The clinical criteria of brain death throughout the world: why has it come to this?

T HE addition of neurological criteria of death – better known as brain death – to cardio-respiratory criteria of death was a paradigm shift which evolved when patients with acute brain injury could be resuscitated in emergency departments and intensive care units. Resuscitation of acute brain injury led to progression of devastating brain edema, shift, and eventually massive increase in intracranial pressure that would stop the blood flow at the entrance of the skull base. Multiple symposia were organized in Sweden, the United Kingdom, and Australia that tried to formulate brain death on the basis of neurological criteria. Brain death examination became a prerequisite to allow organ donation, and its concept has been fully accepted. Despite widespread acceptance of the criteria, there remained great variability in how brain death criteria were codified in different parts of the world. A review of the history of neurological death is presented by Baron et al. in this issue of the Journal. The gold standard A seminal paper on neurological determination of brain death was written by the Harvard ad hoc Committee. 2 There was a desire in the 1960s to produce a brief but succinct document due to a pressing need in the critical care community for guidelines. To this day, the Harvard criteria remain an example of simplicity. The criteria were as follows: 1. Unreceptivity and unresponsiveness; 2. No movement or breathing; 3. No brainstem reflexes; 4. Flat electroencephalogram; 5. All tests repeated at least 24 hr later, with no change, and exclusion of hypothermia (body temperature < 90°F or 32.2°C) or central nervous system depressants. Brain death criteria throughout the world A recent survey explored the international practices for diagnosing brain death. 3 Original brain death documents of 80 countries throughout the world were obtained. The differences in criteria were stunning. No differences appeared when the methods of examination of brainstem reflexes were compared; however, there were marked differences in how the apnea test was performed. The apnea test continued to concern physicians, although the procedure is simple and in most cases without complications. Testing the response with induced hypercarbia should remain standard if our goal is to document total brainstem destruction. Confirming apnea with a PaCO 2 target value was used in only 59% of all guidelines. In others , preoxygenation with 100% oxygen followed by a ten-minute disconnection from the ventilator was deemed sufficient (20 of 71 guidelines). There …