Brain death confirmation
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A. Haussmann · U. Yilmaz Department of Clinical and Interventional Neuroradiology, Saarland University Medical Center, Homburg/Saar, Germany
Brain death confirmation Definition The confirmationofbraindeath is defined as clinical and instrument-based proof of the irreversible loss of the entire human brain functions, called brain death. From the medical and scientific point of view, brain death itself is the total loss of function of the cerebrum, the cerebellum and the brainstem while the cardiovascular and respiratory systems are maintained guaranteeing gas exchange in the lungs [1, 2]. These clinical and instrument-based methods are necessary for estimation of the prognosis of the disease following therapeutic approaches, independent of being a possible donor of organs or tissue. The determination of brain death is completely defined by guidelines, which are used for patients at all ages (adults and children). In cases of children under the age of 2 years specific rules have to be followed. In cases of premature babies born earlier than the 37th week of pregnancy and babies with anencephaly the whole process of brain death confirmation cannot be used.
Causes The causes of the irreversible failure of the human brain are diverse and characterized by an increase of the intracranial pressure over the mean arterial pressure causing cessation of cerebral perfusion. A distinction is made between primary and secondary causes and concerning the primary between supratentorial and infratentorial reasons. Primary cerebral causes: 4 Severe traumatic brain injury 4 Malignant stroke 4 Intracranial hemorrhage 4 Brain tumors, metastasis 4 Acute obstructive hydrocephalus
Examples for secondary reasons for brain injury: 4 Cerebral hypoxia The detailed differentiation between primary supratentorial and primary infratentorial lesions is important for the subsequent procedure of determination of brain death because in cases of infratentorial lesions an additional instrument-based diagnostic is absolutely necessary [2].
History The term coma dépassé, an irreversible coma, was first used by the French neurologists Mollaret and Goulon 1959 and 9 years later, in 1968 the ad hoc committee of Harvard Medical School defined brain death as a total loss of movement and respiration, of brainstem reflexes and unconsciousness. Mohandas and Chou [3] published that injuries of the brainstem are important aspects of severe brain damages. Because of that brain death was defined by the Conference of Medical Royal Colleges as a complete and irreversible loss of function of the brainstem 1976 [3]. This statement found its way into the guidelines and therefore the examinations of brainstem reflexes and the testing of apnea are required in the confirmation [3].
Symptoms The following symptoms should be seen in patients before starting the cascade of the brain death confirmation: 1. Unconsciousness (coma) 2. Unresponsive bilateral middle to maximum wide pupils without application of a mydriatic medication
3. Bilateral loss of oculocephalic and vestibulo-ocular refle
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