Neurocritical care
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To investigate the hemodynamic response of the cerebral bridging veins to increased intracranial pressure (ICP) during normo- and hyperventilation. ⋯ The cerebral bridging veins dilation and blood flow velocity decrease indicate the venous relative stasis in response to the elevated ICP. This response is proposed to be caused by an ICP-dependent increase in resistance to the outflow from the cerebral bridging veins.
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Altered brain perfusion may play an important role in the development of sepsis-associated encephalopathy. However, whether or not cerebral autoregulation (CA) is preserved in such condition has been debated. CA is dependent on cerebral vascular tone, the main determinant of which is the concentration of carbon dioxide (CO2). The purpose of this study was to evaluate the influence of PaCO2 on the cerebral autoregulatory capacity in patients with septic shock. ⋯ According to these data, CA is impaired in the majority of patients with septic shock, especially in the presence of hypercapnia.
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Comparative Study
Does stimulus rate matter when performing somatosensory evoked potentials for coma patients?
It is unclear whether the rate of stimulation for somatosensory evoked potentials (SEPs) can influence the presence or absence of cortical responses to median nerve stimulation in comatose patients. If so, this could affect how SEPs are performed and interpreted for prognostication in coma. Our objective was to determine how frequently our comatose patients had absent median nerve SEP responses at 3 Hz stimulation, but present responses at 1 Hz stimulation, and to report outcomes of these patients. ⋯ Stimulation rate is an important determinant of presence or absence of cortical responses in about 1% of comatose patients. It is unclear whether such patients have a different outcome that those with absent responses at both rates of stimulation.
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Diagnosing brain death in children is challenging. Guidelines recommend using confirmatory testing to provide ancillary information to support the diagnosis. Brain tissue oxygenation (PbtO(2)) is being increasingly used in the adult neurocritical care for continuous monitoring of the adequacy of brain oxygenation; however, data in pediatrics is limited. Evidence from adult studies suggests that persistent PbtO(2) of 0 mmHg is associated with brain death, but this relationship has not yet been demonstrated in children; therefore, we examined our experience with PbtO(2) monitoring and brain death in children with acute neurological pathology. ⋯ Preliminary data from this study suggest that PbtO(2) decreases to 0 mmHg when brain death occurs in children. Further study is needed to determine the limitations, and the sensitivity and specificity of this finding in a larger group of children.
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Although electrocardiographic (ECG) abnormalities are well known in ischemic stroke and subarachnoid hemorrhage, these changes have only rarely been investigated systematically in patients with intracerebral hemorrhage (ICH). The purpose of this study is to investigate the prevalence and type of ECG abnormalities in a consecutive series of ICH patients, and their possible association with pre-defined neurological and radiological parameters. ⋯ In ICH patients ECG abnormalities are common. QTc prolongation seems associated with insular cortex involvement, with the presence of intraventricular blood, and with hydrocephalus. A larger cohort of continuously monitored ICH patients is necessary to investigate whether these ECG abnormalities are associated with poor outcome or death.