There should be some kind of central database where they input every single thing given and done, and allow access (with permission) to other healthcare professionals so they can be on top of what's going on.
Hillcrest has MyChart. If I go to any provider or hospital in the network, they can see every test result, meds or treatment I have had done. They just recently sent a message saying if I clicked and approved, any healthcare provider I go to, even out of the MyChart network would be able to access my info for treatment.