Inducing hypothermia is pretty commonly accepted practice in this situation, though after reading the recent data, doesn’t seem to make a big difference (I was surprised to find this article from NEJM below). Data in support is pretty mixed.
Survival is basically a coin flip either way, though hopefully Hamlin’s otherwise healthy status will shift those odds in his favor a bit. And of course some that survive will have long term deficits.
I think part of the problem for these out of hospital arrests is that even with perfect care, there is almost no logistical way to start the process during the truly vulnerable window when there is no blood flow to the brain.
You can try to play catch up at the hospital and decrease the neuron demand for oxygen during the recovery phase, but often it’s simply too late.
Restoring and maintaining a normal electrical rhythm with a pulse ASAP is the critical factor here more than anything else.