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Query: UMLS:C0268318 (ICP)
 10,007 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cerebral blood flow was assessed as initial slope index by 133-Xenon inhalation in 36 patients with brain tumours subjected to osmotic dehydration. The following solutions were employed: I. 20% mannitol, II. 40% sorbitol, III. 10% glycerol. Parameters affecting blood rheologic properties as Hct, plasma viscosity, red blood cell aggregation and fluidity were simultaneously studied. CBF which was reduced in the oedematous hemisphere with brain tumour increased during infusion and thereafter by mannitol or sorbitol, respectively. The blood flow response to glycerol was more delayed, less intense, but maintained longer. Hct and plasma viscosity were significantly reduced by all osmotic agents, while red blood cell fluidity fell and aggregation rose under mannitol. It is concluded that sorbitol (40%) is superior for emergency treatment with high ICP, whereas glycerol seems to be preferable to improve cerebral blood flow in oedematous brain.
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PMID:Cerebral blood flow and rheologic alterations by hyperosmolar therapy in patients with brain oedema. 212 75

The possibility of measuring cerebral blood flow by mobile bedside units with the intravenous 133-Xenon technique increased the interest to monitor haemodynamic changes after head injury and subarachnoid haemorrhage in intensive care. Time course of resting CBF after trauma is variable (reduced CBF, hyperemia) and there is no strong correlation to clinical outcome. Additional studies of CBF/CO2 reactivity show normal and impaired CO2 response in the acute stage after trauma (day 1-8). A permanently impaired CO2 reactivity correlates with severe brain damage and bad outcome (GOS 1,2). A normal or improving CO2 reactivity indicates a favourable outcome (GOS 3-5). There was no significant correlation between CBF and ICP, nor between CBF and CPP. A CPP of more than 70 mmHg did not guarantee a sufficient CBF in every case indicating the variability of the limits of autoregulation. As therapeutic hyperventilation may lead to ischemia, mannitol was preferred to reduce ICP and increased low CBF to normal values. This fact should be considered in the treatment of patients with low CBF and normal CO2 reactivity. Delayed ischemic neurological deficits ("vasospasm") are well-known as significant complications of the clinical course following SAH. Immediately postoperatively performed CBF measurements enable to detect ischemia and allow to start early antiischemic therapy. During "vasospasm" CBF showed a better correlation to the neurological status than blood flow velocity in the basal arteries measured by transcranial doppler sonography. Furthermore hyperemia after SAH could only be verified by CBF measurements.
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PMID:Xenon 133--CBF measurements in severe head injury and subarachnoid haemorrhage. 790 78

During the last few years continuous measurements of CBF by means of a thermal diffusion blood flow probe have been proposed as a possible means for monitoring the patient's CBF in a clinical setting. Also, it has been suggested that continuous CBF data from head injured patients can be correlated with other continuously recorded clinical parameters, such as ICP and blood pressure, in order to clarify pathophysiological mechanisms such as "plateau-waves". We measured regional cortical blood flow continuously with a thermal diffusion flow probe in 13 comatose head injured patients after undergoing craniotomy for evacuation of a traumatic intracranial mass lesion in order to assess the reliability and usefulness of the method. In seven patients stable Xenon-CT CBF studies were performed with the flow probe in place, in order to compare the two methods. The continuous blood flow values did not correlate with regional or global stable Xenon-CT values. These results indicate that continuous monitoring of CBF with the thermal diffusion method as currently used cannot be used in the clinical management of the patient. Further research will have to be directed to the question as to whether changes in CBF are reliably measured with this method. If this is true, the thermal diffusion flow probe with its high temporal resolution may still be useful in investigating pathophysiological mechanisms such as interaction between CBF, ICP, mean arterial blood pressure (MABP), and end-expiratory CO2 (etCO2).
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PMID:Monitoring of regional cerebral blood flow (CBF) in acute head injury by thermal diffusion. 831 Aug 62

The pathogenesis of traumatic brain swelling is unclear. Brain edema (increased water content) is considered an important cause of swelling, but there is also evidence that vasodilatation with increased cerebral blood volume (CBV) plays a role. We have evaluated early posttraumatic changes in CBV in 37 head-injured patients, using dynamic contrast-enhanced computerized tomography (CT) in combination with stable Xenon-enhanced CT for measurement of cerebral blood flow (CBF). This technique enables rapid determination of CBV without interfering with patient care. CBV values ranged from 2.0 to 10.1 ml/100 g. There was no relationship the time after injury at which the measurements were taken. CBV did not correlate with CBF in the early posttraumatic period. Patients with raised ICP (> 20 mm Hg) had significantly higher CBV that patients with normal ICP (5.4 +/- 2.1 vs 3.7 +/- 0.9 ml/100 g). Yet, the presence of signs of brain swelling on CT had no relation to the level of CBV. These data suggest that increased CBV may contribute to raised ICP, but that brain swelling is not caused by increased CBV alone, and is more likely accounted for by brain edema. We speculate that cerebral energy failure is the unifying cause of both intracellular edema and cerebral vasodilation leading to swelling of brain tissue.
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PMID:Pathogenesis of traumatic brain swelling: role of cerebral blood volume. 977 5

