What type of shunting is characterized as cyanotic?

Cyanotic shunting is primarily associated with right to left shunting. This occurs when deoxygenated blood bypasses the lungs and enters the systemic circulation directly. As a result, there is a mixture of oxygen-poor blood with oxygen-rich blood, leading to decreased overall oxygen saturation in the body. This results in the clinical manifestation of cyanosis, which is a bluish discoloration of the skin and mucous membranes due to lack of adequate oxygenation.

In contrast, left to right shunting typically causes an increase in blood flow to the lungs and may lead to symptoms associated with increased pulmonary circulation, rather than cyanosis. Acyanotic shunting also refers to left to right shunts where oxygen saturation in systemic circulation is usually maintained, and no cyanotic symptoms are present. Obstructive shunting involves blockages that affect blood flow, but it does not directly lead to the characteristic cyanosis found in right to left shunting scenarios. Therefore, right to left shunting is the clear choice when identifying shunting that results in cyanosis.