Cyanosis is defined as which of the following?

• A. Redness of skin
• B. Bluish tinge to skin
• C. Loss of hair
• D. Yellowing of skin

Answer: (B)

Cyanosis is a bluish discoloration of the skin and mucous membranes caused by an increased amount of deoxygenated hemoglobin in circulating blood. When oxygen levels are low or oxygen delivery is impaired, hemoglobin carries less oxygen, and the deoxygenated form gives a blue tint that is often visible in areas where vessels are close to the surface, like the lips, nail beds, and mucous membranes. The other options describe redness, hair loss, or yellowing, which are not cyanosis. Recognizing cyanosis points to potential hypoxemia or poor oxygen delivery and requires assessing breathing and circulation and addressing oxygenation.