My husband went into cardiac arrest when he was 21 (yeah, super young, I know) and he was sedated and intubated for at least 24 hours. They tried weaning him off the sedation the day after but he kept fighting the breathing tube, so they kept him on it until he came out of the sedation on his own and then they extubated him.

He turned out perfectly fine, no lasting effects except now he has an implanted defibrillator in his chest in case it ever happens again.