Wiktionary
vital sign
n. (context medicine English) A particular component of a patient's vital signs
WordNet
vital sign
n. sign of life; usually an indicator of a person's general physical condition; "he was still alive but his vital signs were weak"
Usage examples of "vital sign".
As soon as Miles arrived in sick bay, an anxious tech administered a brain scan, drew blood, took samples of every fluid his body could be made to exude, and rechecked every vital sign he possessed.
He took one look over my shoulder at Marjorie's body and immediately checked for pulse-rate, for respiration, for any vital sign that she could still be saved.
Sometimes a tracked vital sign disappears completely, without explanation, without trace.