My daughter in laws dad had a heart attack today.. He was rushed to hospital with no pulse, she said that they induced a coma, bc he needs bypass surgery and have to see if he is responsive, it needs 48 hrs. they wont know until monday. He is critical, tomorrow he will be 68. he is not responsive now, and was put on a respirator, now she thinks he is breathing on his own.. what does all this mean, and why do they induce a coma,