PREHOSPITAL MANAGEMENT OF CRUSH INJURIES

BY CHRISTOPHER PIEPENBURG

It is a warm spring day. You and your crew have just finished eating your noon meal. You look out off the balcony of your station to see the new urban sprawl taking place within a mile of your station. As you stand there reminiscing about what that area looked like a year ago, the station tones blare out a technical rescue response, “Rescue 3, Tower and Medic 35, respond for a party trapped at the construction site at the corner of Lima and Briarwood.”

You arrive on-scene to find construction workers waving their arms and shouting near the edge of a trench. The construction foreman tells you one of his pipe layers is trapped under a 4-foot by 20-foot sewer pipe that is wedged in the trench. The worker can still talk and says he is trapped from the waist down and cannot get out.

Once the scene is safe and your plan is in place, you send one of your paramedics into the trench to assess the victim. The paramedic reports back that the victim is a 28-year-old male who, other than for pain in his legs, seems to be doing well: He is conscious, and his vital signs are within normal limits.

After four hours of breaking concrete and digging around the trapped party, your crew moves him to the medic unit and begins transport to the nearest Level 1 trauma center without incident. Care was passed off to the emergency department physician.

Later that evening, one of your paramedics calls the hospital for follow-up on the victim. The paramedic talks with the physician, who says that approximately two hours after the victim was dropped off, he developed severe hyperkalemia, went into cardiac arrest, and was pronounced dead 45 minutes after the initial arrest. On completion of the autopsy, the medical examiner found that the victim died of toxicity secondary to the his injury, also known as crush injury syndrome.

CRUSH INJURIES

Crush injuries are rarely seen in prehospital medicine but are common in times of disaster, both natural and manmade. Early and aggressive treatment of victims suspected of having a crush injury is paramount. Without aggressive prehospital treatment, the victim may die during extrication or weeks later from complications of the injury.

Pathophysiology

In the crush injury syndrome, the initial injury is at the site of the muscle crushed by the mechanical force of an object. The muscle cells die as the result of the following. First, the force of the crushing object ruptures muscle cells. Second, 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. Third, the force of the crush injury compresses large vessels, resulting in the loss of blood supply to muscle tissue.1 Muscles can normally survive circulatory ischemia for up to four hours before the cell death.2 (1) 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 (see Table 1). The longer the victim is trapped, the longer the toxins are given to build up distal to the crush site. The crushing force acts as a dam that prevents these toxins from being released into the rest of the body. Once the force is removed, the toxins are allowed to run freely throughout the body, causing a myriad of problems. Along with the release of toxins after extrication, the victim can become severely hypovolemic from the third spacing of fluid, and the rapid swelling of the injured area can cause acute compartment syndrome.


Table 1. Toxins Released by Damaged Muscle Tissue
Toxin Effects
Histamine vasodilation and bronchoconstriction
Lactic Acid metabolic acidosis and cardiac dysrhythmias
Nitric Oxide vasodilation, which worsens hypovolemic shock
Potassium hyperkalemia
Thromboplastin disseminated intravascular coagulation

Assessment

When trying to determine if a victim fits the criteria for crush injury syndrome, consider the following: involvement of a muscle mass, prolonged compression, and compromised blood circulation. For instance, entrapment of a hand is unlikely to initiate the syndrome. Most of the victims who develop crush injury syndrome have a large area of involvement, such as one or both lower extremities, and the crushing force must be present for a long time, usually more than four hours. EMS personnel should suspect crush injury syndrome under these conditions and should begin treating the victim well in advance of the extrication. It may be too late if you wait to begin treatment until after the victim is freed. The victim may do well while trapped and even after being extricated may exhibit only a few signs or symptoms (see Table 2).

Table 2. Signs and Symptoms of a Crush Injury
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.

Treatment

Prehospital treatment of a victim suspected of developing crush injury syndrome can be broken down into two parts, the pre-extrication phase and the post-extrication phase.3, 4 In the first phase, rescuer safety is the first priority. Once that has been established, treatment can begin. Initially, treatment is the same as for any other trauma victim. The airway is the priority; breathing and circulation are close behind. Establish intravenous (IV) access, preferably two large-bore (14g) lines, and replace lost fluid before extricating the victim. Normal saline is a good initial choice for fluid replacement because it does not contain extra electrolytes that can compound any toxins in the body.

Avoid fluids that contain potassium. Use special care when administering fluid to children and individuals with a history of cardiac or renal problems. Place the victim on a cardiac monitor to get a good baseline. This will allow the medic to look for early changes in the EKG once the victim is extricated.

