Acta neurochirurgica. Supplement
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Acta Neurochir. Suppl. · Jan 2012
Monitoring of the association between cerebral blood flow velocity and intracranial pressure.
Slow waves in intracranial pressure (ICP) are believed to originate from changes in cerebral blood volume secondary to adjustments in arteriolar diameter. Blood flow velocity (FV) signals recorded with transcranial Doppler ultrasound show similar oscillations. We investigated a continuous measure of FV/ICP association and its relationship to cerebral perfusion pressure (CPP), ICP, cerebral autoregulation (CA) and outcome after severe traumatic brain injury (TBI). ⋯ FIx correlated with ICP (Spearman's R = -0.40, p < 0.01), Mx (R = -0.54, p < 0.00005) and CPP (R = 0.34, p < 0.01), but not with PRx (p = 0.84). FIx was significantly associated with outcome after grouping into Glasgow Outcome Score (GOS) 1-3 or GOS 4-5 (Mann-Whitney p = 0.009). FIx may provide unique insights into the behaviour of the cerebral circulation during intracranial hypertension.
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Acta Neurochir. Suppl. · Jan 2012
Correlation of clinical outcome and angiographic vasospasm with the dynamic autoregulatory response after aneurysmal subarachnoid hemorrhage.
A certain correlation between unfavorable clinical outcome, incidence of vasospasm, and impaired pressure autoregulation in patients following aneurysmal subarachnoid hemorrhage (aSAH) has been suggested. However, determination of vasospasm is inaccurate and the measurement technique of cerebral vasoreactivity seems not to have been sufficiently validated. Therefore, a correlation of clinical outcome and the extent of angiographic VS was performed using an established autoregulation test. ⋯ Incidence of angiographic vasospasm and impaired clinical outcome seems to be related to impaired pressure autoregulation following aSAH.
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Acta Neurochir. Suppl. · Jan 2012
Comparing brain tissue oxygen measurements and derived autoregulation parameters from different probes (Licox vs. Raumedic).
We investigated two commercially available probes for measurement of the partial pressure of brain tissue oxygen (PbrO2) and calculation of the index of brain tissue oxygen pressure reactivity (ORx) in 7 patients after aneurysmal subarachnoid hemorrhage (SAH). Simultaneous monitoring of PbrO2 using the Licox(®) probe and the multiparameter Raumedic probe (Neurovent PTO(®)), measuring PbrO2, intracranial pressure (ICP) and brain temperature (Neurovent PTO) was performed for a median of 9 days (range 7-17 days). Both probes provided stable monitoring throughout the desired period. ⋯ There was a difference in the measurement of PbrO2 of -2.73 ± 10.1 mmHg (Licox - Raumedic). The difference in the two values for the calculated ORx was far smaller (0.03 ± 0.31; Licox - Raumedic) and the correlation coefficient higher than for both values of PbrO2 (0.76 for ORx vs. 0.56 for PbrO2). The calculation of the autoregulation parameter ORx seemed more independent of the measurement process than the measurement of PbrO2 itself and signifies the potential clinical importance of this parameter.
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Acta Neurochir. Suppl. · Jan 2012
Pulse amplitude and Lempel-Ziv complexity of the cerebrospinal fluid pressure signal.
The complexity of the intracranial pressure (ICP) signal decreases with intracranial hypertension in children with acute brain injury as well as during infusion studies in adults with hydrocephalus. In this study we have analysed the pressure signal obtained in the lumbar subarachnoid space during infusion testing. The pulse amplitude rises when the ICP is increased by additional external volume. Our objective was to determine the relative influence of the pressure range and pulse amplitude on the loss of complexity observed during infusion-related intracranial hypertension. ⋯ The pulse amplitude of the CSFP signal seems to be a major determinant of the waveform complexity.
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Acta Neurochir. Suppl. · Jan 2012
Bioinformatics analysis of mortality associated with elevated intracranial pressure in children.
Multivariate data analyses have the potential to enrich the use of the complex plethora of data gathered in the care of critically ill patients. We sought to apply hierarchical cluster analysis to investigate factors affecting outcome in children with acute brain injury requiring ICP monitoring. ⋯ The dose of abnormal ICP may contribute to outcome in insults that involve increased ICP. These results are proof of principle of the potential application of hierarchical clustering to the clinical practice of pediatric neurocritical care.