what is blue blood baby?

Blue baby syndrome (or simply, blue baby) is a layman's term used to describe newborns with cyanotic conditions, such as

Cyanotic heart defects
Tetralogy of Fallot
Dextro-Transposition of the great arteries
Hypoplastic left heart syndrome
Methemoglobinemia
Respiratory distress syndrome
On November 29, 1944, the Johns Hopkins Hospital was the first to successfully perform an operation to relieve this syndrome. The syndrome was brought to the attention of surgeon Alfred Blalock and his laboratory assistant Vivien Thomas in 1943 by pediatric cardiologist Helen Taussig, who had treated hundreds of children with Tetralogy of Fallot in her work at Hopkins' Harriet Lane Home for Invalid Children. The two men adapted a surgical procedure they had earlier developed for another purpose, involving the anastomosis, or joining, of the subclavian artery to the pulmonary artery, which allowed the blood another chance to become oxygenated. The procedure became known as the Blalock-Taussig shunt, although in recent years the contribution of Vivien Thomas, both experimentally and clinically, has been widely acknowledged.