I've been thinking about stim patches and how they need to be placed on a major artery. Well, who is most likely to use one? People who fight for a living or survival. There expensive, which means only the more wealthy can afford them. Well, what else can wealthy people afford? Armor!
But when your wearing armor, you can't use a stim patch because your major viens are covered!
My idea would be for something injectable, that stops bleeding, atleast, not sure how it would work, but it would make more sense.