MODEL RELEASED. Heart surgery. View of a surgical team conducting open heart surgery in an operating theatre. They are wearing surgical caps, gowns and face masks to maintain a sterile environment. During open heart surgery the heart must be stopped, so a heart-lung machine is needed. Tubes (not seen) carry deoxygenated blood from the patient's main veins into the heart-lung machine. In the machine, the blood is oxygenated, warmed, and pumped back into the patient's aortic artery. Heart surgery is conducted to treat defective heart valves, in cases of heart transplant, or to carry out coronary bypasses.