Neurocritical care
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Noninvasive ventilation (NIV) is being increasingly used in patients with chronic neuromuscular disorders, but the optimal ventilation mode remains unknown. We compared physiological short-term effects of assist/controlled ventilation (ACV) and two pressure-limited modes (pressure-support ventilation [PSV] and assist pressure-controlled ventilation [ACPV]) in patients with neuromuscular disease who needed NIV. ⋯ In chronic, stable patients with neuromuscular disease, both noninvasive ACV, ACPV, and PSV had similar effects on alveolar ventilation and respiratory muscle unloading, despite some differences in the pattern of breathing and percentage of triggered cycles.
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Case Reports
Continuous bleeding from a basilar terminus aneurysm imaged with CT angiography and conventional angiography.
We report a case of fatal subarachnoid hemorrhage from nontraumatic rupture of an aneurysm at the basilar terminus in which both computed tomography angiography and conventional angiography showed evidence of active bleeding. The time period from initial ictus to CT angiography was 30-50 minutes and to conventional angiography was 120-140 minutes. This case illustrates that aneurysmal bleeding is not necessarily as brief as a few seconds and can last up to 30 to 50 minutes and perhaps longer. Continued bleeding from an intracranial aneurysm is a rare event that can be recognized using computed tomography angiography and likely indicates a poor prognosis.
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The acceptance of brain death by society has allowed for the discontinuation of "life support" and the transplantation of organs. The standard clinical criteria for brain death, when rigorously applied, ensure that the brainstem is destroyed. Because more rostral structures are more vulnerable than the brainstem, these are almost invariably devastated when brainstem function is irreversibly lost as a result of whole brain insults. ⋯ Ancillary tests are also required in very young children. In addition, some societies require their use as a matter of principle. Only tests of whole-brain perfusion adequately serve these purposes.
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This review examines the available data on the use of osmotic agents in patients with head injury and ischemic stroke, summarizes the physiological effects of osmotic agents, and presents the leading hypotheses regarding the mechanism by which they reduce ICP. Finally, it addresses the validity of the following commonly held beliefs: mannitol accumulates in injured brain; mannitol shrinks only normal brain and can increase midline shift; osmolality can be used to monitor mannitol administration; mannitol should be not be administered if osmolality is >320 mOsm; and hypertonic saline is equally effective as mannitol.