Acta neurochirurgica. Supplement
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Acta Neurochir. Suppl. · Jan 2000
Low extracellular (ECF) glucose affects the neurochemical profile in severe head-injured patients.
Glucose (Gluc) is the main energy source for the brain. After severe head-injury energy demand is massively increased and supply is often decreased. In pilot microdialysis studies, many patients with severe head-injury had undetectable glucose concentrations, probably reflecting changes in metabolism and/or reduced supply. ⋯ There was also no correlation between outcome and the dialysate glucose. The results indicate that low ECF glucose is almost always present in severe head-injury. Moreover, the lack of correlation between low glucose and outcome, however, suggests that other energy substrates, such as lactate, are important after TBI.
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Acta Neurochir. Suppl. · Jan 2000
Comparative StudyClinical experiences with the dual-switch valve in patients with normal pressure hydrocephalus.
In patients with normal pressure hydrocephalus (NPH) we compared the postoperative results reference to the implanted valve type. In 117 patients diagnosed with normal pressure hydrocephalus there was placement of 47 Cordis Standard valves (CSV), 20 Cordis Orbis Sigma valves type I (OSV) and 50 Miethke Dual-switch valves (DSV). Ninety-five patients (36/19/40) were re-evaluated. ⋯ The course of disease in patients with NPH is influenced by the stage of disease--degree of cerebral atrophy--and also by the implanted valve type. The great amount of overdrainage complications and subdural hematomas in the Cordis Orbis Sigma valve group may be an argument against this valve. Our clinical experiences with the Miethke Dual-switch valve show that this hydrostatic valve may be advantageous for patients with NPH.
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Acta Neurochir. Suppl. · Jan 2000
Non-invasive cerebral perfusion pressure (nCPP): evaluation of the monitoring methodology in head injured patients.
The method of direct calculation of cerebral perfusion pressure (CPP) as the difference between mean arterial pressure and intracranial pressure (ICP) produces a number, which not always adequately expresses brain perfusion. We investigated an alternative non-invasive method, based on waveform analysis of Transcranial Doppler blood flow velocity in Middle Cerebral Arteries (MCA). 25 consecutive head injured patients, paralysed, sedated and ventilated were studied. Intracranial pressure (ICP) arterial blood pressure (ABP) were monitored continuously. ⋯ An absolute difference between real CPP and CPPe was less than 10 mm Hg in 82% of measurements and less than 13 mm Hg in 90% of measurements. The method demonstrated a high potential to detect both short-term and long-term changes in CPP. The method is of potential benefit for the intermittent measurement and continuous monitoring of changes in brain perfusion pressure in situations where the direct measurement of CPP is not available or its reliability is in question.
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Acta Neurochir. Suppl. · Jan 2000
Distinguishing between cellular and vasogenic edema in head injured patients with focal lesions using magnetic resonance imaging.
Having determined that edema and not vascular engorgement is the major factor leading to traumatic brain swelling, the objective of this study was to determine which type of edema, cellular or vasogenic, is responsible for increased tissue water in patients with focal lesions. Severely head injured patients (GCS 8 or less) were transported to imaging suites for measurement of brain water and apparent diffusion coefficient (ADC) using magnetic resonance technique. Cerebral blood flow by stable Xenon method was also measured in the regions of interest. ⋯ The increase in water was associated with reduced ADC signifying a predominant cellular edema. The ADC in the contralateral hemisphere was near normal value. Cerebral blood flow values in the regions of interest were above ischemic levels suggesting that factors other than ischemia are responsible for the cytotoxic swelling in patients with focal injury.