MODEL RELEASED. Heart surgery. Image 6 of 24. Surgeon attaching a patient to a heart-lung machine during heart surgery. A metal retractor is keeping the chest open. The tubes will join the patient's arteries and veins to the heart-lung machine, which maintains the patient's circulation while the heart is temporarily stopped. The surgeon is wearing magnifying lenses over his glasses. The heart is being prepared for heart valve replacement surgery. For a sequence showing the operation, see images M560/494 to M560/517.