Hi, I understand your concern and prolonged cardiac arrest (greater than 10 minutes) can cause severe brain damage and this is likely to be the cause of the delay in your father s recovery awareness. Usually, after a coronary artery bypass graft surgery, patients agree so ends the effect of the anesthesia medications, which can take a few minutes to a few hours (usually less than 6 hours). As I understand taht your father woke well after surgery and after about 6 to 7 hours suffered two cardiacs arrest and only regained heartbeat after 40 minutes. Any cardiac arrest is a very serious problem and it is necessary to follow a series of steps for cardiopulmonary resuscitation be effective. In the case of a cardiac arrest in the immediate postoperative period of cardiac surgery is an extreme risk of death problem. During cardiac arrest blood flow to the brain is reduced very significantly, resulting in a low supply of oxygen and nutrients to the brain. This low cerebral perfusion can cause severe damage. The longer the heart attack, the greater the chance of severe brain injury. Commonly, when the brain damage is mild, the patient wakes up a few minutes after the recovery of heart rate. However, after a very prolonged resuscitation cardioplumonar as to what happened to his father, it is common that doctors need to use sedatives to keep the patient under mechanical ventilation with endotracheal tube. If your father is using these sedatives, it may take several days to wake up, to the extent that the effects of sedatives end up. On the other hand, if your father has not used any sedative that period, it is likely that his brain damage is severe. Thus, it is possible that it takes weeks to wake up or not even wake up. I m sorry to have to tell it to you. I hope your father gets better soon and that this whole situation was just a scare.