"Deep coma" refers to a very long and profound state of unconsciousness where a person is unresponsive to their surroundings and unable to wake up. Full definition
It was hard not to think of him suddenly waking against the soft, invisible satin like the hundreds of people who had been buried in deep comas only to wake beneath the earth in terror. (bookbrowse.com)
Veatch would declare dead anyone who is persistently «vegetative,» who, despite being in a deep coma, continues to breathe and have sleep - wake cycles, and who actually may be aware of external stimuli, though it may be difficult to detect their awareness except by complex neurophysiologic imaging. (firstthings.com)
It tackles the important question of how we should care for people who are gravely handicapped or ill, including those who are in a deep coma and apparently unresponsive to any ordinary form of stimulus. (faith.org.uk)