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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The authors measured regional cerebral 133xenon (133Xe) blood flow (rCBF), intraventricular pressure (IVP), cerebrospinal fluid (CSF) pH and lactate, systemic arterial blood pressure (SAP), and arterial blood gases during the acute phase in 23 comatose patients with severe head injuries. The IVP was kept below 45 mm Hg. The rCBF was measured repeatedly, and the response to induced hypertension and hyperventilation was tested. Most patients had reduced rCBF. No correlation was found between average CBF and clinical condition, and neither global nor regional ischemia contributed significantly to the reduced brain function. No correlation was found between CBF and IVP or CBF and cerebral perfusion pressure (CPP). The CSF lactate was elevated significantly in patients with brain-stem lesions, but not in patients with "pure" cortical lesiosn. The 133Xe clearance curves from areas of severe cortical lesions had very fast initial components called tissue peaks. The tissue peak areas correlated with areas of early veins in the angiograms, indicating a state of relative hyperemia, referred to as tissue-peak hyperemia. Tissue-peak hyperemia was found in all patients with cortical laceration or severe contusion but not in patients with brain-stem lesions without such cortical lesions. The peaks increased in number during clinical deterioration and disappeared during improvement. They could be provoked by induced hypertension and disappeared during hyperventilation. The changes in the tissue-peak areas appeared to be related to the clinical course of the cortical lesion.
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PMID:Dynamic changes in regional CBF, intraventricular pressure, CSF pH and lactate levels during the acute phase of head injury. 0 73

Complete global ischemia was produced in 39 dogs by temporary ligation of the aorta. Prior to the ischemic episode, pentobarbital (30 to 45 mg per kilogram of body weight) was administered to 19 of these dogs. The neurological effects of cerebral ischemia episodes lasting 8, 9, or 10 minutes were compared in dogs treated with pentobarbital and those not treated. At 48 hours following the ischemic episode most of the dogs made ischemic for 8 minutes were normal, whereas most animals made ischemic for 10 minutes were dead or comatose. The 9-minute ischemic period resulted in a relatively even distribution of normal and damaged dogs. There were no differences between treated and untreated dogs. Cerebral blood flow, cerebral metabolic rate for oxygen, and various cerebral metabolites were measured in dogs surviving 48 hours. Again, there were no differences between treated and undertreated dogs. We conclude that barbiturates provide no protection in this model of complete global ischemia. This conclusion supports the hypothesis that the likely mechanism of barbiturate protection in models of incomplete ischemia or hypoxia is based on cerebral metabolic depression; such a mechanism would not be expected to be effective in complete global ischemia.
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PMID:No barbiturate protection in a dog model of complete cerebral ischemia. 3 25

A woman, aged 38, lost consciousness immediately after manipulation of the cervical spine and remained in coma for nearly 5 years in a combined decorticate and decerebrate state. Cerebral angiography revealed impaired circulation in the vertebrobasilar system. The EEG initially showed generalized cerebral dysrhythmia but tended, over the years, to become more normal with desynchronized fast activity of low voltage. Neuropathological examination postmortem revealed a large cystic lesion in the pressure equalization area of the carotid and basilar circulation in the upper pons, mesencephalon, posterior hypothalamus and basal thalamus. No definite stenosis or occlusion was seen in the cerebral vessels on angiography or at the postmortem examination. The mechanism of the lesion is considered to have been temporary interference with the blood flow in the vertebrobasilar system during manipulation of the cervical spine sufficient to cause ischemia and subsequent infarction of the brainstem. The pathogenesis of vascular lesions of the brain stem following manipulation of the cervical spine is discussed briefly.
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PMID:Brainstem lesion with coma for five years following manipulation of the cervical spine. 7 77

Paget's disease of the skull is the main cause of basilar artery syndromes in the adult. They may cause various neurological symptoms, including signs of ischemia of the spinal cord or medulla, or involvement of the cranial nerves and brain stem and, also, distant symptoms due to hydrocephalus, with various mental disorders including transient, recurrent, coma. The authors discuss 30 cases found in the world literature and 6 unreported personal cases, study the clinical symptoms of these cases of basilar artery compression due to Paget's disease, and the methods of neuro-radiological investigation, and emphasize the interest, in severe forms, of early surgical decompression before the stage of severe neurological complications. Regular supervision of patients with Pagets disease is thus essential to detect at an early stage, decompensation of basilar artery insufficiency in Paget's disease. In late forms, calcitonin may be indicated.
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PMID:[Neurologic complications of pagetic basilar impressions and their surgical treatment]. 16 40

A 24-year-old woman developed bilateral blindness after recovery from coma secondary to acute intermittent porphyria. Gradual return of vision in the right eye with a permanent unilateral visual field defect and optic atrophy followed. We believe the pathophysiologic mechanism was spasm of the vessels supplying the optic disk leading to ischemia and infarction of the optic nerve.
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PMID:Optic atrophy in acute intermittent porphyria. 43 76

