Which statement about crush syndrome is correct?

• A. With crush syndrome, massive blood vessel damage occurs following severe soft-tissue injuries, such as amputation of an extremity.
• B. Compromised arterial blood flow leads to crush syndrome and can occur when an area of the body is trapped for longer than 4 hours.
• C. Provided that a patient with a crush injury is freed from entrapment within 6 hours, the amount of tissue damaged is generally minimal.
• D. Tissue damage that occurs in crush syndrome is severe, but kidney injury is unlikely because toxins are quickly eliminated from the body.

Answer: (B)

Crush syndrome happens when a body part is trapped under pressure long enough to cut off arterial blood flow, causing muscle tissue to become ischemic. When the part is freed, the damaged muscle releases large amounts of potassium, phosphate, myoglobin, and other intracellular substances into the bloodstream. This surge can trigger dangerous electrolyte abnormalities, rhabdomyolysis, and potential kidney injury. The statement that best reflects this is that compromised arterial blood flow during entrapment leads to crush syndrome, and the risk increases when the area remains trapped for several hours, commonly cited as longer than about four hours.

This fits because the problem stems from ischemia due to compression, not from direct massive vascular injury. Tissue damage can be substantial even if the patient is freed within six hours, so minimal damage is not guaranteed. Kidney injury is a real concern from myoglobin and pigment release, not unlikely to occur.