ATP is Adenosine Triphosphate. ATP consists of an adenosine molecule bonded to 3 phosphate groups in a row. This occurs when a molecule of adenosine diphosphate ( ADP ) uses the energy released during cellular respiration bond with a 3rd phosphate group, becoming a molecule of ATP
I don't think doctors are supposed to do that but if they are I'm guessing it's probably to kill a infection of some kind or speed up the healing process
