Crushing injuries that are not immediately fatal can still kill as organs fail and concentrations of toxic substances are released into the bloodstream. Since this may occur many hours after the accident, individuals who suffer crushing injuries require prompt treatment and extensive monitoring. EMS crews, nurses, and emergency room physicians have a duty of care to thoroughly assess patients for injuries along the crush spectrum and apply the appropriate treatments before fatal events can occur.
Crush injuries are part of a larger spectrum that includes four different classifications.
Crush injuries are caused as the result of physical crushing of muscles or muscle groups. These injuries often occur following prolonged compression by a heavy object, such as when an individual is pinned between motor vehicles or trapped beneath falling debris, machinery, heavy boxes, etc.
Crush syndrome is known as rhabdomyolysis. This occurs when injuries to the skeletal muscles are so severe that the injury disrupts the cellular integrity within the muscle. This disruption releases the contents of the muscles into the bloodstream.
Compression syndrome is an indirect injury to the muscles. This is caused by a slow compression of multiple muscles that causes an ischaemic injury similar to rhabdomyolysis that releases toxic substances into the bloodstream.
Compartment syndrome occurs when a rapid rise of tension takes place within a localized group of muscles. This disturbs the metabolic balance within the affected muscle group and often results in rhabdomyolysis.
Signs and Symptoms of Crush Syndrome
There are many visible signs of crush syndrome that should raise red flags for EMS crews and emergency room physicians. These include hypothermia, skin swelling, paralysis, paresthesia, decreased pulse, and changes in skin color.
Diagnostic testing can identify cardiomyopathy, renal failure, metabolic acidosis or lactic acidosis, as well as myoglobinuria, renal failure, and cardiac instability.
Head Injuries and Crush Syndrome
Approximately 80% of individuals who suffer a crushing head injury die due to asphyxiation, loss of blood, or severe trauma to brain tissue. Of the remaining 20% who survive, approximately 10% recover, while 10% develop crush syndrome.
When crushing injuries occur, they cause extensive changes to the metabolic functions of muscles. The injury causes muscle cells to release myoglobin which is converted into methmyloglobin and then into acid haematin. These are also mixed with potassium, magnesium, phosphate, and enzymes including phosphokinase and lactate dehydrogenase.
In and of themselves, these substances are not toxic. Indeed, they are essential for their role in regulating cell function. However, when crushing injuries occur, these substances are released into the bloodstream in significant quantities. The sudden or prolonged inrush of these substances can damage cells and essentially make the blood toxic.
Moreover, many crush injuries also release significant amounts of sodium and calcium. This increases muscle tension and vasodilatation restrict blood flow within the muscles and the bloodstream.
When this occurs, a patient’s organs will begin to fail. The body’s cells won’t receive the oxygen required, and the individual is at significant risk of suffocating even when the respiratory system suffered no direct injury during the crushing event.
Prompt Treatment is Essential for Survival
Prompt and proper treatment is essential for individuals who suffer a crushing event. This includes thorough testing and monitoring for at least one full day post- accident. That’s because symptoms of toxic release into the bloodstream may not be apparent for 12 hours or more after the event. EMS crews and emergency room physicians should pay particular attention to the patient’s resting pain and pain with movement, the color of their skin, and paresthesia.
Because of this, proactive treatment is advisable anytime a patient is suspected of suffering a crush injury. This includes fluid resuscitation using saline and the administration of bicarbonate, lactate, and oral citrate. Individuals undergoing treatment should be closely monitored for any signs of kidney, liver, heart, or lung failure. Kidney failure is the most common and it’s estimated that between 4 to 33% of patients who suffer a crushing injury will also suffer severe renal injury.
Prompt treatment may also involve the amputation of a severely damaged limb. In cases where the muscles and blood vessels suffer severe damage, saving the limb may cost the patient their life. By removing the limb, surgeons can remove the source of the toxins that are poisoning the blood and impairing organ function. The sooner the limb is removed, the better the prognosis for recovery.
In all cases, survival following a crushing injury often depends on whether doctors take a proactive or a “wait and see” approach. Those patients who receive a prompt and proactive treatment regimen have a greater likelihood of survival than those who receive treatment only after visible symptoms manifest and crush syndrome is diagnosed. By then, the damage has radiated throughout the body and because multiple organ systems and muscle groups are involved treatment may not be effective.