A palliative operation for the purpose of increasing pulmonary blood flow, hence systemic oxygen saturation. It involves creating an anastomosis between a subclavian artery and the ipsilateral pulmonary artery either directly with an end-to-side anastomosis (classical) or using an interposition tube graft (modified). (Blalock A, Taussig HB. The surgical treatment of malformations of the heart in which there is pulmonary stenosis or pulmonary atresia. JAMA 1945;128:189-202.)
The Blalock-Taussig shunt is a surgical procedure to give palliation to cyanotic heart defects which are common causes of blue baby syndrome. In modern surgery, this procedure is temporarily used to direct blood flow to the lungs and relieve cyanosis while the infant is waiting for corrective surgery.