Which of the following is NOT a conduit used for cardiopulmonary bypass?

The correct answer is the ulnar artery, as it is not commonly used as a conduit for cardiopulmonary bypass procedures. In the context of cardiopulmonary bypass (CPB), conduits are typically selected based on their ability to provide adequate blood flow and support surgical interventions.

The internal mammary artery is often utilized due to its favorable characteristics, such as its proximity to the heart and its rich blood supply, which makes it a good choice for bypass grafting, especially in coronary artery bypass grafting (CABG).

The radial artery is also frequently used as a graft for arterial bypass in patients with coronary artery disease. Its accessibility and ability to provide a good arterial inflow make it a valuable conduit.

The great saphenous vein is a common venous conduit used during bypass surgery, particularly in CABG, for its length and adequate vein diameter, facilitating effective grafting.

In contrast, the ulnar artery is not typically chosen for CPB procedures. It is primarily involved in supplying blood to the forearm and hand, making it less suitable for the demands of cardiovascular surgery. Therefore, while the other conduits listed are established choices within surgical practice, the ulnar artery does not serve this purpose, leading