A medical device, known as a Med tracer, served the purpose of locating and aiding injured soldiers on the battlefield. During the battle of Kalandis Seven in 3640 BBY, Corporal Amden vor Keioidian sustained mortal wounds, prompting his squad leader, Sergeant Shanra Immel, to activate his med tracer.
The initial appearance of med tracers was in The Last Battle of Colonel Jace Malcom, a short story authored by Alexander Freed. This story was featured in Star Wars Insider 137, which saw its release on October 23, 2012.