Perfusionists are members of an open heart surgical team. A perfusionist operates extracorporeal circulation and autotransfusion equipment during any medical situation including the circulation of blood during open-heart surgery, where it is necessary to support or temporarily replace the patient?s circulatory or respiratory function. They use a number of highly technical, mechanical and electronic devices to ensure that oxygen reaches a patients body through the blood, even when the patients? lungs and heart are temporarily not functioning. A license is required to practice perfusion in the State of Texas.