Which of the following is a common sign of hypoxemia?

• A. Nausea
• B. Hair loss
• C. Rash
• D. Cyanosis

Answer: (D)

Cyanosis appears when arterial oxygen is low because hemoglobin carries less oxygen and more is in the deoxygenated form, which has a bluish color that can be seen in the skin and mucous membranes. This makes it a common and classic sign of hypoxemia, especially when oxygen levels are sufficiently reduced to alter the color of blood in visible areas like the lips, tongue, and nail beds. Keep in mind it may not be obvious in mild hypoxemia, in people with darker skin, or under poor lighting, and other signs such as increased breathing or heart rate may come first. The other options listed aren’t typical signs of hypoxemia.