Source : WordNet®

life support
     n 1: equipment that makes life possible in otherwise deadly
          environmental conditions; "the astronauts relied on
          their life-support systems" [syn: {life-support system}]
     2: medical equipment that assists or replaces important bodily
        functions and so enables a patient to live who otherwise
        might not survive; "the patient is on life support" [syn:
        {life-support system}]