Dr. William Mustard was a Canadian pioneer in cardiac surgery. In the 1950s, he proposed a revolutionary idea: performing heart surgery without stopping bloodBlood is composed of red blood cells, white blood cells, platelets, and plasma. Red blood cells are responsible for transporting oxygen and carbon dioxide. White blood cells make up our immune defense system. Platelets contribute to blood circulation, using a machine and monkey lungs to oxygenate bloodBlood is composed of red blood cells, white blood cells, platelets, and plasma. Red blood cells are responsible for transporting oxygen and carbon dioxide. White blood cells make up our immune defense system. Platelets contribute to blood outside the body. Although the early results were tragic, his innovation paved the way for major advances in modern cardiac surgery.