Nature reviews. Neurology
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Nature reviews. Neurology · Mar 2013
ReviewClinical relevance of cerebral autoregulation following subarachnoid haemorrhage.
Subarachnoid haemorrhage (SAH) is a form of stroke that is associated with substantial morbidity, often as a result of cerebral ischaemia that occurs in the following days. These delayed deficits in blood flow have been traditionally attributed to cerebral vasospasm (the narrowing of large arteries), which can lead to cerebral infarction and poor neurological outcome. Data from recent studies, however, show that treatment of vasospasm in patients with SAH, using targeted medication, does not translate to better neurological outcomes, and argue against vasospasm being the sole cause of the delayed ischaemic complications. ⋯ Failure of autoregulation, therefore, has been implicated in development of delayed cerebral ischaemia. In this Review, we summarize current knowledge about the clinical effect of disturbed cerebral autoregulation following aneurysmal SAH, with emphasis on development of delayed cerebral ischaemia and clinical outcome, and provide a critical assessment of studies of cerebral autoregulation in SAH with respect to the method of blood-flow measurement. Better understanding of cerebral autoregulation following SAH could reveal mechanisms of blood-flow regulation that could be therapeutically targeted to improve patient outcome.
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Nature reviews. Neurology · Mar 2013
ReviewControversies in defining and determining death in critical care.
Circulatory-respiratory or brain tests are widely accepted for definition and determination of death, but have several controversial issues. Both determinations have been stimulated by organ donation, but must be valid independently of this process. ⋯ Controversies about the circulatory determination of death include the minimum duration of asystole that is sufficient for death to be declared, and whether the distinction between permanent and irreversible cessation of circulatory functioning is important. In addition, the goal of organ donation raises issues such as the optimal way to time and conduct the request conversation with family members of the patient, and whether the Dead Donor Rule should be abandoned.