Something that I carry on me when I'm travelling in my wallet is a piece of paper. It is written in both English and the predominant language of where I'm travelling. This paper is titled "Instructions and information for emergency personnel." It has my name, home address, blood type, allergies, short medical history, insurance numbers and international numbers to call for authorization. It also includes numbers of people who can be called for more information (like my primary care physician)
It is easy to make, write it up before the trip, run it through Google translate for the destination language, and fold it up into my wallet.
I got this idea from a friend of my father's who was a diplomat and so travelling a lot. He had stories about how it had saved his life in when he crashed his bike in the Alps. He too said that the last thing on your mind is explaining all of this stuff to people when he was injured. But once he realized that he didn't have to explain it, he only needed to let them know who to ask to get the information.