Acta neurochirurgica. Supplement
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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
Non-invasively estimated ICP pulse amplitude strongly correlates with outcome after TBI.
An existing monitoring database of brain signal recordings in patients with head injury has been re-evaluated with regard to the accuracy of estimation of non-invasive ICP (nICP) and its components, with a particular interest in the implications for outcome after head injury. ⋯ When compared between patients who died and who survived mean nAmp showed the greatest difference, suggesting its potential to predict mortality after TBI.
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Acta Neurochir. Suppl. · Jan 2012
Near infrared spectroscopy as possible non-invasive monitor of slow vasogenic ICP waves.
We aimed to study synchronisation between ICP and near infrared spectroscopy (NIRS) variables induced by vasogenic waves of ICP during an infusion study in hydrocephalic patients and after TBI. Nineteen patients presenting with hydrocephalus underwent a diagnostic intraventricular constant-flow infusion test. The original concept of the methodology, presented in the current paper, was derived from this material. ⋯ Fluctuations of Hb and HbO(2) at baseline negatively correlated with each other, but switched to high positive values during periods of increased ICP slow-wave activity during infusion (p < 0.001). Similar behaviour was observed in TBI patients: baseline negative Hb/HbO(2) correlation changed to positive values during peaks of ICP of vasogenic nature. Correlating changes in Hb and HbO(2) may be of use as a method of non-invasive detection of vasogenic ICP waves.
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Acta Neurochir. Suppl. · Jan 2012
Bedside study of cerebral critical closing pressure in patients with severe traumatic brain injury: a transcranial Doppler study.
Cerebral critical closing pressure (CrCP) is the arterial pressure (AP) below which small arterial cerebral vessels collapse. Our objective was to estimate cerebral CrCP in 12 severe TBI patients, relating transcranial Doppler flow velocity (FV) and AP data. ⋯ The frequently found negative values do not allow us for the moment, to use any of these three methods for clinical guidance.
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Acta Neurochir. Suppl. · Jan 2012
Comparative StudyExperimental comparison of the measurement accuracy of the Licox(®) and Raumedic (®) Neurovent-PTO brain tissue oxygen monitors.
Only a few experimental reports are available on the direct comparison of Licox(®) and Raumedic(®)-Neurovent-PTO brain tissue oxygen pressure (P(br)O(2)) monitors. We compared the two systems regarding their measurement properties under experimental in vitro and in vivo conditions. ⋯ Raumedic(®) sensors measured higher P(br)O(2) values. There was no significant difference regarding overall measurement of in vitro accuracy between the two probes, which proved to be robust when used consecutively for longer periods and in different environments.