Last Reviewed : 12/24/2020

Cyanosis is the appearance of a blue or purple coloration of the skin or mucous membranes due to the tissues near the skin surface having low oxygen saturation. Based on Lundsgaard and Van Slyke's work, it is classically described as occurring if 5.0 g/dL of deoxyhemoglobin or greater is present. This was based on an "estimate" of capillary saturation based on a mean of arterial versus peripheral venous blood gas measurements. Since estimation of hypoxia is usually now based either on arterial blood gas measurement or pulse oximetry, this is probably an overestimate, with evidence that levels of 2.0 g/dL of deoxyhemoglobin may reliably produce cyanosis. Since, however, the presence of cyanosis is dependent upon there being an absolute quantity of deoxyhemoglobin, the bluish color is more readily apparent in those with high hemoglobin counts than it is with those with anemia. Also the bluer color is more difficult to detect on deeply pigmented skin. When signs of cyanosis first appear, such as on the lips or fingers, intervention should be made within 3–5 minutes because a severe hypoxia or severe circulatory failure may have induced the cyanosis.

The name cyanosis literally means "the blue disease" or "the blue condition". It is derived from the color cyan, which comes fromkyanós, the Greek word for "blue".


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Basic information: medline plus skin discoloration - bluish news medical what is cyanosis? health line peripheral cyanosis nhs uk blue skin and lips (cyanosis) health grades what is cyanosis? about kids health cyanosis merck manuals (consumer version) cyanosis university of maryland medical center cyanotic heart disease very well what is cyanosis?


Advanced information: patient cyanosis medscape cyanosis cyanosis in newborns radiopedia cyanotic congenital heart disease management of cyanotic patients epocrates online evaluation of cyanosis in the newborn emdocs cyanosis



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