Cyanosis

Definition

Cyanosis is a bluish discoloration of the skin, lips, and mucous membranes caused by increased amounts of deoxygenated hemoglobin (>5 g/dL) in the blood. It is a LATE sign of hypoxia.

Types

• Central cyanosis: Oral mucosa, lips, tongue. Indicates impaired gas exchange or right-to-left shunt.
• Peripheral cyanosis: Fingertips, toes, often due to vasoconstriction or poor perfusion from shock or cold.
• Acrocyanosis: Bluish extremities in newborns. Normal for first 24 to 48 hours.

Causes

Respiratory failure, pulmonary embolism, congenital heart disease (tetralogy of Fallot), shock, hypothermia, polycythemia, methemoglobinemia.

Nursing Considerations

Cyanosis = emergency. Administer high-flow oxygen (unless COPD, titrate to 88 to 92%), assess airway and breathing, reposition, support circulation, and prepare for advanced interventions. Remember earlier signs of hypoxia are restlessness and confusion. Do not wait for cyanosis.

NCLEX Relevance

Cyanosis is a LATE sign; early hypoxia presents as restlessness, anxiety, or confusion.