Being “on bypass” refers to the use of a heart-lung machine during open-heart surgery, a critical step that allows surgeons to operate on a still heart. While on bypass, the machine temporarily takes over the functions of the heart and lungs, circulating oxygen-rich blood throughout the body. This gives surgeons a stable, blood-free field to repair or replace heart valves, perform bypass grafts, or correct other cardiac issues. Although patients are carefully monitored and fully supported by the