Interest of Real Time Measurement of Autonomous Nervous System for the Detection of Brain Death: the MEANS Study

Context: A major lack of organ donors is a serious public health problem. It determines a prolonged delay before a transplant can be performed and thus a significant number of deaths of patients waiting for transplantation. The aim of this project is to reduce the delay of the diagnosis of brain death, and also to improve its diagnosis in the Intensive Care Unit.

The diagnosis of brain death is strictly defined by the law and relies either on two consecutive flat electroencephalograms recorded at an interval of four hours, or on the lack of cerebral circulation during a brain angiography performed after suspecting brain death on the clinical exam. However, in usual practice, it is difficult to have all the needed clinical arguments, and their interpretation can be difficult in the pathological context. This may participate in the delay and the lack of patients potentially donors.

Pre-study: In a pilot study, fifty subjects with severe cerebral lesions, had a continuous ECG recording. The investigators could find that a decrease in autonomic nervous system activity, as measured through the ECG, was correlated to the transition to brain death assessed by cerebral angiography. The loss of cardiac variability was always observed between two cerebral angiographies, one before and the second after brain death. This study allowed the investigators to calculate the threshold values of sympathetic and parasympathetic activities to confirm brain death.