Gibbon, John H., Jr.: American cardiovascular surgeon (1903-1973) who performed the world's first successful open-heart operation using a heart-lung machine that totally bypassed the heart. Research and work with cats and dogs prepared the heart-lung machine for a human subject. On May 6, 1953, Dr. Gibbon pioneered modern open-heart surgery by using the machine he designed to oxygenate the blood of Cecelia Bavolek, an 18-year-old girl, while he repaired a hole in her heart. For 27 minutes during the operation, her heart and lung functions were completely maintained by Dr. Gibbon's machine. Ms. Bavolek recovered. This type of surgery, using modern versions of Dr. Gibbon's pump oxygenator, is now commonly used in open heart surgery. His wife, Mary, was his laboratory assistant and helped him design the Gibbon heart-lung machine. See also: Kirklin, John W..