When Dr. Abe DeAnda trained in cardiac surgery years ago, he was given some dangerous advice. “There were a lot of old rules of thumb such as, ‘If you need to give one (unit of blood), give two,’” recalled DeAnda, who is now professor and chief of cardiovascular and thoracic surgery at UTMB. “Every resident memorized that about blood transfusions. It was probably the most dangerous rule you could learn in medicine.”