asphyxia vs persistent vegetative state

asphyxia

noun
  • Loss of consciousness due to the interruption of breathing and consequent anoxia. 

  • Loss of consciousness due to the body's inability to deliver oxygen to its tissues, either by the breathing of air lacking oxygen or by the inability of the blood to carry oxygen. 

persistent vegetative state

noun
  • A condition of patients with severe brain damage in whom coma has progressed to a state of wakefulness without awareness. 

How often have the words asphyxia and persistent vegetative state occurred in a corpus of books? (source: Google Ngram Viewer )