Design Origin and Meaning
The blue “Star of Life” symbol was designed for NHTSA in response to the need for a uniform symbol representing the emergency medical services system. The six barred cross was adapted from the personal Medical Identification Symbol of the American Medical Association. For EMS the six bars represent the six systems functions:  Detection,  Reporting,  Response,  On Scene Care,  Care in Transit and  Transfer to Definitive Care.
Staff of Asclepius (Greek)
Asclepius was the Greek god of medicine. In Greek mythology he was the son of Apollo (god of light, truth, and prophecy) and the nymph Coronis. The centaur Chiron taught him the art of healing, but Zeus (the king of gods), afraid that he might render all men immortal, slew him with a thunderbolt. Homer, in the iliad, mentions him only as the skilled or “peerless physician” and further identifies him as the father of Podaleirus and Machaeon, physicians to the Greeks in the Trojan War. In later times, however, he was honored as a hero and eventually worshipped as a god. The cult of Asclepius began in Thessaly, but spread to many parts of Greece. Since it was supposed that he effected cures or prescribed remedies to the sick in dreams, the practice of sleeping in his temples became common.
Asclepius was frequently represented standing, dressed in a long cloak, with bare breast; his usual attribute was the staff with a serpent coiled around it. The staff is the only true symbol of medicine. The Caduceus with its winged staff and intertwined serpents, used as a medical emblem by the Military Medical Corps and some physicians, is without medical relevance in its origin since it represents the magic wand of Hermes (in Greek mythology a diety; herald and messenger of the gods; gods of roads, commerce, invention, cunning, and theft; patron of traders and rogues; and conductor of the dead to Hades) and Mercury of Roman mythology, often identified with Hermes, who served also as messenger to the other gods and was god of commerce, travel and thievery.
In 293 B.C. because of the plague, the Romans adopted the cult of Aclepius who became known in Roman mythology as Aesculapius.
It is considered most appropriate to call attention to the other significant reference to the serpent on a staff associated with healing as follows:
“Moses accordingly made a bronze serpent and mounted it on a pole and whenever anyone who had been bitten by a serpent looked at the bronze serpent, he recovered.” – Numbers 21:9
Originally, many ambulances used an Omaha orange cross on a square background of reflectorized white to designate them as emergency units. This logo was used before national standards for Emergency Medical Personnel or ambulances were established. Designed by Leo R. Schwartz, Chief of the EMS Branch, National Highway Traffic Safety Administration (NHTSA), the Star of Life was created after the American National Red Cross complained in 1973 that the orange cross too closely resembled their logo, the red cross on a white background. The newly designed cross was adapted from the Medical Identification Symbol of the American Medical Association, which was patented by the American Medical Association (AMA) in 1967. The newly designed logo was trademarked on February 1, 1977 with the Commissioner of Patents and Trade-marks in the name of the National Highway Traffic Safety and Administration (registration number 1058022). The logo was ‘given’ to the National Registry of Emergency Medical Technicians (NREMT) for use as the emergency medical technicians (EMT) logo after the trademark expired in 1997.