Which of the following is a common complication of prolonged cardiopulmonary bypass?

Prolonged cardiopulmonary bypass (CPB) is associated with several complications due to the complex physiological changes that occur during the procedure. The correct choice highlights that all listed complications can indeed arise from extended periods of CPB.

Delayed graft patency occurs due to factors such as the inflammatory response and altered blood flow dynamics during bypass, which can affect how well grafts function postoperatively. Coagulopathy is common during and after CPB due to the consumption of clotting factors and platelets while in contact with the bypass circuit. This can lead to bleeding complications. Electrolyte imbalances often arise from hemodilution, altered kidney function, and the administration of intravenous fluids, which can disrupt the normal balance of electrolytes critical for physiological functions.

All these complications reflect the multifaceted impact of prolonged CPB on the body, thus supporting the answer that all of these components are common issues following extended periods on the bypass machine.