While doing research into the nature of hemorrhagic shock, Blalock found that surgical shock results primarily from blood loss. His recommendation that blood plasma and whole blood products be administered to those suffering from shock saved many lives during WWII. His later work on “blue baby syndrome,” formally known as Tetralogy of Fallot (TOF), led to the development of the Blalock-Taussig shunt, a pioneering procedure in the field of pediatric cardiology. What makes TOF patients “blue”? Discuss