The news reports about the Pope’s recent cautionary remarks on the determination of death include quotes from a Vatican newspaper describing false assumptions about the use of brain death as the definition of death.
The whole brain criteria for brain death is not based on the cessation of function of the brain. Instead, it is based on our knowledge that when the upper and lower brain have died, degeneration of the body will always follow, at least with current medical technology. The cascade of lower brain death always leads to failure of cardiac and respiratory function without medical intervention. We are able to maintain the heart beat and artificially inflate the lungs for longer and longer periods each year, thanks in part to better and better medications to support blood pressure and kidney function. However, with the serial verification of lower brain death, there has never been renewed function of the brain stem. Brain cells die in 6-7 minutes after being denied blood flow. The rest of the body’s cells will die when the brain does not drive the respiratory reflex or send the nerve signal to the heart to beat.
(In the case that we do hear of a man who came back to life after being declared brain dead, it does not appear that the first test was repeated.)
The Pope’s remarks were given at a conference on organ donation, held at the Vatican by the Pontifical Academy for Life, the International Federation of Catholic Medical Associations, and the Italian National Transplant Center.