Acta neurochirurgica. Supplement
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Acta Neurochir. Suppl. · Jan 2002
Multicenter Study Comparative StudyMulti-centre assessment of the Spiegelberg compliance monitor: interim results.
Analyses of a multi-centre database of 71 patients at risk of raised ICP showed that in head injured patients (n = 19) and tumour patients (n = 13) clear inverse relationships of ICP vs compliance exist. SAH patients (n = 5) appear to exhibit a biphasic relationship between ICP and compliance, however greater numbers of patients need to be recruited to this group. Patients with hydrocephalus (n = 34) show an initial decrease in compliance while ICP is less than 20 mmHg, thereafter compliance does not show a dependence upon ICP. ⋯ Preliminary time-series analyses of the ICP and compliance data is revealing evidence that the cumulative time compliance is in a low compliance state (< 0.5 ml/mmHg), as a proportion of total monitoring time, increases more rapidly than the cumulative time ICP is greater than 25 mmHg. Before trials testing compliance thresholds can be designed, we need to consider not just the absolute threshold, but the duration of time spent below threshold. A survey may be required to identify a consensus of what is the minimum duration of raised ICP above 25 mmHg needed to instigate treatment.
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Acta Neurochir. Suppl. · Jan 2002
Review Case ReportsDeep brain stimulation of the globus pallidus internus (GPI) for torsion dystonia--a report of two cases.
Generalized dystonia is known as a type of movement disorder in which pharmacotherapeutic options are very limited. Deep Brain Stimulation (DBS) is well established for Parkinson's disease (PD) and tremor dominant movement disorders. We report on two cases of generalized dystonia which were successfully treated by chronic high frequency stimulation in the Globus pallidus internus (GPI). ⋯ The medication was continuously reduced. At the 24 month follow-up the effect of stimulation remained unchanged. However high stimulation parameters are required to maintain an optimal effect (mean 3.5 V, 400 microseconds, 145 Hz).
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Induced blood pressure elevation has become a popular treatment for intracranial hypertension. However, there remains a concern that in some patients blood pressure elevation will further elevate ICP. This study was conducted to test the hypothesis that increasing MAP decreases ICP. ⋯ In patients with lower GCS and high SjvO2 an increase in MAP resulted in an increase in ICP. We concluded that in the majority of studies increasing MAP was followed by an increase in ICP. CPP therapy has a selective indication in patients with high GCS, low SjvO2 and increased ICP.
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Acta Neurochir. Suppl. · Jan 2002
Continuous cerebral compliance monitoring in severe head injury: its relationship with intracranial pressure and cerebral perfusion pressure.
Cerebral Compliance describes the ability of cranial content to accommodate volume variations. Intracranial vascular compartment is thought to be one of the most important determinants of Compliance. Cerebral perfusion pressure (CPP) has a significant influence upon the calibre of cerebral vessels and consequently, upon blood volume. ⋯ At CPP > or = 60 mmHg Compliance decreased with CPP (R2 = 0.83). In the range of low CPP vasoparalysis is impending. However, when ICP is pathological, at high CPP our results may express vasodilatation instead of expected vasoconstriction from normal autoregulation.
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Acta Neurochir. Suppl. · Jan 2002
Approximate entropy: a regularity statistic for assessment of intracranial pressure.
Waveform analysis of ICP and mABP provideqs important information about cerebrovascular reactivity and intracranial compliance. Traditionally spectral analysis and correlation statistics have been used despite certain limitations. Approximate entropy (ApEn) is an established measure of system regularity; which can change with pathology. This study defines a novel method for application of ApEn to the ICP/mABP waveform, and reports changing ApEn with pathophysiology in the rodent brain. ⋯ This study defines a system for analyzing the transfer of random fluctuations in mABP waveform to the ICP waveform. ApEn appears to be responsive to changes in intracranial compliance and/or cerebrovascular resistance, therefore more formal studies of the sensitivity and specificity of this novel measure are warranted. These initial findings suggest that ApEn may be a useful adjunct measure of the ICP waveform.