Which finding is most directly used to assess peripheral perfusion?

• A. Capillary refill
• B. ECG rhythm
• C. Blood urea nitrogen
• D. Visual skin color alone

Answer: (A)

Evaluating peripheral perfusion relies on a rapid bedside indicator of how well blood is reaching the extremities. Capillary refill tests how quickly color returns to a blanched nail bed after brief pressure, directly reflecting microvascular blood flow to the periphery. Normally this refill is under about 2 seconds; delays suggest reduced peripheral perfusion and possible shock or vasoconstriction. The other choices do not measure peripheral perfusion directly: ECG rhythm assesses cardiac electrical activity; blood urea nitrogen is a lab value reflecting kidney function and volume status but not real-time peripheral blood flow; visual skin color alone is subjective and can be misleading, not providing a timing measure of blood return.