The blood of the being human typically has a reddish color (less in those rare cases of diseases related to hemoglobin), the optical properties of skin distort colored dark red deoxygenated blood to appear blue. The elemental principle behind cyanosis is that deoxygenated hemoglobin is more prone to bluish optic staining, and it also produces vasoconstriction which makes it more apparent.
The color dispersion produced by blue vein color and cyanosis is similar to the process that makes the sky appear blue: some colors refract and absorb more than others. During cyanosis, tissues have unusually low oxygen concentrations, and therefore tissues that are normally filled with bright oxygenated blood are filled with oxygenated dark blood. Dark blood is much more prone to optical effects, and therefore oxygen deficiency (hypoxia) leads to bluish discoloration of the lips and other mucous membranes.
Cyanosis is the bluish discoloration of the skin, mucous membranes and nails, generally due to the presence of concentrations equal to or greater than 5 g / dl of oxygen-free hemoglobin in blood vessels close to the surface of the skin. or pigments Hemoglobin abnormalities (methemoglobin or sulfohemoglobin) in red blood cells. Because cyanosis depends on the amount and not on a percentage of deoxygenated hemoglobin, it is much easier to find in states with a higher volume of red blood cells (polycythemia) than in cases with decreased red blood cell mass (anemia). It can be difficult to detect in patients with highly pigmented skin.
