Acta neurochirurgica. Supplement
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Acta Neurochir. Suppl. · Jan 2005
ReviewNear infrared spectroscopy in brain injury: today's perspective.
The technique of near infrared spectroscopy (NIRS) is based on the principle of light attenuation by the chromophores oxyhaemoglobin (HbO2), deoxyhaemoglobin (Hb) and cytochrome oxidase. Changes in the detected light levels can therefore represent changes in concentrations of these chromophores. Clinical use of NIRS in the brain has been well established in neonates where transillumination is possible. ⋯ Recent technical advances have led to the development of compact, portable instruments that detect changes in optical attenuation of several wavelengths of light. Near infrared spectroscopy is an evolving technology that holds significant potential for technical advancement. In particular, NIRS shows future promise as a clinical tool for bedside cerebral blood flow measurements and as a cerebral imaging modality for mapping structure and function.
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Acta Neurochir. Suppl. · Jan 2005
ReviewPhenomenological aspects of consciousness--its disturbance in acute and chronic stages.
The meaning of a disturbance of consciousness is completely different in an acute as opposed to a chronic stage. In the acute stage, the grade of arousal is the most essential component in order to assess the changes of the level of intracranial pressure in neurosurgical emergency room. ⋯ We propose the difference in conception between consciousness and mind; that is, consciousness consists of psycho-sensory afferent system, mind of psycho-motor efferent and afferent system, and memory and language as liaison officers between them. This proposal would play a role to understand mental change in the natural aging processes, when memory and cognition are deteriorating gradually, but is still in evolution in the field of culture.
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Acta Neurochir. Suppl. · Jan 2005
Clinical TrialMRI study of cerebral blood flow and CSF flow dynamics in an upright posture: the effect of posture on the intracranial compliance and pressure.
Postural related changes in cerebral hemodynamics and hydrodynamics were studied using Magnetic Resonance Imaging (MRI) measurements of cerebral blood flow and cerebrospinal fluid (CSF) flow dynamics. Ten healthy volunteers (mean age 29 +/- 7) were studied in supine and upright (sitting) postures. A Cine phase-contrast MRI technique was used to image the pulsatile blood flow to the brain, the venous outflow through the internal jugular, epidural, and vertebral veins, and the bi-directional CSF flow between the cranium and the spinal canal. ⋯ A considerable smaller amount of CSF flow between the cranium and the spinal canal (58%), a much larger intracranial compliance (a 2.8-fold increase), and a corresponding decrease in the MRI-derived ICP were also measured in the sitting position. These changes suggest that the increased cerebrovascular and intracranial compliances in the upright posture are primarily due to reduced amounts of blood and CSF residing in their respective intracranial compartments in the upright position. This work demonstrates the ability to quantify neurophysiologic parameters associated with regulation of cerebral hemodynamics and hydrodynamics from dynamic MR imaging of blood and CSF flows.
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Acta Neurochir. Suppl. · Jan 2005
Controlled Clinical TrialThe importance of major extracranial injuries by the decompressive craniectomy in severe head injuries.
Neurosurgical therapy aims to minimise the secondary brain damage after a severe head injury. This includes the evacuation of an intracranial space occupying bleeding, the reduction of intracranial volumes, in hematocephalus an external ventricular drainage, and the conservative therapy in order to influence an increased intracranial pressure (ICP) and a decreased p(ti)02. ⋯ The prognosis after decompression depends on the clinical signs and symptoms on admission, the patients age and the existence of major extracranial injuries. Our guidelines for an indication for decompressive craniectomy after failure of conservative interventions and evacuation of space occupying hematomas include a patients age below 50 years without multiple trauma, a patients age below 30 years in the presence of major extracranial injuries, a severe brain swelling on CT scan, the exclusion of a primary brainstem lesion or injury and the intervention before irreversible brainstem damage and secondarily while monitoring ICP and p(ti)02 in an interval up to 48 hours after the accident before irreversible brainstem damage or generalised brain damage has occurred.
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Acta Neurochir. Suppl. · Jan 2005
Clinical TrialCerebral blood flow (CBF)-directed management of ventilated head-injured patients.
Ischaemic brain damage has been shown to be an important contributing factor causing head injury fatality. Maintenance of an adequate cerebral perfusion pressure is difficult in patients with elevated intracranial pressure (ICP) and deranged cerebral vasoreactivity. Thirty-five cases of ventilated moderate-to-severe head-injured patients were prospectively studied, correlating their cerebral haemodynamic abnormalities, neurochemical disturbances (using microdialysis methodology) and clinical outcome. ⋯ The need for haemodynamic intervention in this group of ventilated patients with moderate-to-severe head inury can be made logical when these abnormalities are identified daily. The success of management was reflected by a stable or improved ICP, CPP, intracerebral metabolic deranagement and survival.