If I were to say to you, “I’m your perfusionist and I’ll be running the heart lung machine for your operation tomorrow. After you go to sleep. the surgeon is going to put a couple of tubes into your heart about the diameter of a garden hose. Blood arriving at your heart, instead of going to your lungs, will do a detour down that tube to the heart lung machine. I’ll pump that blood through an artificial lung and some filters back to the aorta—the artery downstream from your heart. I’ll be taking over the function of your heart and lungs with the machine while we stop your heart and turn off your lungs for an hour or two so the surgeon can sort out those blocked coronaries and fix up that valve. In essence I’ll be your heart and lungs while you’re sleep.” What would be your likely thought process? Perhaps avoidance of a disaster would figure high on the list. Cardiopulmonary bypass (CPB) is an exacting discipline (1). It is a planned life support intervention using an artificial circuit controlled by the perfusionist to replicate the function of the heart during a prolonged period of induced cardiac and respiratory arrest. This is not free of immediate significant risk to the patient.