My father had multiple strokes during an open heart surgery...
I'm very sorry about your situation. In general, open heart surgeries come with two different types of potential neurological complications. The first is multiple small strokes. This occurs most commonly when the aorta (or the large artery coming from the heart) is unclamped near the end of the procedure. When the clamp is placed, it can crush down on cholesterol plaques that have been lying dormant for years. When the clamp is released, it can send a small shower of these cholesterol particles up to the brain, leading to multiple strokes. The other common problem occurs when the patient is placed on a cardiac bypass pump. In other words, a machine acts as a temporary "heart" to keep blood flowing throughout the body. Sometimes, this can cause a drop in the blood pressure. If a patient already has tightening in the arteries going to their brain, there can be a critical loss of oxygen and glucose from being delivered to the brain, and hence, cause some rather large strokes.
In either case, it is often very difficult for your physicians to predict recovery. Predicting recovery from a stroke is not unlike predicting the weather in a week. It is not a perfect science. Helpful clues to recovery include the total stroke burden seen on MRI scan, the amount of normal electrical activity seen on an EEG test (Electro Encephalogram), and, most importantly, the patient's rate of progress on clinical examination. In many cases where blood flow has been slowed during bypass, if the patient is not following any verbal commands even while off all sedatives by one week after the operation, the prognosis is not very promising.
Sorry that this is such an inexact science. I am sure you and your family are quite troubled by this situation. You have my sympathy
