Brady is pleased to share excerpts of its EMS Transition Series. Transition Series: Topics for the EMT by Joseph Mistovich and Daniel Limmer provides both an overview of new information contained within the National EMS Education Standards at the EMT level and a source of continuing education for practicing EMTs. Intended for a new generation of EMTs, the text integrates new “topics” that were not contained in the U.S. DOT 1994 EMT-Basic National Standard Curriculum and existing “topics” at a much greater depth and breadth than what was contained in the typical EMT-Basic education program. Visit www.bradybooks.com for more information.
Crush injuries and compartment syndrome damage tissues in a very specific way. Crush injury is a form of blunt trauma, whereas compartment syndrome is a complication of blunt trauma. These particular types of injury present the EMT with very specific challenges to patient assessment and care. Compartment syndrome requires an EMT to think long term and prevent ongoing injury, whereas crush injuries force the EMT to consider some very different treatment modalities. In this topic we discuss both of these specific circumstances as they pertain to blunt trauma.
Even with these specific circumstances in mind, you should remember the basic principles of assessing and treating blunt force trauma. In particular, recall that when dealing with soft tissue injuries you must consider not just the outside of the skin but also the potential for injury beneath the skin.
Blunt trauma damages by applying force and stretching tissues beyond their normal tolerances. A crush injury—a particular type of blunt trauma—damages tissues by compressive force (see Figure 1). This force is generally applied over larger areas and damages more tissue, either through direct compression (direct, crushing force) or by compressing tissues and limiting blood flow (perfusion) to the cells in that area. Crush injuries can occur over a relatively small area, such as striking the thumb with a hammer, or over a large area, such as traumatic asphyxia of the chest. The mechanism of injury remains similar.
This type of injury can occur from either external or internal forces. An example of external direct compression might be a beam that has fallen and trapped a patient’s leg. A different mechanism that might have a similar net effect would be compartment syndrome. In compartment syndrome, internal swelling causes high pressure to build up within the relatively closed muscular compartment of an extremity. This pressure can damage nerve, muscle, and vascular tissue and limit perfusion to that area. As compartment syndrome emerges, tissue is destroyed just as it would be by direct force.
The broad definition of soft tissue injury (non-bony, non-organ injury) accounts for the vast majority of traumatic injuries. Crush injuries are only a small portion of this category, but they result from a wide range of mechanisms.
Direct force crush injuries are the most common types of crush injuries. In this case, an object (or objects) applies force and destroys tissue by direct compression. Examples of this include injuries caused by falling objects and blunt trauma distributed over larger areas.
In this situation, compression of tissue is caused by the patient’s position. This damage typically manifests over hours—and sometimes days. The inability of a patient to shift position causes compression and restricts blood flow. Cells are deprived of oxygen, and waste products build up. Dramatic examples of this include victims trapped and pinned by earthquakes and bomb blasts, but more common examples occur in patients who fall and are unable to get up; their weight causes the crushing force on dependent structures.
Consider a stroke patient who collapses and pins her own leg beneath her body weight (see Figure 2). Her stroke renders her unable to get up or even change her position. Her own body weight compresses her leg and causes a crush-type injury.