Perfusionists are trained to operate heart-lung machines during open-heart surgery. In addition, perfusionists often operate ancillary devices such as the cell saver machine intra-aortic balloon pump. The entry requirements and degree training for perfusionists are varied. In addition to satisfying prerequisite science courses, some perfusion programs require students to have between 60 and 80 credit hours of coursework before beginning their training. Others require applicants to have a bachelor’s degree or a combination of formal education in health science and practical work experience.