Acta neurochirurgica. Supplement
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The phase-contrast MRI technique permits the non-invasive assessment of CSF movements in cerebrospinal fluid cavities of the central nervous system. Of particular interest is pulsatile cerebrospinal fluid (CSF) flow through the aqueduct cerebri. It is allegedly increased in hydrocephalus, having potential diagnostic value, although not all scientific reports contain unequivocally positive conclusions. ⋯ Preliminary results indicate that the pulsations of CSF flow may carry information about both CSF-circulatory and cerebral vasogenic components. In most cases, the pulsations of CSF flow are positively related to the pulse amplitudes of both arterial pressure and ICP and to a degree of cerebrovascular dilatation.
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Acta Neurochir. Suppl. · Jan 2018
Non-invasive Intracranial Pressure Assessment in Brain Injured Patients Using Ultrasound-Based Methods.
Non-invasive measurement of intracranial pressure (ICP) can be invaluable in the management of critically ill patients. Invasive measurement of ICP remains the "gold standard" and should be performed when clinical indications are met, but it is invasive and brings some risks. In this project, we aim to validate the non-invasive ICP (nICP) assessment models based on arterious and venous transcranial Doppler ultrasonography (TCD) and optic nerve sheath diameter (ONSD). ⋯ Our results demonstrate that among the non-invasive methods studied, ONSD showed the best accuracy in the detection of ICP.
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Following brain injury, unstable cerebral hemodynamics can be characterized by abnormal rises in intracranial pressure (ICP). This behavior has been quantified by the RAP index: the correlation (R) between ICP pulse amplitude (A) and mean (P). While RAP could be a valuable indicator of autoregulatory processes, its prognostic ability is not well established and its validity has been questioned due to potential errors in measurement. Here, we test (1) whether RAP is a consistent measure of intracranial hemodynamics and (2) whether RAP has prognostic value in predicting hemodynamic instability following brain injury. ⋯ We conclude that RAP can provide a valid measure of ICP dynamics, is not affected by sensor drift, and can better distinguish periods of instability than ICP or AMP alone.
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Acta Neurochir. Suppl. · Jan 2018
Effect of Mild Hypocapnia on Critical Closing Pressure and Other Mechanoelastic Parameters of the Cerebrospinal System.
Brain arterial critical closing pressure (CrCP) has been studied in several diseases such as traumatic brain injury (TBI), subarachnoid haemorrhage, hydrocephalus, and in various physiological scenarios: intracranial hypertension, decreased cerebral perfusion pressure, hypercapnia, etc. Little or nothing so far has been demonstrated to characterise change in CrCP during mild hypocapnia. ⋯ During hypocapnia in TBI patients, ICP decreases and WT increases. CrCP increases slightly as the rise in wall tension outweighs the decrease in ICP. The closing margin remained unchanged, suggesting that the risk of hypocapnia-induced ischemia might not be increased.
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Acta Neurochir. Suppl. · Jan 2018
What Determines Outcome in Patients That Suffer Raised Intracranial Pressure After Traumatic Brain Injury?
Episodes of raised intracranial pressure (ICP) after traumatic brain injury (TBI) are responsible for the majority of secondary brain injury events and thereby strongly affect long-term outcome. However, not all patients with major episodes of raised ICP suffer a poor outcome. The aim of the current analysis was to identify variables contributing to good outcome in patients suffering episodes of high ICP. ⋯ Prolonged episodes of disturbed dynamic cerebral autoregulation contribute to detrimental outcome in patients with increased ICP. Autoregulation seems to have an important protective role in tolerating episodes of raised ICP.