the compression
• Patient’s position and condition
• Patient’s age and overall health
• Any associated/additional injuries

With crush injury syndrome:

The initial injury is at the site of the body/muscle crushed by a heavy object (mechanical force) .
The muscle cells begin to die, as a result of the following:

1. The force of the crushing object ruptures muscle cells.
2. The direct pressure of the object on the limb causes muscle cells to become ischemic. The combination of mechanical force and ischemia can cause muscle death within an hour.
3. The force of the crush injury compresses large vessels, resulting in the loss of blood supply to muscle tissue.
   A. Muscles can survive circulatory ischemia for up to four hours before cell death.
   B. After four hours, the cells begin to die as a result of the circulatory compromise. The damaged muscle tissue produces and releases many toxins that can have detrimental effects on the body.
   
   

                   Toxins Released by Damaged Muscle Tissue

Toxin: Histamine

Effect: Vasodilation and bronchoconstriction

Toxin: Lactic Acid

Effect: Metabolic acidosis & dysrhythmias

Toxin: Nitric Oxide Vasodilation

Effect: Worsens hypovolemic shock

Toxin: Potassium

Effect: Hyperkalemia

Toxin: Thromboplastin Disseminated

Effect: Intravascular coagulation

 

The longer the victim is trapped, the more toxins build up distally to the crush injury. The crushing forces act as a dam preventing the toxins from being released to the rest of the body. When the force is removed, the toxins are allowed to quickly flow  through the body,  causing a multitude of problems.
Along with the release of toxins after extrication, the victim can become severely hypovolemic from the third spacing of fluid.

The rapid swelling of  an injured extremity can cause acute compartment syndrome.

Assessing Potential Crush Injury Syndrome

When trying to determine if a trauma victim is suffering crush syndrome;
consider the following:

• Involvement of a muscle mass
• Prolonged compression
• Compromised blood circulation

For instance, entrapment of a hand is unlikely to initiate the syndrome. Most of the victims who develop crush injury syndrome usually exhibit with a large area of involvement, such as one or both lower extremities.

Signs and Symptoms of Crush Injury Syndrome

• Skin may be bruised and discolored, but skin can remain intact
• Swelling usually appears rapidly after pressure is released
• Pain after pressure is released; it can become excruciating
• Pulses may or may not be present

Note: EMS personnel should suspect crush injury syndrome with the above signs and symptoms. EMS should begin treating the victim well in advance of extrication. It may be too late, if you wait to begin treatment until after the victim is freed.  CS patients can remain stable without any signs/symptoms while trapped; even after being extricated, they may exhibit only a few signs or symptoms and deteriorate very rapidly.
Be Suspicious with potential crush injuries!

Compartment Syndrome

Compartment Syndrome occurs when injured tissue swells within the fascia and connective tissues inside of a limb causing an increase in the pressure within that “compartment”. It is usually not a concern for pre-hospital providers because it occurs several hours or days after the initial injury. But, it is important for the EMT to understand the possible outcome of a critically injured extremity, so the potential is not overlooked.

Here is a Quick 5 minute video explaining Compartment Syndrome

Treatment

If prolonged extrication (> 4 hrs.), treat the patient for CS/CI.
Do not wait for clinical signs to develop, as the patient may already be in renal failure with metabolic acidosis worsening.

EMT

1. Provide airway and ventilatory support (12-15 lpm O2 via NRB/BVM)

2. Maintain the patient’s body temperature

3. Treat for shock.

Paramedics:

4.  Attach EKG; monitor patient closely for hyperkalemia and other dysrhythmias.

 EKG Changes in a Hyperkalemic Patient

• Mild condition: peaked T waves
• Moderate condition: prolonged PR interval, flattening of P waves
• Segment elevation or depression, QRS widening
• Severe condition: loss of P waves, AV blocks, BB blocks, PVCs

5. Gain IV access via 2 large bore catheters (14g-16g). Aggressively hydrate the patient with D₅¹/₂ NS to manage hypovolemia and maintains kidney function/urine output.

6. Administer sodium bicarbonate to control hyperkalemia and acidosis, preventing dysrhythmias and renal failure.

Consider mannitol, (per MCP) to maintain urine output. DO NOT administer loop diuretics such as Lasix, it may acidify the urine.

7. Manage severe hyperkalemia with insulin and dextrose, (per MCP).

Calcium Chloride is generally NOT considered for hyperkalemia unless severe hyperkalemia induced dysrhythmias exist.

8. The use of arterial tourniquets before the release of a crushing injury site may be beneficial.

9. After extrication, immediate care may include transporting the patient to a facility with hyperbaric chamber capabilities in order to decrease issue necrosis and muscle edema.

A cool PP presentation on treating crush injuries!

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