Articles: brain-injuries.
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Acta Neurochir. Suppl. · Jan 1998
Morphological and hemodynamic evaluations by means of transcranial power Doppler imaging in patients with severe head injury.
The following conditions of 17 patients with severe head injury (ages 9-76; mean 37:12 focal and 5 diffuse injuries) were evaluated during acute phase (1-14 days after injury, mean 5) by transcranial power Doppler imaging (PDI), a new color Doppler ultrasound technique: a) morphological changes via temporal window, b) hemodynamic changes in major intracranial/cervical arteries based on measured angle-corrected time-averaged mean (TAM)/ peak velocities and vessel diameter (Va), and calculated pulsatility indices (PI), vessel area (Va), and flow volume (Vf = TAM x Va). a) 1) Major trunks of intracranial vessels and circle of Willis and pathological changes in frontal/temporal lobes and midbrain were finely visualized. 2) Contusional hemorrhage and cerebral contusion demonstrated irregular hyper- and hypo-echoic lesions, respectively. 3) Delayed epidural hematoma showed a hyper-echoic band. b) 1) Decreased velocities, significant PI increase, and Va increase tendency were observed in intracranial arteries. 2) Increased velocities with Vf increase but no Va decrease indicated hyperemia rather than vasospasm. 3) Va in the intracranial vessels, however, tended to increase PDI appears useful in evaluating real-time and simultaneous morphological and hemodynamic information in pathogenesis and neurointensive care of patients with severe head injury.
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Acta Neurochir. Suppl. · Jan 1998
Continuous intracranial multimodality monitoring comparing local cerebral blood flow, cerebral perfusion pressure, and microvascular resistance.
Maintaining cerebral perfusion pressure (CPP) above 70 mmHg is currently a mainstay of neurosurgical critical care. Shalmon, et al. recently showed poor correlation between CPP and regional cerebral blood flow (CBF) [1]. To study the relationship between CPP and CBF, at a microvascular level, we retrospectively analyzed multimodality digital data from 12 neurosurgical critical care patients in whom a combined intracranial pressure (ICP)--laser Doppler flowmetry (LDF) probe (Camino, San Diego) had been placed. ⋯ Autoregulation was impaired or absent in all monitored patients. We conclude that with disrupted autoregulation, CPP above 70 mmHg does not necessarily insure adequate levels of cerebral perfusion. Restoration and maintenance of adequate cerebral perfusion should be performed under the guidance of direct CBF monitoring.
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Acta Neurochir. Suppl. · Jan 1998
Continuous monitoring of cerebrovascular pressure-reactivity in head injury.
Cerebrovascular vasomotor reactivity reflects changes in smooth muscle tone in the arterial wall in response to changes in transmural pressure or concentration of carbon dioxide in blood. We have investigated whether slow waves in ABP and ICP may be used to derive an index which reflects reactivity of vessels to changes in arterial blood pressure. ⋯ Computer analysis of slow waves in ABP and ICP is able to provide a continuous index of cerebrovascular reactivity to changes in arterial pressure, which is of prognostic significance.
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Acta Neurochir. Suppl. · Jan 1998
Effects of cerebral perfusion pressure on brain tissue PO2 in patients with severe head injury.
Ischemia causes secondary brain damage after severe head injury (SHI). Cerebral perfusion is commonly estimated by monitoring CPP, but the adequacy of cerebral oxygenation requires further measurements, such as jugular oxygen saturation or, more recently, PtiO2 monitoring. In 7 patients with severe head injury, ICP, MAP, CPP, SjO2 and PtiO2 were monitored for a mean time of 9.0 +/- 2.2 days. ⋯ Focusing on values under the thresholds of 60 mm Hg for CPP and 20 mm Hg for PtiO2, we found a relationship between CPP and PtiO2. Looking at the PtiO2 time-course, we observed a quite constant increasing trend during the first 48 hours of monitoring, then the values remained relatively constant within a normal range. Our data show that decreases of PtiO2 are not uncommon after severe head injury and therefore it seems that monitoring of PtiO2 in SHI may be useful in order to minimize secondary insults.