Control pain by following local pain management protocols. Immediately prior to the release of the compression on the victim’s affected body areas, administer 1 mEq/kg of sodium bicarbonate to help alkalinize the urine and to attempt to control hyperkalemia and acidosis caused by the compression of the affected area. (3) Once the victim has been extricated, ensure that the airway, breathing, and circulation (ABCs) are still intact, and be prepared to treat for hypovolemic shock. Also, pay close attention to the cardiac monitor for signs of hyperkalemia5 (see Table 3). If the victim develops moderate to severe hyperkalemia, administer 1g calcium chloride to treat the hyperkalemia and reduce the risk of ventricular fibrillation. Also, prehospital administration of albuterol by nebulizer has been shown to promote the cellular reuptake of potassium and reverse the bronchoconstriction produced by the release of histamine from the damaged tissue. (5)


Table 3. EKG Changes in a Hyperkalemic Patient
5.5 – 6.0 mEq/L Mild condition: peaked T waves
6.1 – 7.0 mEq/L Moderate condition: prolonged PR interval, flattening of P waves,
segment elevation or depression, QRS widening
7.0 mEq/L and greater Severe condition: loss of P waves,
AV blocks, bundle branch blocks, PVCs

On arrival at the hospital, the crush-injured victim will be closely observed for signs of further toxicity, elevating intracompartmental pressure of the limb, and proper renal function, along with other injuries that may have been incurred.

After the 1999 Great Marmara earthquake in northwestern Turkey, doctors found that many of the people treated for crush injuries lived or died based on the time that elapsed before treatment was provided at an appropriate trauma care facility. Those transported to the trauma facility in the shortest time did much better because of the more immediate availability of intensive care therapy and hemodialysis.6

An example of aggressive assessment and care of a severely injured crush victim was the rescue of Salvador Peña, the driver of a street sweeper rescued from a collapsed parking structure by the Los Angeles City and County Fire Departments. Peña’s sweeper was crushed by two levels of a parking structure during the Northridge Earthquake on January 17, 1994, in Los Angeles. From the beginning of the nine-hour ordeal, a paramedic was with Peña at all times to monitor, administer oxygen, and comfort and reassure him. The tight space and limited access to Peña made it difficult for paramedics to establish IV access to provide fluid therapy. During the last hour of Peña’s ordeal, the rescuers stopped and confirmed their extrication plan and exit strategy for Peña’s removal. This allowed rescuers to have Peña removed from the vehicle and transported to a waiting helicopter within five minutes of the removal of the dash from Peña’s legs. Peña was flown to UCLA Medical Center, where he underwent treatment for his injuries, including crush syndrome. The fact that Peña is alive is a miracle in itself, but after many surgeries and intense rehab, Peña also was able to walk with assistance. If the rescuers of the LA City and County Fire Departments hadn’t treated Peña as a possible crush injury victim, he could have been the 62nd person to die as a direct result of the Northridge Earthquake.7

• • •

A severe crush injury that culminates in a crush injury syndrome can be detrimental unless aggressively and promptly treated. The main causes of death following a crush injury include hypovolemic shock, hyperkalemia, metabolic acidosis, and acute renal failure. EMS personnel play a crucial role in identifying and treating the victims of a crush injury. Aggressive and appropriate care prior to and after extrication can make an important, potentially life-saving, difference.

References

1. Dickson, J: “Crush Injury, www.mediccom.org/public/tadmat/training/NDMS/crush.pdf/.

2. Reis, N.D., O.S. Better, “Mechanical muscle-crush injury and acute muscle crushcompartment syndrome: With special reference to earthquake casualties,” The Journal of Bone and Joint Surgery (Br), www.JBJS.org.uk/current.dtl/.

3. San Francisco Emergency Medical Services: “Crush Syndrome.” www.sanfranciscoems.org/publication/Protocols/Treatmentprotocolsforspecialcircumstances/P101crushinjuryprotocol.pdf/.

4. Alameda County, California: “Crush Injury Syndrome (#7102).”www.co.alameda.ca.us/PublicHealth/organization/divisions/ems/.

5. Garth D: “Hyperkalemia,” www.emedicine.com/emerg/topic261.htm, 2005.

6. Demirkiran, O., Y. Dikmen, T. Utku, and S. Urkmez: “Crush syndrome patients after the Marmara earthquake,” http://emj.bmjjournals.com/cgi/content/full/20/3/247/.

7. Collins, L, “The Rescue of Salvador Peña,” Fire Engineering, August 1994, 99-118.

CHRISTOPHER PIEPENBURG, a member of the fire service since 1995 and a third-generation firefighter, is a firefighter/paramedic with South Metro (CO) Fire Rescue, assigned to a medic company in the Denver Tech Center. He is also a member of the department’s technical rescue team and a member of FEMA USAR CO-TF1.

GLOSSARY

  • Crush injuries. Injuries that occur when a body part is subjected to a high degree of force or pressure, usually after being squeezed between two heavy or immobile objects.
  • Third spacing of fluid. The movement of fluid from the vascular space to the interstitial space.
  • Acute compartment syndrome. A progressive, painful loss of function of muscles and nerves that happens most often in the leg or arm. It occurs when bleeding and swelling get in the way of proper blood circulation in the muscle and nerve tissues. As the tissue pressure increases, it decreases blood flow, both venous and arterial. Nerve and muscle cells start to die within four to eight hours.
  • Hyperkalemia. An abnormally high concentration of potassium ions in the blood.
  • Hypervolemic. An excessive amount of blood in the body.
  • Disseminated intravascular coagulation. A condition in which small blood clots develop throughout the bloodstream, blocking small blood vessels and depleting the platelets and clotting factors needed to control bleeding.

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