Acta neurochirurgica. Supplement
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Acta Neurochir. Suppl. · Jan 2020
Spreading Depolarization during the Acute Stage of Experimental Subarachnoid Hemorrhage in Mice.
Spreading depolarization (SD) has been suggested as a pathomechanism for delayed cerebral ischemia after subarachnoid hemorrhage (SAH). However, the role of SD during the acute phase of SAH is still unclear. The objective of this study was to investigate (a) the occurrence of SD with intrinsic optical signal (IOS) imaging, (b) the effect of ketamine on SD, and (c) the resulting brain edema (brain water content (BWC)) during the acute stage of experimental SAH in mice. ⋯ These results demonstrate that SD occurs with a high incidence during the acute stage of SAH. SDs are heterogeneous in incidence, origination, and propagation. It remains unclear whether ketamine effects on SD may be viewed as therapeutically beneficial after SAH.
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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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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.
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Acta Neurochir. Suppl. · Jan 2018
Occurrence of CPPopt Values in Uncorrelated ICP and ABP Time Series.
Optimal cerebral perfusion pressure (CPPopt) is a concept that uses the pressure reactivity (PRx)-CPP relationship over a given period to find a value of CPP at which PRx shows best autoregulation. It has been proposed that this relationship be modelled by a U-shaped curve, where the minimum is interpreted as being the CPP value that corresponds to the strongest autoregulation. Owing to the nature of the calculation and the signals involved in it, the occurrence of CPPopt curves generated by non-physiological variations of intracranial pressure (ICP) and arterial blood pressure (ABP), termed here "false positives", is possible. Such random occurrences would artificially increase the yield of CPPopt values and decrease the reliability of the methodology.In this work, we studied the probability of the random occurrence of false-positives and we compared the effect of the parameters used for CPPopt calculation on this probability. ⋯ This value can be minimised by tuning some of the calculation parameters, such as increasing the calculation window and increasing the minimum PRx span accepted on the curve.