A high-permeability polyacrylonitrile membrane was used for hemodialysis in experimental animals with induced liver ischemia and for acute treatment of 39 patients with fulminant hepatic failure. Measurements were made of amino acids and other relevant compounds; nine patients survived. In long-term studies, the polyacrylonitrile membrane was used for hemofiltration in ten clinical cases of fulminant hepatic failure and coma. Five patients, including two pregnant women, survived.
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PMID:High-permeability membrane hemodialysis and hemofiltration in acute hepatic coma: experimental and clinical results. 53 27

The diagnosis of occlusion of the intradural vertebrobasilar artery (OIDVBA) was made by means of cerebral angiography in 22 patients. The clinical presentation, course and followup were studied in conjunction with the angiographic findings in each case and the following conclusions made. OIDVBA is not rare. It occurs one-fourth as often as occlusion of the carotid artery. The correct diagnosis is not made clinically before angiography in the majority of patients. Complete visualization of the neck and intracranial vasculature is necessary to document the occlusion. Atherosclerotic thrombosis is the most common type of occlusive lesion. The most common predisposing factors are atherosclerosis, hypertensive cardiovascular disease, diabetes mellitus, and developmental vertebrobasilar hypoplasia. Most patients with occlusion are in the 7th and 8th decades of life and transient attacks of vertebrobasilar ischemia precede the occlusion in one-half of the cases. Emboli usually lodge in the terminal portion of the basilar artery whereas thrombotic occlusions tend not to be located in a characteristic segment. A majority of patients diagnosed angiographically survive their OIDVBA, but most distal occlusions result in death, often following several weeks of coma. In the surviving majority, disturbance of gait, impairment of vision, and symptoms of transient vertebrobasilar ischemia are the most common sequelae.
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PMID:Occlusion of the intradural vertebrobasilar artery. 63 67

The pathological findings in four patients with courses characterized by acute coma and respiratory insufficiency occurring in obscure circumstances are presented. Carbon monoxide intoxication was excluded. After an early partial recovery from coma, the patients remained in a persistent vegetative state, with a tetrapyramidal syndrome. Pathologic changes consisted of infarction and demyelination of periventricular white matter, with associated necrotic foci in the basal ganglia in some cases. We propose that the prolonged hypoxia and ischemia produce a "no reflow" phenomenon causing brain edema (more pronounced in the white matter); this resulted in infarctions of white matter in the periventricular arterial end and border zones.
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PMID:Periventricular leukomalacia in adults. Clinicopathological study of four cases. 66 10

We measured cerebral oxygen extraction, cerebral blood flow(CBF), and cerebral metabolic rate (CMRO2) in comatose patients during the first 60 hours after resuscitation from cardiac arrest. Each patient was studied 2 or 3 times. CBF was determined by a modification of the Kety-Schmidt method using inhaled Xenon133. Over the study period jugular venous oxygen tension and saturation rose, while the oxygen content difference between arterial and jugular venous blood fell, indicating a progressive increase in the ratio of CBF to metabolism CBF and CMRO2 measurements confirmed this. Between 2 and 6 hours after resuscitation both measurements were severely but proportionately depressed to less than 50% of normal. After 6 hours CBF was increased disproportionately to CMRO2 so that a relative hyperemia developed and persisted for the duration of the study. Although regional inhomogeneity of flow and regional ischemia cannot be ruled out, we have found no evidence for global cerebral ischemia between 2 and 60 hours post-resuscitation as an explanation for failure of recovery. In man following cardiac arrest restoration of levels of global cerebral blood flow, which can be considered adequate relative to the depressed metabolic state of the tissue, is achieved within 2 hours of resuscitation.
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PMID:Cerebral blood flow and metabolism in man following cardiac arrest. 74 88

60 patients were included in a prospective study to evaluate the effectiveness of hyperbaric oxygenation (OHP) as a treatment of head injury coma. They were assigned to nine subgroups according to age, level of consciousness and eventual neurosurgical procedure, and then selected randomly for OHP or standard therapy. OHP was administered in one or several series of daily exposure at 2.5 ATA. However, the OHP therapy protocol was to be interrupted in 11 cases developing pulmonary, hyperoxic, or infectious complications. Overall mortality and mean duration of coma in survivors were not different in both groups, indicating that OHP was either ineffective or too intermittently applicated. Analysis of results in subgroups revealed that, in one subgroup (18 patients), the rate of recovered consciousness at 1 month was significantly higher when OHP was used. These patients were under 30 and had a brain stem contusion without supratentorial mass lesion. The view is defended that, besides its toxic action on the normal nervous tissue, OHP can counteract edema and ischemia in the zones of brain injuries.
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PMID:Hyperbaric oxygenation for severe head injuries. Preliminary results of a controlled study. 78 88


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