Y'know, honestly, I don't think either one really makes sense. To me, "stacking the deck" means cheating, or in other words, guaranteeing the outcome of something that otherwise would have a random possibility of occurring, through some special manipulation.
In medicine, I don't think that's possible. There's always a bell curve, or something similar, that gives a range of possible outcomes, but no way to cheat or guarantee.
That's part of what bothers me about the commercial. It implies that good luck charms or similar paranormal things are more powerful than science, and can "cheat" the odds, when the scientific odds would already in theory take into account everything that would affect the patient's chances, including the compassion of nurses, his attitude, etc.