Dr. Yonatan Halevy
Coma is a prerequisite for brain death, but it is not enough. I mean, patients in coma wake up all the time. I mean, coma is a wider, where there are various degrees of damage to the brain, many of them reversible. I mean, if we take what we call persistent vegetative state today (PVS), this is very far from brain death. These are the stories that you read in the papers, that after 9 years, the patient woke up.
Most of these patients are not even on a respirator. In order to even consider brain death, you have to have a deep coma; the most basic reflexes are absent, like the corneal reflex, the reaction of the pupils to life which are very basic; you need the patients to be in extremely deep coma in order to have this; you have to have no spontaneous respiration; as I said, you disconnect the patient from the respirator, and for 5 minutes, you don’t see any spontaneous respiration; of course, a flat curve of the electrical activity of the brain (the electrocephologram); no response to any external stimuli – – to the IO region and the E region represented in the brain; and no blood supply to the brain.
So, coma is only one prerequisite. And most patients in coma are not brain dead. But all brain dead patients definitely have to be in deep coma.