pump head
n.— «Clinton stands a good chance of fully rebounding from the bypass surgery, in which doctors replace clogged arteries to the heart with veins and arteries taken from elsewhere in the body. But many people who undergo the procedure…find that their brains don’t function as well as they did before.…In the medical world, this effect is commonly referred to as “pump head,” reflecting the widespread, though unproven, belief that the condition is caused by the heart-lung machine.» —“Heal the heart, hurt the mind?” Los Angeles Times Oct. 4, 2004. (source: Double-Tongued Dictionary)