Neurocritical care
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Comparative Study
Non-invasive methods of estimating intracranial pressure.
Non-invasive measurement of intracranial pressure can be invaluable in the management of critically ill patients. We performed a comprehensive review of the literature to evaluate the different methods of measuring intracranial pressure. ⋯ In addition, multiple techniques of measuring the optic nerve and the optic nerve sheath diameter have been studied. Ultrasound measurements of the optic nerve sheath diameter and Doppler flow are especially promising and may be useful in selected settings.
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Craniotomy is potentially life-saving in selected patients with intracerebral hemorrhage (ICH). Aside from specific scenarios (cerebellar hemorrhage with hydrocephalus, midline shift from an accessible lesion, etc.) the indications for surgical decompression are controversial. Based on the earlier work that aspirin and reduced platelet activity are associated with larger hemorrhage size and hemorrhage growth, we tested the hypothesis that aspirin or reduced platelet activity would be associated with increased odds of craniotomy, likely through hemorrhage growth. ⋯ After correction for ICH volume and location, aspirin use or reduced platelet activity was associated with similar increased odds for craniotomy.
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Although the new Practice Parameters for brain death support a single examination, there is paucity of data comparing its impact to dual brain death (DBD) examinations. ⋯ SBD exam is easier, faster to perform, with no brain function recovery and leads to similar donation rates, equivalent or better organ function status at the time of BD and lower cost than conventional DBD exams.
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Comparative Study
Dose-dependent influence of sevoflurane anesthesia on neuronal survival and cognitive outcome after transient forebrain ischemia in Sprague-Dawley rats.
Volatile anesthetics reduce postischemic neurohistopathological injury and improve neurological outcome in various animal models. However, the isoflurane concentrations above 1 minimum alveolar concentration (MAC) have been associated with reduced neuronal survival and impaired functional outcome. The aim of this study was to evaluate if 1.8 MAC sevoflurane alters postischemic neuronal survival and neurologic outcome compared with 0.45 MAC sevoflurane. ⋯ Postischemic neuronal survival was increased with 1.8 MAC compared with 0.45 MAC sevoflurane. Therefore, experimental models of cerebral ischemia should account for neuroprotective effects of sevoflurane with increasing concentrations. To ensure minimal interference of sevoflurane on neuronal survival, a low inspired concentration should be used and fluctuations in the depth of anesthesia should be limited.
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Comparative Study
Comparison between cerebral tissue oxygen tension and energy metabolism in experimental subdural hematoma.
An experimental swine model (n = 7) simulating an acute subdural hematoma (ASDH) was employed (1) to explore the relation between the brain tissue oxygenation (PbtO(2)) and the regional cerebral energy metabolism as obtained by microdialysis, and (2) to define the lowest level of PbtO(2) compatible with intact energy metabolism. ⋯ PbtO(2) monitoring accurately describes tissue oxygenation but does not disclose whether the oxygen delivery is sufficient for maintaining cerebral energy metabolism. Accordingly, it may not be possible to define a threshold level for PbtO(2) below which energy failure and permanent tissue damage occurs.