The bar code I am assuming is either 2D or 3 of 9, the only reason for 3 of 9 is it seems to be the most utilized. The only downfall I see is you have to hope your card stays attached during the forces of the collision, and for argument, let's say it did. Now we have to hope ths EMS and ER Staff, one of them is technical enough to know how to download and install an app, and my guess is, due to HIPAA (Healthcare Information Portability and Privacy Act) they won't have access to install an app, so you have to rely on them to use their personal cel phone to scan the bar code with. I have worked on some systems in Hospitals where personal cell phones are prohibited while working, and 1 that goes so far as to only allow their cell phones to be used on the premises if you are an employee or contractor, unless you have a phone without a camera, and it must be approved. This is all due to Privacy Laws, and Health Care Providers trying to keep their data secure. I doubt anyone is looking at reading information from something inbound, they think of how to prevent it from going outbound.