Cyanosis is best described as:

• A. Red flushed skin
• B. Blue coloration of skin and mucous membranes
• C. Yellowing of skin and eyes
• D. Pale, ashen skin

Answer: (B)

Cyanosis is a bluish discoloration of the skin and mucous membranes caused by increased levels of deoxygenated hemoglobin in the blood, usually from hypoxemia. It can be central, showing up on the lips, tongue, and mucous membranes when arterial oxygen is low, or peripheral, seen in fingers or toes when circulation is slow or exposure to cold. The description of blue coloration of the skin and mucous membranes directly matches cyanosis. Red flushed skin would indicate increased blood flow or inflammation, yellowing points to jaundice from bilirubin buildup, and pale, ashen skin suggests pallor from anemia or poor perfusion. In practice, cyanosis signals that oxygen delivery is compromised and requires prompt assessment of airway, breathing, and oxygenation.