Results of four technical investigations in fifty clinically brain dead patients

Abstract

Fifty consecutive patients (aged 19-77 years, median 56 years) with primary cerebral diseases and the clinical signs of absent cortical and brainstem function were subjected to electroencephalography (EEG), brainstem acoustic evoked potentials (BAEP), extracranial Doppler ultrasonography (ECD) and arterial digital subtraction angiography (DSA). In the majority of cases the results of the technical tests agreed with the clinical signs and were suggestive of brain death. However, in one patient EEG revealed clear bioelectrical activity. In 6 cases, doubts existed about whether the EEG was isoelectric; in 3 of the 6 cases biological activity might have been present. In 31 of 42 patients ECD showed a typical pattern of intracranial circulatory arrest, in 9 of 42 ECD revealed a pattern suggestive of the cessation of cerebral blood flow. In four patients BAEP recordings compatible with brain death were recorded 2-3 days before intracranial circulatory arrest. In 2 patients with isoelectric EEG and absent BAEP arterial DSA demonstrated residual perfusion. The findings are discussed in view of the conceptional differences concerning brain death. It is concluded that the strict application of the concept of death of the whole brain requires angiographic demonstration of absent intracerebral blood flow.

Brain death: resolving inconsistencies in the ethical declaration of death

“…In the setting of normal arterial pressures, technetium 99 hexamethylpropyleneamineoxime (Tc99-HMPAO) perfusion scanning, or four-vessel selective cerebral contrast dye angiography can accurately assess anterior and posterior cerebral circulation (that is 'whole brain' blood flow). 44,45 Tc99-HMPAO scanning is usually performed with dynamic and static imaging. The dynamic imaging can quickly assess the presence or absence of intracranial perfusion, whereas static imaging detects any uptake of the tracer by functioning neurons.…”

Usefulness of venous oxygen saturation in the jugular bulb for the diagnosis of brain death: report of 118 patients

“…Although an iso-electric EEG is accepted as a parameter of absent cortical function and in many countries EEG silence may replace the observation period, it has been shown that bio-electrical activity may be present in patients meeting the criteria of brain death even showing circulatory arrest [24]. Moreover, EEG is susceptible to technical inadequacies and observer errors [25,26,27,28].…”

“…Moreover, EEG is susceptible to technical inadequacies and observer errors [25,26,27,28]. The strict application of the concept of death of the whole brain requires angiographic demonstration of absent intracerebral blood flow [24]. Evoked cerebral potentials can demonstrate the successive loss of activity of the various afferent pathways and are accepted in some countries as a confirmatory test, but in primary infratentorial lesions the activity of the cerebral cortex can survive the loss of brainstem function by a number of hours or days.…”

Brief review: The role of ancillary tests in the neurological determination of death

“…13 In another series one of 50 adult patients had residual EEG activity. 14 Alvarez et al found no false negatives for EEG in 28 children who met clinical criteria for brain death. 15 Studies to determine the false positive rate (in which the EEG is flat in patients who are not brain dead) are lacking, except for isolated case reports.…”