In fact, only one intervention has been conclusively shown to improve neurological outcome and survival after cardiac arrest, and you probably already know what it is: hypothermia.

Took us long enough: therapeutic hypothermia was first used in the 19^th century. And it was first employed for neuroprotection in the 1940s. Unfortunately, at that time, target temps were considerably lower than todays, and there were big problems with arrhythmias, coagulopathy, shivering and sepsis, along with technical problems with instituting the therapy. Eventually, people got tired of that crap, and hypothermia was abandoned.  

Today is a different story. Hypothermia with target temperatures of 32-34 deg C has been demonstrated in clinical trials to improve neurological outcome and mortality, and to be relatively free of side effects. It's not perfect, but at long last, we have something that works.

Figure. Gonna be cool like Fonzie. A patient being fitted with the Arctic Sun hypothermia apparatus.