Oh boy oh boy oh boy oh boy.....
Lots of sarcasm there.
This is one of the things I've gotten to deal with my entire life, it's a happy little thing....
More sarcasm.
The difficulty with open heart surgery (one of them anyways) is that it's rather difficult to cut and sew a moving target so they generally like to stop the heart from beating before working on it. There are some instances, usually during "minor repairs" where they've tried working on it in motion. Back in the day (when I had my first surgery, in the 70's) the best way they had to stop the heart was by packing you in ice, lots of it, head and torso usually, to bring down your core body temperature inducing hypothermia which stopped the heart. It works ok and all, but the problem is the brain isn't getting the oxygen it needs (the the amount needed is reduced) so you have to move quickly. The big downside to this is it causes brain damage (more or less) and most kids that survive the surgery end up with something like a mild learning disability or whatever. I can't do rote memorization (suck at math and art history) and I can be easily distracted at times. I work around it easily enough most times, I'm not a mathematician....
Along comes the heart/lung by-pass. Operations can last longer and more can be done, however when you run blood through plastic tubing and such, you damage the blood cells and that can decrease how much oxygen is getting to the brain over a period of time after surgery (generally the oxygen depletion during surgery isn't as bad as the ice method, as is my understanding)
So there may be some temporary memory loss or decreased mental function. You might wander around feeling a little "dumber" than you used to be for a while, but generally it gets better.
I still have some "dull moments" but they aren't as bad as when I first got home.
There's also a memory loss associated with the medications they have you on in hospital. I can't remember about five weeks or so worth of my stay in Cleveland. Part of that is because I was essentially in a coma and there just wasn't anything to remember and part of that was medication induced.
I have a few vague impressions, like dreams, of an altered reality. I remember someone who was my girlfriend/fiance, but she wasn't Erica. I remember a different room that I was in, odd drapes and an elderly couple in the next bed, but I KNOW that never happened because I spent all of my time in children's wards. I remember my extended family taking me on a special trip after surgery, with medical care on hand and a train ride....
I even had some kind of a dream about being on a space ship....
I was on some REALLY good drugs man.
I think most impaired brain function from the heart/lung machine comes back after a while. It's different for different people and it's probably related to how well your body can replace those damaged red blood cells with new ones.
It's temporary.