I recently ran my first code. I thought it would be horrible, but in actuality, it wasn't that bad. Of course, initially, it was miserable. I was ready to wet myself. However, after the first 5 minutes and the patient hadn't turned around, I realized something somewhat profound. This person, if I stopped right then and there, was dead. The only thing keeping the patient from being dead dead was the nurse pumping his chest and another bagging his lungs.
The thing about ICU that one of my attendings impressed on me is that you can't save everyone. Heck, you can't even save most. You do what you can with the tools given to you, and let God do the rest. The thing about the unit is that the only patients that get to the unit are ones that are dying. And if you're not dying, then you don't deserve the unit bed.
I feel better about codes now, and I've got a few under my belt. The shock of watching someone die, it goes away after a while. You do what you can with the tools you have.