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Applications , Diagnosis of brain death

المؤلف:  Sue Jickells , Adam Negrusz (Editors)

المصدر:  Clarkes Analytical Forensic Toxicology

الجزء والصفحة:  222

2026-10-15

302

Applications

Diagnosis of brain death

A patient with brain death may be a potential donor of organs. In such cases, the patient should have a deep coma of known origin with no indication of a central infection, and have normal metabolic parameters. When the primary cause of coma is drug overdose, it is important to ensure that the drug has been eliminated prior to confirming the diagnosis of brain death. This also applies to drugs that may have been given in therapy. For example, thiopental is often given in the treatment of brain oedema and during neurosurgery. The half-lives of thiopental and its metabolite, pentobarbital, increase if cardiac function is diminished or the patient is hypothermic, and therefore plasma concentrations of both compounds must always be measured. Midazolam and diazepam are also administered frequently in treating cases of brain damage, and the continued presence of active concentrations of these drugs and their metabolites should also be excluded using specific and sensitive procedures, such as high-performance liquid chromatography (HPLC). Even if benzodiazepines or their metabolites cannot be detected, there remains the possibility that some may still be present, for instance hydroxy midazolam glucuronide in active concentrations. This may suggest a provocation test with the specific benzodiazepine antagonist, flumazenil. In all other cases flumazenil is contraindicated in cases of poisoning, as many drugs may induce seizures, which just require a benzodiazepine as antidote. Similarly, the presence of active levels of anticonvulsants (phenobarbital, carbamazepine, phenytoin and valproate), which are also given in the treatment of brain damage, must be excluded. Again, the use of sensitive and specific chromatographic methods is essential.