Vital signs are signs of life. The clinical vital signs usually refer to temperature, pulse and respiration. The term "vital signs absent (VSA)" simply means that after gross inspection the patient does not seem to have signs of life. However it should be stressed that an individual with VSA is not necessarily dead as some drown victims who were initially VSA but later resuscitated without much lasting neurological damage. A review of the criteria for brain death is helpful.
Selected vital signs links: