Concepts and diagnosis of brain death.

The different concepts of brain death are subject to controversial debate. It is outlined that only the whole-brain concept, that is the irreversible loss of all functions of the entire brain, is consistent with the death of man. Cortical death or brain-stem death should not be considered in this respect. The operational procedure for determining brain death is outlined with special regard to those cases in which a definite diagnosis cannot be made clinically. It is shown that apnea testing must be accompanied by blood-gas analysis, as it may take 15 min for the PaCO2 to achieve the desired level of 8 kPa. The problem with CNS-depressing drugs and their metabolites interfering with the clinical diagnosis--e.g. sedatives, barbiturates, opioids--is described, and it is stressed that, in these cases, the cerebral panangiography (digital subtraction angiography with catheter tip in the aortic arch) is the gold standard for the final and definite proof of brain death.