Intracerebral contusions can lead to regional ischemia caused by extensive release of excitotoxic aminoacids leading to increased cytotoxic brain edema and raised intracranial pressure. rCBF measurements might provide further information about the risk of ischemia within and around contusions. Therefore, the aim of the presented study was to compare the intra- and perilesional rCBF of hemorrhagic, non-hemorrhagic and mixed intracerebral contusions. In 44 patients, 60 stable Xenon-enhanced CT CBF-studies were performed (EtCO2 30 +/- 4 mmHg SD), initially 29 hours (39 studies) and subsequent 95 hours after injury (21 studies). All lesions were classified according to localization and lesion type using CT/MRI scans. The rCBF was calculated within and 1-cm adjacent to each lesion in CT-isodens brain. The rCBF within all contusions (n = 100) of 29 +/- 11 ml/100 g/min was significantly lower (p < 0.0001, Mann-Whitney U) compared to perilesional rCBF of 44 +/- 12 ml/100 g/min and intra/perilesional correlation was 0.4 (p < 0.0005). Hemorrhagic contusions showed an intra/perilesional rCBF of 31 +/- 11/44 +/- 13 ml/100 g/min (p < 0.005), non-hemorrhagic contusions 35 +/- 13/46 +/- 10 ml/100 g/min (p < 0.01). rCBF in mixed contusions (25 +/- 9/44 +/- 12 ml/100 g/min, p < 0.0001) was significantly lower compared to hemorrhagic and non-hemorrhagic contusions (p < 0.02). Intracontusional rCBF is significantly reduced to 29 +/- 11 ml/100 g/min but reduced below ischemic levels of 18 ml/100 g/min in only 16% of all contusions. Perilesional CBF in CT normal appearing brain closed to contusions is not critically reduced. Further differentiation of contusions demonstrates significantly lower rCBF in mixed contusions (defined by both hyper- and hypodense areas in the CT-scan) compared to hemorrhagic and non-hemorrhagic contusions. Mixed contusions may evolve from hemorrhagic contusions with secondary increased perilesional cytotoxic brain edema leading to reduced cerebral blood flow and altered brain metabolism. Therefore, the treatment of ICP might be individually modified by the measurement of intra- and pericontusional cerebral blood.
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PMID:rCBF in hemorrhagic, non-hemorrhagic and mixed contusions after severe head injury and its effect on perilesional cerebral blood flow. 1145 9

The objective of this study was to confirm the nature of the edema, cellular or vasogenic, in traumatic brain injury in head-injured patients using magnetic resonance imaging techniques. Diffusion-weighted imaging methods were quantified by calculating the apparent diffusion coefficients (ADC). Brain water and cerebral blood flow (CBF) were also measured using magnetic resonance and stable Xenon CT techniques. After obtaining informed consent, 45 severely injured patients rated 8 or less on Glasgow Coma Scale (32 diffuse injury, 13 focal injury) and 8 normal volunteers were entered into the study. We observed that in regions of edema, the ADC was reduced, signifying a predominantly cellular edema. The ADC values in diffuse injured patients without swelling were close to normal and averaged 0.89 +/- 0.08. This was not surprising, as ICP values for these patients were low. In contrast, in patients with significant brain swelling ADC values were reduced and averaged 0.74 +/- 0.05 (p < 0.0001), consistent with a predominantly cellular edema. We also found that the CBF in these regions was well above ischemic threshold at time of study. Taking these findings in concert, it is concluded that the predominant form of edema responsible for brain swelling and raised ICP is cellular in nature.
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PMID:Traumatic brain edema in diffuse and focal injury: cellular or vasogenic? 1667 17

Xenon assures rapid awakening and stable hemodynamics, it also has some neuroprotective effect. This is the reason why it may become an anesthetic of choice in neurosurgery. Still there is little and controversial data on its impact upon ICP. This is the first study of xenon effect upon intracranial pressure, cerebral perfusion pressure and cerebrovascular reactivity during xenon anesthesia in neurosurgical patients without intracranial hypertension. We report a slight increase in intracranial and a slight decrease in cerebral perfusion pressure during xenon anesthesia and show that cerebrovascular reactivity is preserved. Thus we conclude that xenon anesthesia is safe for neurosurgical patients without intracranial hypertension.
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PMID:[Intracranial pressure changes during xenon anesthesia in neurosurgical patients without intracranial hypertention]. 2195 14