Acta neurochirurgica. Supplement
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Acta Neurochir. Suppl. · Jan 2018
Computed Tomography Indicators of Deranged Intracranial Physiology in Paediatric Traumatic Brain Injury.
Computed tomography (CT) of the brain can allow rapid assessment of intracranial pathology after traumatic brain injury (TBI). Frequently in paediatric TBI, CT imaging can fail to display the classical features of severe brain injury with raised intracranial pressure. The objective of this study was to determine early CT brain features that influence intracranial or systemic physiological trends following paediatric TBI. ⋯ The size of the basal cisterns, the presence of subarachnoid blood or an extra-axial mass are all related to disturbed ICP and pressure reactivity in this paediatric TBI cohort. Patients with these features are ideal candidates for invasive multimodal monitoring.
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Acta Neurochir. Suppl. · Jan 2018
Induced Dynamic Intracranial Pressure and Cerebrovascular Reactivity Assessment of Cerebrovascular Autoregulation After Traumatic Brain Injury with High Intracranial Pressure in Rats.
In previous work we showed that high intracranial pressure (ICP) in the rat brain induces a transition from capillary (CAP) to pathological microvascular shunt (MVS) flow, resulting in brain hypoxia, edema, and blood-brain barrier (BBB) damage. This transition was correlated with a loss of cerebral blood flow (CBF) autoregulation undetected by static autoregulatory curves but identified by induced dynamic ICP (iPRx) and cerebrovascular (iCVRx) reactivity. We hypothesized that loss of CBF autoregulation as correlated with MVS flow would be identified by iPRx and iCVRx in traumatic brain injury (TBI) with elevated ICP. ⋯ In TBI with high ICP, high-velocity MVS flow is responsible for the loss of CBF autoregulation identified by iPRx and iCVRx.
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Acta Neurochir. Suppl. · Jan 2018
Visualisation of the 'Optimal Cerebral Perfusion' Landscape in Severe Traumatic Brain Injury Patients.
An 'optimal' cerebral perfusion pressure (CPPopt) can be defined as the point on the CPP scale corresponding to the greatest autoregulatory capacity. This can be established by examining the pressure reactivity index PRx-CPP relationship, which is approximately U-shaped but suffers from noise and missing data. In this paper, we present a method for plotting the whole PRx-CPP relationship curve against time in the form of a colour-coded map depicting the 'landscape' of that relationship extending back for several hours and to display this robustly at the bedside.This is a short version of a full paper recently published in Critical Care Medicine (2016) containing some new insights and details of a novel bedside implementation based on a presentation during Intracranial Pressure 2016 Symposium in Boston. ⋯ We describe here a natural extension to the concept of autoregulatory assessment, providing the retrospective 'landscape' of the PRx-CPP relationship extending over the past several hours. We have incorporated such visualisation techniques online in ICM+. The proposed visualisation may facilitate clinical evaluation and use of autoregulation-guided therapy.
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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
ICP Monitoring by Open Extraventricular Drainage: Common Practice but Not Suitable for Advanced Neuromonitoring and Prone to False Negativity.
A drawback in the use of an external ventricular drain (EVD) originates in the fact that draining cerebrospinal fluid (CSF) (open system) and intracranial pressure (ICP) monitoring can be done at the same time but is considered to be unreliable regarding the ICP trace. Furthermore, with the more widespread use of autoregulation monitoring using blood pressure and ICP signals, the question arises of whether an ICP signal from an open EVD can be used for this purpose. Using an EVD system with an integrated parenchymal ICP probe we compared the different traces of an ICP signal and their derived parameters under opened and closed CSF drainage. ⋯ The general practice of draining CSF and monitoring ICP via a (usually open) EVD plus frequently performed catheter closure for ICP reading is feasible for assessment of overall ICP trends. However, it does have clinically relevant drawbacks, namely, a significant amount of undetected increases in ICP above thresholds, and continuous assessment of cerebrovascular autoregulation is less reliable. In conclusion, all patients who need CSF drainage plus ICP monitoring due to the severity of their brain insult need either an EVD with integrated ICP probe or an EVD line plus a separate ICP probe.