This speedy little droid was designed to locate wounded soldiers during combat and either see to their wounds in the field, or drag the soldier back to a mobile medical facility. The droid was not a dedicated medical droid and was only able to make a diagnostic of the soldier's wounds and apply the most basic of first aid.
Another downside to the GHT line was that the location of each wounded soldier had to be uploaded directly into the droid's brain before it could locate the individual. Later modifications would add auto-map software to the droids, in a effort to speed up the retrieval process.
During the Galactic Civil War, Rebel forces used the GHT almost exclusively. Soldiers were given medical transponders which, when activated, would "call" a GHT to his location for aid. In an effort to hamper the droids, the Empire would flood areas with false transponder signals. When the droids arrived at the scene, Imperial sharpshooters would pick them off one by one.