Cyanosis

Bluene of the skin due to insufficient oxygenation of the blood. It may be the result of suffocation, drowning, or of any cause which interferes with a sufficient supply of air. In infants it is often caused by abnormal connection of the venous system with the aorta, which allows the pa age of unaerated blood (always of a dark blue color) into the arteries. This defect may continue through life and the individual always be of a dusky hue, especially after exercising.