The Blalock–Thomas–Taussig shunt (commonly called the Blalock–Taussig shunt) is a surgical procedure used to increase blood flow to the lungs in some forms of congenital heart disease. These conditions, in which a child is born with an abnormal heart include pulmonary atresia and Tetralogy of Fallot and are common causes of blue baby syndrome. The procedure involves connecting a branch of the subclavian artery or carotid artery to the pulmonary artery. In modern practice, this procedure is temporarily used to direct blood flow to the lungs and relieve cyanosis while the infant is waiting for corrective or definitive surgery. The Blalock–Thomas-Taussig shunt is used in the first step of the three stage palliation (The Norwood Procedure).