refers to the bluish coloration of the
Skin due to the presence of deoxygenated
Hemoglobin in
Blood Vessel s near the skin surface.
It can occur in the
Finger s, including underneath the
Fingernails , as well as other extremities (called ''peripheral cyanosis''), or in the
Lip s and face (''central cyanosis'').
Central cyanosis suggests a circulatory or ventilatory problem that leads to poorer blood
Oxygenation in the lungs or greater oxygen extraction due to slowing down of blood circulation in the skin's blood vessels.
Acute cyanosis can be a result of asphyxiation or choking, and is one of the surest signs that respiration is being blocked.
The elementary principle behind cyanosis is that oxygenated
Hemoglobin is red, while deoxygenated hemoglobin is blue. Thus oxygen deficiency -
Hypoxia - leads to blue discoloration of the lips and other
Mucus Membranes .
Peripheral cyanosis suggests that there is poor
Circulation in the small
Vessel s involved, such as when a person's
Hand s are very cold. However, this condition can also be permanent even in normal temperatures; see
Acrocyanosis .
